W1128: Reducing Barriers to Adoption of Microirrigation

(Multistate Research Project)

Status: Inactive/Terminating

Project Menu

SAES-422 Reports

Annual/Termination Reports:

[12/13/2004] [11/05/2005] [01/03/2007] [12/20/2007] [11/01/2008]

Date of Annual Report: 12/13/2004

Report Information

Annual Meeting Dates: 11/17/2004 - 11/19/2004
Period the Report Covers: 10/01/2004 - 12/01/2004

Participants

Alam, Mahbub (malam@ksu.edu) - Kansas State University; Berrada, Abdel (Abdel.Berrada@Colostate.edu) Colorado State University; Branch, Bill (bbranch@agctr.lsu.edu) Louisanna State University; Clark, Gary (gac@ksu.edu) - Kansas State University; Colaizzi, Paul (pcolaizzi@cprl.ars.usda.gov) USDA/ARS, Bushland, TX; Fares, Ali (AFares@Hawaii.edu) University of Hawaii, Manoa; Lamm, Freddie (flamm@oznet.ksu.edu) - Kansas State University; Lakso, Alan (anl2@nysaes.cornell.edu) - New York State Exp. Sta.; Lesikar, Bruce (b-lesikar@tamu.edu) Texas A&M University; ONeill, Mick (moneill@nmsu.edu) New Mexico State University; Neibling, Howard (hneiblin@uidaho.edu) University of Idaho; Parsons, Larry (lrp@lal.ufl.edu) University of Florida; Prestwich, Clarence (cprestwich@nwcc.nrcs.usda.gov) USDA/NRCS, Portland, OR; Robinson, Peter (peter.robinson@por.usda.gov) USDA/NRCS, WNTSC, Portland, OR; Roman-Paoli, Elvin (eroman@uprm.edu) University of Puerto Rico; Schwankl, Larry (schwankl@uckac.edu) - University of California; Shackel, Ken (kashackel@ucdavis.edu) - University of California; Shock, Clint (Clinton.Shock@oregonstate.edu) Oregon State University; Singh, Prem (psingh@uog9.uog.edu) University of Guam; Stanley, Craig (cds@ifas.ufl.edu) University of Florida; Taber, Henry (taber@iastate.edu) Iowa State University; Yitayew, Muluneh (myitayew@email.arizona.edu) University of Arizona

Brief Summary of Minutes

Meeting Minutes
W-1128 Annual Meeting
November 17-19, 2004
Tampa, Florida

The meeting was opened at 8:10 am by Clint Shock. Members (M) and guests (G) present included: Gary Clark (M, Secretary), Muluneh Yitayew (M), Larry Schwankl (M), Clint Shock (M, Chair), LeRoy Daugherty (Admin. Advisor), Craig Stanley (M, Vice Chair), Mick ONeill (M), Howard Neibling (M), Clair Prestwich (G), Freddie Lamm (M), Paul Colaizzi (M), Ali Fares (G), Bruce Lesiker (M), Alan Lasko (M), Rick Piccioni (G) Ken Shackel (M), Henry Taber (M), Bill Branch (M), Abdel Berrada (M), Peter Robinson (G), Mahbub Alam (M), Elvin Roman-Paoli (M), Dan Rogers (G), Andre Peirera (G), Prem Singh (M) [M=member; G=Guest]

Members introduced themselves. Minutes from the 2004 meeting were discussed and approved.

LeRoy Daugherty addressed the group and discussed the format for the annual report. This report will be the final report for the W-128 project. We just started the W-1128 project on Oct 1, 2004. The report needs to follow the App D SAES-422 format for multistate research activity. The impact (or potential impacts) section is very important. Each participant needs to work their own AES director to get their projects into the CRIS system. A copy of the memo from the USDA to each of the AES directors was passed out. A printed copy of the project proposal was handed out. The App E information (listing of members) is in that printed copy. The members list is a dynamic list and can change with time in the project. A screen print of the NIMSS website was handed out. Project participants can access as Guests. Information on this project and members can be located on that site. Other projects and project members can be viewed as well.

Clint Shock discussed the annual report. Gary Clark suggested that the Secretary handle the annual report. The proposed duties are: Secretary - Meeting minutes and annual report; Vice-Chair - arrangements for the annual meeting; Chair - Conduct the annual meeting

Larry Schwankl suggested that we discuss the duties of the officers during the business meeting. We also need to discuss the 2005 meeting location and elect a new secretary.

State Progress Reports were conducted on Wednesday and Friday. Details are provided at the end of these minutes.

Business Meeting:

1. Location and date for 2005 meeting.
The 2005 IA meeting is Nov 6-8 in Phoenix; the 2005 ASA meeting is Nov 6-10 inSalt Lake City.
The group planned to have the meeting in Phoenix November 2-4, 2005 (Muluneh Yitayew, local host). A motion made by Larry Parson, seconded by Larry Schwankl. Motion passed.

2. Motion to change the duties of the secretary to take the meeting minutes and to compile the annual report. Motion made by Freddie Lamm, seconded by Craig Stanley. Motion passed. Gary will email a shell format of the annual report to all members. Report needs to be completed by 60 days after the annual meeting. Gary would like the individual annual reports emailed to him by December 1 in the correct format.

3. Hank, Ken and Freddie will serve as a nominating committee for the proposed new secretary. Motion was made and passed.

4. Discussion on project participation. Many listed members do not come to the annual meetings, but are listed as project members. Active members pull the annual report together and develop the project proposals. However, many inactive members do not contribute, but are still listed as members. LeRoy D. explained how the regional project process works. Project participants can be added to the project by the individual state AES directors; their participation is not determined by the current/active project members. Following discussion focused on inactive members. Freddie made a motion that LeRoy bring a concern to the other AES directors that there are some concerns from this committee about inactive membership. Seconded by Ken S. Discussion followed with many viewpoints. While concerns exist, the impacts to the group are minimal. Motion wasa withdrawn. Presentations at the next meeting might be arranged around objectives, milestones and impacts.

5. Milestones for 2005. Group discussed milestones for 2005. Project participants were identified with each milestone and a milestone group leader. Larry & Craig suggested that the committee chair coordinate with each of the milestone subtopic groups. Each group needs to coordinate among themselves about what they will do over the next year. The meeting in 2005 should focus around project objectives and milestones.

Thursday Tour (11/18/2004)
1. Small container ornamentals (Rick Brown). All drip irrigated using elevated collapsible emitting hose (drip tape)
2. Drip irrigated trees (oaks, citrus,&). County agent is doing a study of scheduling using tensiometers.
3. Microspray irrigated bamboo site visit.
4. New Gulf Coast Research and Education Center facilities
5. Dover Research Center Strawberry research
6. Strawberry farm visit (Carl Grooms)

Friday, 11/19/2004. Election of new secretary. Two nominations from the nominating committee. Ali Fares and Mick ONeill. No other nominations were provided. Mick ONeill was elected as the incoming secretary for 2005.

The meeting was adjourned on Friday November 19, 2004 at 11:30 am.

These minutes are respectfully submitted by:
Gary Clark, Secretary, W1128
Kansas State University - Department of Biological and Agricultural Engineering
gac@ksu.edu 785-532-2909

Summary of State Reports (11/17/2004):

1. Prem Singh Univ. of Guam. Discussed a lysimeter facility and irrigation scheduling study for watermelon. The site was instrumented to measure soil water potential and leachate. Temperatures under the black plastic mulch reached 76 C during the day. These high temps killed the transplants. A soil salinity study was also discussed. Soil salinity was measured at different positions with respect to the drip lateral.
2. Elvin Roman-Paoli Univ of Puerto Rico. Presented studies that address objective 3. Eval. Of soil moisture level on growth and productivity of young citrus and avocado. Trees were irrigated with microsprinklers and scheduled with tensiometers (10-15 cb, 30-35 cb, rainfed).
3. Ali Fares Univ. of Hawaii-Manoa. Irrigation scheduling for optimum plant water and nutrient uptake. Presented information on the crops and production systems in Hawaii. Work focuses on irrig. scheduling for tomato with drip irrigation. Presented information on use of ECH20 probes and EasyAg probes.
4. Paul Colaizzi USDA/ARS, Bushland, TX. Subsurface drip irrigation research in Texas. Subsurface drip irrigation (SDI) may be up to 5% in the panhandle of TX. Advantages of SDI in TX: Better crop response under deficit irrig. compared to LEPA and spray irrig.; increased WUE under deficit irrig.; good response with grain sorghum and cotton. SDI has resulted in improved earliness of maturity in cotton. Results were presented for cotton grown under dryland, MESA (mid elevation spray application), LESA (low elevation spray application), LEPA (low energy precision application), and SDI. Irrigation treatments were set at levels of 0.25, 0.50, 0.75, and 1.00 fractions of non-stressed crop ET (or full ET). SDI performed better than other treatments at levels of 0.25 and 0.50.
5. Henry Taber Iowa State University, Ames, IA. Presented results on objectives 1 and 4. Drip irrigated bell peppers were scheduled using (1) tensiometers or Watermark sensors set at 25 - 30 kPa (25% depletion) and (2) crop water balance (ET-based). One pepper variety had a significantly greater yield (12% or 235 bu/ac) with treatment 2 as compared to treatment 1.
6. Mick ONeill New Mexico State University, Farmington. Water supply is reservoir storage from the Navajo Dam. Levels were near full in 1999, 2000, 2001. Levels started to decline in 2002 and are currently very low. Subsurface drip irrigation for field crops. Purpose to evaluate SDI for field crops and to train NAPI technicians. Depth of drip tape influenced yield of corn. Also discussed subsurface drip for hybrid poplar. A nearby timber mill will use all of the hybrid poplar that can be produced.
7. Larry Parsons University of Florida, Lake Alfred, FL. Presented information on water use of citrus. Water allocations are being reduced. Value of juice oranges is based on Brix (pounds solids) and juice content. Some studies have indicated that mild stress in the fall may increase the Brix value without reducing yield. Studies were designed to address this issue using Valencia orange on a Swingle citrumelo rootstock.
8. Larry Schwankl University of California. Measurement of chemical precipitation in microirrigation systems primarily iron. Can treat by precipitating in a pond or reservoir, or treating with phosphonic acid. Two sites are under study (2ppm iron and 18 ppm iron). Chemicals that are being studied: LineMaster, Microclean, Lineout, Sureflow, and Driprite 3000.
9. Ken Shackel Univ. of California Davis. Regulated deficit irrigation (RDI) during hull split in almonds. Benefits may include speed up hull split, reduce hull rot, reduce water use. Studies investigated timing and amount of midday stem water potential stress
10. Muluneh Yitayew University of Arizona. Water and salinity management for corn in an arid environment. Evaluated seasonal irrigation requirements for field corn under drip and furrow irrigation. Developed a yield function for field corn and a crop coefficient curve based on heat units. A second presentation was provided on a salinity study. Water with different salinity levels was applied using SDI to corn plots.

State Reports Continued (11/19/2004)

11. Alan Lasko Cornell University. Measurement and modeling of water use by apple trees in NY. Measured water use rates for orchards using sap flow gauges. Found high variability among measured results from gauges placed on similar trees. Also used whole plant gas exchange to calibrate sap flow gauges this improved results. Also measured climatic data in the orchard to assess boundary layer flow conditions.
12. Howard Neibling University of Idaho. Drip irrigation and irrigation scheduling in Idaho. Studied use of drip irrigation for winter wheat production. Used Watermark sensors to measure soil water potential in the drip irrigated wheat plots. Also conducting studies on microsprinkler irrigation of sugar beets.
13. Gary Clark - Kansas State University, Manhattan. Hydraulic performance of drip irrigation tubing products with livestock lagoon wastewater. Hydraulic performance data for the past 2 years was presented. A lysimeter study on drip irrigation of Poplar trees with livestock lagoon wastewater was initiated in 2004.
14. Freddie Lamm - Kansas State University, Colby. Studies on simulated LEPA and SDI for corn in NW Kansas. Drip lines were positioned about 15-in. deep in alternate beds between plant rows. Presented 7 years of results. A SDI frequency of irrigation study was also presented.
15. Clint Shock Oregon. Microirrigation of hybrid poplar. Did studies on: a comparison of microirrigation systems on poplar; poplar clone evaluations; bulking of potato clones under drip; drip tape and potato seed configuration; options for automation and frequency of drip on onions; timing of stress on drip irrigated onions; evaluation of Vydate through drip for control of thrips; demonstration of corn and alfalfa forage production, N-rate for drip irr. Onion and carrot seed production. Presented results from drip irrigated hybrid poplar plots.

Accomplishments

Objective 1. To evaluate and refine microirrigation management strategies to promote natural resource protection and optimal crop production. A research SDI system at Colby, KS has performed well for 16 seasons with very little degradation in hydraulic performance. Three years of research on the effect of SDI frequency under deficit irrigation for corn, indicate that frequency does not affect corn yields on the deep silt loam soils of the Central Great Plains in the semi-arid climate. A four-year almond RDI (regulated deficit irrigation) study in CA was completed, and demonstrated the benefits of reducing irrigation during the hull split period to control hull rot disease and improve nut harvestability with no detrimental effects on overall productivity. Water savings using RDI were strongly dependent on soil conditions, with a documented water savings, compared to full irrigation requirements, of 65% under deep soil conditions. Under shallow soil conditions there were no water savings. Hydrus2D, model simulations were conducted in CA for 4 different pressurized irrigation systems; each associated with a typical crop. The study allowed for specification of root water and nitrate uptake, affecting the spatial distribution of water and nitrate availability between irrigation cycles. For each soil type and emitter type, the spatial patterns of water content and nitrate concentration were determined for various fertigation strategies, and leaching potentials were evaluated. The fate of pollutants from subsurface drip irrigation of septic tank effluent is being studied in soil-filled containers at the UC Davis Wastewater Treatment Plant. Data from the container tests are used to refine a model (Hydrus 2D) that predicts the adsorption and biodegradation of pollutants in the soil. The primary constituents of concern are nitrogen compounds. A volume balance ellipsoid based drip irrigation scheduling model was developed in AZ. It is currently being tested against drip irrigated chile and onions. The model allows the user to specify the shape of the ellipsoids based on the soil type and to specify the water holding capacity of the ellipsoid next to the emitter and then for the other four ellipsoids that make up the other depths. IA evaluated weather (ET) and soil (tensiometers) based irrigation scheduling methods for bell peppers grown with black plastic mulch and microirrigation, and showed equal performance for yield and fruit quality (IA). Both scheduling systems provided 80% of ETr. There were significant (P<0.05) variety responses to scheduling method with the Aristotle variety producing a 12% yield increase with the ET based scheduling system. In a FL citrus irrigation management study, irrigation was stopped on microirrigated Valencia oranges for 5 months in winter and early spring, 2004. Brix increased significantly which is economically beneficial. Irrigation was reduced by at least 10% by not irrigating in the winter. Research in NY showed that basal crop coefficients for apples related to grass reference ETo developed in arid climates are not valid for apples in humid climates due to differences in boundary layers of grasses and orchards. The coupling of the trees to bulk air makes air VPD and stomatal behavior more important than in grass. A modified apple-specific Penman-Monteith equation was developed that adjusts for the differences. This apple-specific model was better correlated to the measured tree water use than ETo. A simple irrigation schedule for strawberries is being evaluated on a LA research station. Soil moisture, water flow rate and weather variables are being analyzed to validate model. Several soil water probes (Echoprobe, EasyAg) are being evaluated in FL to see how well they measure soil water content under microirrigated citrus in Florida sandy soils. Both probes need soil specific calibration, but perform acceptably in sandy soils. Watermark soil moisture sensors and a Hansen data logger were demonstrated in Idaho as a tool for improved irrigation scheduling for sugarbeet production. Five grower fields were monitored and three were scheduled in 2004 using soil moisture sensor readings. Irrigation scheduled using soil sensors had fewer irrigation events. Harvest observations in two of the fields showed equal or greater yield with 2-4 less irrigations (3-6 less water). Four tape depths were evaluated in an SDI trial in NM with different field crops. Germination through SDI was not adequate for alfalfa at any tape depth. A small, two-row planter for potatoes was used to successfully obtain uniform plant stands in all tape depth treatments. Corn stands were directly related to tape depth ranging from a high of 98% in the 15 cm treatment to a low of 64% in the 30-cm treatment. Corn yield, was significantly different between tape depth treatments due significant stand differences. There were no significant differences between treatments for potato yield. Also in NM, ten hybrid poplar clones were evaluated for adaptation potential in the Four Corners region. Total ET amounted to 660 mm while total application was 686 mm for the 2 year old trees. A Minolta SPAD-502 chlorophyll meter was used to measure chlorosis. Clone OP-367 had the highest SPAD reading throughout the season. OP 367 was the tallest clone after two seasons reaching a mean height of 4.1 m and had the largest basal diameter of 9.1 cm. Objective 2. To improve, modify, and evaluate microirrigation system design and components for natural resource protection and optimal crop production. Lab tests in KS measured the effect of NH4-N concentrations in livestock lagoon water on required chlorine dosing to maintain a free residual chlorine level of 1-2 ppm. Lagoon water treated with acid reduced chlorine demand. Lab tests conducted to investigate the growth of biological organisms from livestock lagoon wastewater in a std drip tube and two others designed for use with wastewater showed no difference among tube types. A KS field study to evaluate clogging with four different heavy-wall microirrigation tubing products and livestock lagoon wastewater has shown that standard tubes have performed as well as tubes designed for use with wastewater. A new microsprinkler design (CA) has been developed, tested and patented. The design allows individual addressing, opening and closing of each microsprinkler emitter in a linear test array consisting of 50 sequential microsprinklers. Individual emitter activity is controlled remotely by a radio frequency controller powered by a solar panel. The design promises low cost, high precision delivery of water and dissolved solutes (fertilizers). Three years of field study to evaluate one, two, three, and four driplines per row of watermelon crop found no significant difference in watermelon yield, percent Brix (sugar content), crop cover, and leachate, in the very shallow (15 to 25 cm deep) Guam Cobbly Clay soil. However, automated irrigation scheduling, using switching tensiometers set at 25 cb, applied significantly more irrigation water under three and four driplines; there was no leachate under any of the treatments. Frequency irrigation was inversely related to the number of drip lines. Distribution uniformity (DU) was measured on 39 drip-irrigated strawberry fields in coastal California. The overall average DU was 80%. Factors that cause low uniformity included undersized lateral connections (spaghetti tube), too long of lateral length, unevenly set manifold valves, low pressure in the laterals, and too much elevation variation within blocks and fields. A database was developed of 312 microirrigation evaluations in CA carried out over the last 5 years. System (pump) pressures ranged widely; 60% of the systems operated at higher pressures than required, 30% operated at 10 psi higher than required, and the average potential pressure savings on 20% of the fields was 29 psi. Identified losses in the distribution system as a primary source of excess pressure loss, including extensive use of pressure regulation valves. Objective 3. To assess and develop decision criteria for adoption of microirrigation technologies. Seven years of field research in KS comparing SDI to simulated LEPA sprinkler irrigation indicated that LEPA performed better in 4 extreme drought years primarily due to higher kernels/ear and that SDI performed better in 3 normal to wet years primarily due to higher kernel weight. In TX, yield, water use efficiency, and various other parameters using SDI were greater than LEPA or spray irrigation for both cotton and grain sorghum for irrigation levels at 25% and 50% of full irrigation (i.e., full crop evapotranspiration); however, yield, water use efficiency, and various other parameters using LEPA and spray irrigation were either numerically or statistically greater than for SDI at 75% and 100% of full irrigation. A second season of cotton is nearly complete. SDI has also been compared with furrow irrigation of cotton for 3 years on a Louisiana research station using soil moisture meters to initiate irrigation. An increased yield from SDI was found in one dry year but not in two years with normal rainfall. Micro-spray irrigation has been compared with furrow irrigation of sweet potatoes for two years on a Louisiana research station using an ET-based scheduler. No significant differences in yields were found. Objective 4. To promote appropriate microirrigation technologies through formal and informal educational activities. Several workshops, seminars, field days, and poster sessions were presented on various aspects of microirrigation. These included: Water quality issues for SDI were presented at SW Kansas Ag Agent updates in Fall 2004; An SDI technology field day held at Colby, Kansas on Aug. 10, 2004 attracted 139 participants; 58 miscellaneous oral presentations, poster presentations, tours and discussions related to SDI by Freddie Lamm; Benefits of RDI were given to the annual meeting of the California Almond Board, and the California Dried Plum (prune) Advisory board; Sessions were presented to 197 growers at an Iowa winter conference, Jan. 30, and summer field day, July 12; A report on a new microsprinkler design and poster were presented at the Fertilizer Research and Education Program Conference, Tulare, CA September 2004; Explanation and demonstration of irrigation scheduling techniques for SDI, micro-spray and drip tape under plastic mulch has been provided for farmers attending annual Louisiana research station field days; Presentations given to several grape and apple grower and wine conferences in NY emphasized appropriate uses and amounts of irrigation for humid climates (this information has been incorporated into a new viticulture curriculum at Cornell University); More than 25 University of Guam students and 15 elementary school students visited the microirrigation field experiments at Yigo Agricultural Experiment Station; 6 workshops were presented (4 in English and 2 in Spanish) to CA strawberry farmers and irrigators, consultants, and irrigation dealers on ways to improve microirrigation system distribution uniformity; A technical presentation on Subsurface Drip and Spray Distribution Systems was presented at the VA Department of Health Advanced Onsite Training Conference, March 2004. A presentation on "Irrigation Technology. " was given at a regional meeting of the TX Agricultural Industries Association, Nov. 2004. Plans for 2005: Project members will focus on the milestones established in the new project (W-1128). Each of the 2005 milestones has one or more responsible members with an activity leader. Leaders will coordinate with others to obtain and compile information related to the milestones. Work will focus on an SDI survey, a report on guidelines for drip irrigation with wastewater, SDI installation and evaluation guidelines, and guidelines for ETbased scheduling procedures.

Publications

Alam, M., and R. Zimmerman. 2003. Plastic mulch and drip irrigation effects on Kabocha squash yield and soluble solids content. In Water-Saving Agriculture and Sustainable Use of Water and Land Resources. Proceedings of International Conference held on Oct. 26-29, 2003, in Yangling. Shaanxi. P. R. China. Edited by S. Kang, B. Davies, L. Shan, and H. Cai. Vol. 1, pp. 370-375. Published by Shaanxi Science and Technology Press. Ajwa, H.A., T.J. Trout. 2004. Drip application of alternative fumigants to MeBr for Strawberry Production in California. HortScience. 39(7):1707-1715. Aziz Z. Abidine, Brian C. Heidman, Shrini K. Upadhyaya, and David J. Hills. 2004. Autoguidance system operated at high speed causes almost no tomato damage. California Agriculture. 58 1(1): pp 44-47. Beggs, R.A., G. Tchobanoglous, D. J. Hills, and R. W. Crites. 2004. Modeling Subsurface Drip Application of Onsite Wastewater Treatment System Effluent. In: On-Site Wastewater Treatment, ed: K. R. Mankin. pp 92-103. St. Joseph, MI.: ASAE. Bronson, Kevin, Randy Boman, Jim Bordovsky, and Dana Porter. 2004. Nutrient Management of Subsurface Drip Irrigated Cotton. Texas Agricultural Experiment Station. Texas A&M University Agricultural Research and Extension Center - Lubbock. http://lubbock.tamu.edu/soilfertility/pdfs/dripirrigatecot.pdf Clark, G. A., F. R. Lamm, and D. H. Rogers. 2004. Water temperature effects on the discharge rate of collapsible emitting hose. Presented at the Irrigation Association International Irrigation Technical Conference, November 14-16, 2004, Tampa, FL. Available from Irrigation Assn., Falls Church VA. Colaizzi, P. D., Schneider, A. D., Evett, S. R., and Howell, T. A. 2004. Comparison of SDI, LEPA, and spray irrigation performance for grain sorghum. Trans. ASAE 47(5):1477-1492. Colaizzi, P.D., S. R. Evett, and T. A. Howell. 2004. Comparison of SDI, LEPA, and spray irrigation performance for cotton in the North Texas High Plains. CD-ROM. Irrigation Association Annual Meeting, 14-16 Nov, Tampa, FL. Colaizzi, P.D., S. R. Evett, and T. A. Howell. 2004. Irrigation capacities and methods for cotton in the Northern High Plains. In Proc. 2004 High Plains Groundwater Resources Conference, Soil and Water Conservation Society of America, 7-9 Dec, Lubbock, TX. Dragoni, D., A.N. Lakso, and R.M. Piccioni. 2004. Transpiration of an apple orchard in a cool humid climate: measurement and modeling. Acta Hort. (in press). Enciso, Juan, Dana Porter, Jim Bordovsky, and Guy Fipps. Revised 2004. Maintaining Subsurface Drip Irrigation Systems. Fact sheets L-5406 (English) and L-5406S (Spanish). Texas Cooperative Extension, College Station, TX. Gardenas, A., J.W. Hopmans, B.R. Hanson, and J. `imunek. 2004. Two-dimensional modeling of Nitrate Leaching for Different Fertigation Strategies under Micro-Irrigation. In Press. Agricultural Water Management. Hanson, B., J.W. Hopmans, J. Simunek, and A. Gardenas. 2004. Crop nitrate availability and nitrate leaching under micro-irrigation for different fertigation strategies. Transactions of ASAE. Lamm, F. R. 2004. Comparison of SDI and Simulated LEPA Sprinkler Irrigation for Corn. In Proc. Irrigation Assn. Intl. Irrigation Technical Conf., November 14-16, 2004, Tampa, FL. Available from Irrigation Assn., Falls Church VA. Lamm, F. R., A. J. Schlegel, and G. A. Clark. 2004. Development of a Best Management Practice for Nitrogen Fertigation of Corn Using SDI. Appl. Engr in Agric. 20(2):211-220. Lamm, F. R. and T. P. Trooien. 2003. Subsurface drip irrigation for corn production: a review of 10 years of research in Kansas. Irrig. Sci. 22(3-4):195-200. Lampinen BD, Shackel KA, Southwick SM, Olson WH, DeJong TM. 2004. Leaf and canopy level photosynthetic responses of French prune (Prunus domestica L. French) to stem water potential based deficit irrigation. Journal of Horticultural Science & Biotechnology 79:638-644. Lakso, A.N. 2003. Water relations of apples. P. 167-194. In: Apples: botany, production and uses. D.C. Ferree and I.A. Warrington (eds.), CAB International, Wallingford, Oxon, UK. Lakso, A.N., D.M. Eissenstat, L. Comas and R. Dunst. 2003. Effects of Irrigation and Pruning on Concord Grape Productivity and Seasonal Root Development. International Water and Irrigation 23 (2)32-34. Li, K-T., A.N. Lakso, R.M.Piccioni, and T.L. Robinson. 2003.Summer pruning reduces whole-canopy carbon fixation and transpiration in apple trees. Journal of Horticultural Science and Biotechnology 78:749-754. Lesikar, B.J., V.L. Weynand, and R.A. Persyn. 2004. Evaluation of the application uniformity of subsurface drip distribution systems. Proceedings of the 10th National Symposium on Individual and Small Community Sewage Systems. American Society of Agricultural Engineers. March 21-24, Sacramento, California. Rogers, D. H. and F. R. Lamm. 2004. Key considerations for a successful subsurface drip irrigation (SDI) system. In proceedings of the Central Plains Irrigation Conference, Kearney, NE., Feb. 17-18, 2004. Available from CPIA, 760 N.Thompson, Colby, KS. pp. 87-92. Martin, E.C. and M.K. ONeill (ed). 2004. Fourth Annual Four Corners Irrigation Workshop. July 10-11, 2003. Shiprock, NM. University of Arizona Technical Report. 51p. http://cals.arizona.edu/pubs/water/abe001.pdf

Impact Statements

A 40-acre ($40,000) Kansas SDI system (Randy Leckron, farmer) was remediated from a 40% plugged and near failure condition to reclamation of 90% of design capacity. This case study has also been used in educational meetings to alert other producers, designers, and installers to help minimize and prevent problems.
Preliminary results indicate that SDI frequency does not affect corn yields in the High Plains climate and for the predominate soils of the region. These results will allow for simpler, less expensive system designs and management schemes.
Improved design and management information is available for using SDI technology for application of livestock lagoon wastewater. Current data indicate that standard heavy wall drip tubes could be used to apply effluent rather than higher cost wastewater tubes with initial cost savings of $1000 to $1300 per acre.
Results in the Texas Panhandle indicate that SDI uses water more efficiently than other irrigation technologies for grain sorghum and cotton under deficit irrigation (50% or less of full ET), which is common in the Central Plains region due to declining well yields. This is a critical consideration for irrigation system selection and design.
Carl Grooms Strawberry grower, Plant City FL: Drip uses less water, does not wash beneficial crop chemicals off of the foliage, (reducing chemical applications); and results in lower disease incidence than sprinkler.
Field experiments so far indicated that watermelons can be grown with one or two driplines per row even under the very shallow soils. These results will allow more efficient and less costly microirrigation system design for watermelon.
The Whole Oregon carrot industry is switching to drip for higher yield and lower incidence of plant disease.
A modeling study in CA has led to a Cooperative Extension Manual that will be available early 2005. This report will address issues and provide guidelines for fertigation practices, minimizing adverse environmental impacts.
Many almond and prune growers in CA are using plant-based measurements (midday stem water potential) for irrigation monitoring/scheduling, and of these, most are employing RDI to improve the horticultural performance of their crop. A web search under the keywords almond RDI and irrigation, resulted in 70 hits, including a number of commercial sites (e.g., http://pmsinstrument.com/links.htm). Much of the information available on these sites is based on work done as part of W-128.
The benefits of RDI have been presented to over 500 almond and prune growers at statewide meetings, regarded by most as a reliable source of accurate and up-to-date information.
Work on the W-128 project led to Iowa Fruit and Vegetable Growers Association providing $12,000 (over 3 years) to develop optimum irrigation scheduling to maintain continuous growing season bell pepper production.
Citrus growers representing over 2000 acres of citrus have started using soil water probes to manage their irrigation systems. This allows them to make improved irrigation decisions, reduce deep soil percolation, and save water.
W-128 citrus irrigation management research has shown that citrus growers should be able to reduce irrigation by about 10% in the winter without negative effects. Pumping costs can be reduced by $12/acre/year, which can mean a savings to the Florida citrus industry of $8 million/year.
Most Louisiana strawberry farmers have adopted drip irrigation under plastic mulch and are learning to use scheduling to improve their management of water and fertilizer applications. Research to date has not supported the adoption by Louisiana farmers of SDI in cotton or micro-sprinklers in sweet potatoes.
Research on irrigation needs and amounts in NY has led to increases in microirrigation by apple and grape growers in NY and the Northeast US. Irrigation of white winegrapes has helped several wineries in NY avoid a drought-stress related wine defect.
Subsurface drip irrigation of septic tank effluent is showing promise as being an environmentally friendly alternative to century-old gravity percolation trench technology. This new method achieves higher pollution removal rates and better reuse of wastewater nutrients by plants.
A drip irrigation workshop for hybrid poplar tree production was provided at the fifth Annual Four Corners Irrigation Workshop. July 15-16, 2004. Durango, CO.
Over 150 farmers/irrigators in CA attended a workshop on microirrigation system distribution uniformity (DU). Average system DU values increased 10 percentage points between the first and second measurement seasons.
CA Dept of Water Resources personnel and major irrigation designers/dealers in CA are more aware of microirrigation system design and management problems that lead to poor distribution uniformity.

Date of Annual Report: 11/05/2005

Report Information

Annual Meeting Dates: 11/02/2005 - 11/04/2005
Period the Report Covers: 10/01/2004 - 10/01/2005

Participants

Daugherty, LeRoy A., Administrative Advisor (ldaugher@nmsu.edu) - New Mexico State University; Rein, Bradley (brein@csrees.usda.gov) - CSREES Representative; USDA-CSREES: Stanley, Craig D (cds@ifas.ufl.edu) - University of Florida; Clark, Gary, Vice Chairman (gac@ksu.edu) - Kansas State University; O'Neill, Mick, Secretary (moneill@nmsu.edu) - New Mexico State University; Alam, Mahbub (malam@ksu.edu) - Kansas State University; Arancibia, Ramon A. (raranci@uvi.edu) - University of the Virgin Islands; Bartolo, Michael (avrc@coop.ext.colostate.edu) - Colorado State University; Colaizzi, Paul (pcolaizzi@cprl.ars.usda.gov) - Conservation & Prod. Res. Lab USDA-ARS; Lamm, Freddie R. (flamm@oznet.ksu.edu) - Kansas State University; Parsons, Larry R. (lrp@lal.ufl.edu) - University of Florida; Porter, Dana O. (d-porter@tamu.edu) - Texas A&M University; Rogers, Danny (drogers@ksu.edu) - Kansas State University; Roman, Elvin (eroman@uprm.edu) - University of Puerto Rico; Sammis, Ted (tsammis@nmsu.edu) - New Mexico State University; Schwankl, Larry J. (schwankl@uckac.edu) - University of California Davis; Shackel, Ken A. (kashackel@ucdavis.edu) - University of California Davis; Shock, Clinton C. (Clinton.Shock@oregonstate.edu) - Oregon State University; Taber, Hank G. (taber@iastate.edu) - Iowa State University; Yitayew, Muluneh (myitayew@u.arizona.edu) - University of Arizona; Calvo, Raul (sanchezr@purdue.edu) - Purdue University; Carrillo, Guillesmo (gcarrillo@purdue.edu) - Purdue University; Pereira, Andre (andre.pereira@oregonstate.edu) - Oregon State University;

Brief Summary of Minutes

A detailed version can be found at http://www.cropinfo.net/W-128/w128.html

November 02, 2004

Opening: 8:00 a.m. on Wednesday, November 2, 2005 at the Amerisuites Hotel in Phoenix, AZ. Members introduced themselves and minutes from the 2004 meeting in Tampa, FL were discussed and approved.

LeRoy Daugherty distributed 2004 W1128 reports and formats for the 2005 Annual Report. The National Information Management and Support System (NIMSS) Website was highlighted. The NIMSS URL for W1128 is: http://nimss.umd.edu/homepages/home.cfm?trackID=5254. The Annual Report format can be found for W1128 at http://nimss.umd.edu/homepages/saes.cfm?trackID=5254. He also highlighted proposed reduction in the USDA budget which calls for moving funds from formula-based to competitive grants. There will probably be an increase in funding for priority areas such as water and natural resources research.

Brad Rein first CSREES liaison from Washington. Works in the Plant Animal Systems Unit. The RFA for NRI has a section for water & watersheds (see http://www.csrees.usda.gov/funding/rfas/pdfs/06_nri.pdf. The Small Business Innovative Research (SBIR) program, found at http://www.csrees.usda.gov/funding/sbir/sbir.html, encourages working with reasonable ideas from small businesses. Other Websites of interest to SBIR for funding opportunities can be found at http://www.csrees.usda.gov/funding/sbir/sbir_interest.html

State Reports

1) Gary Clark KSU: Three projects: 1) tapered drip lateral design, 2) microirrigation of popular trees with livestock lagoon waste water, and 3) chlorine dosing in diverted waste water. Poplar trees planted in large containers with capabilities to collect leachate. Trees grew better with lagoon water but there was a build up of salts. Other observations: nitrogen increased in the leaves; SAR was up to 2.1 in June 2005; growth was enhanced but salt problem.

2) Larry Schwankl UC-Davis: Two projects: 1) iron clogging of drip irrigation systems. Growers dump well water into ponds to settle out heavy iron load. 2) Irrigation of raisin grapes. Experimenting with a new trellis system using second year wood on an alternate trellis. Research is required to find a balanced water application strategy for alternate vines with different water requirements.

3) Freddy Lamm KSU: Passed out paper of KSU outputs. The URLs are: http://www.oznet.ksu.edu/sdi/Reports/document.htm and http://www.oznet.ksu.edu/sdi/Photos/Photos.htm. Two experiments: 1) emitter flow rate for soil water redistribution. Better lateral movement & wetting of soil surface after several rainfall events. 2) Emitter spacing & water redistribution. At the 2 ft spacing, water was moving more uniformly parallel then perpendicular to the line. At the 4-ft spacing, water was not getting all the way between emitters.

4) Ken Shackel UC-Davis: Current practices calculate reference ET based on the same dataset but use different calculations. A common method for calculating ET must be utilized by W1128; will report on a daily time step basis. Required data for reference ET calculations are: radiation, temperature, wind speed, and humidity. ET is based on surface area, consequently express results on total surface area regardless of wet and dry areas. A breakout session to follow.

5) Hank Taber ISU: Two experiments: 1) irrigation scheduling with bell pepper. The 2004 was a perfect year for peppers but not so for 2005. Two treatments to schedule irrigation. Both systems were satisfactory in 2004 but the tensiometer treatment was not as productive in 2005. 2) The pre-sidedressed soil nitrate test (PSNT) was used to correlate NO3-N in top 30 cm of the soil profile. There was an N response in 2004 but not in 2005. It appears to be site or year specific.

6) Tom Thomson UofA: Encouraging adoption of SDI by AZ farmers. SDI is installed on about 25,000 acres. Very important in melon production. Driving adoption includes: 1) increased water cost - $40.00/acre-ft; 2) decreasing availability of water drought & reallocation to tribes; and 3) improved yield & quality. High initial costs, increased management demand, and uncertainty of land ownership have limited adoption. UofA has a web site documenting a large scale demonstration at the Maricopa research center at http://cals.arizona.edu/azdrip.

7) Mick ONeill NMSU: Research on corn ET and N requirements under large scale SDI production systems. Gophers continued to plague the project. Work continued on surface drip irrigated hybrid poplar research. The clones OP-367 and 311-93 are most adapted to the region. Future direction will concentrate on surface drip with hybrid poplar. The SDI corn research will be discontinued.

8) Dana Porter TAMU: Several SDI projects are scattered through the state of Texas: 1) Helms Farm - recently acquired 373 acre using 86 acres for SDI. Out reach efforts on web: http://lubbock.tamu.edu/cotton. 2) Dawson County - large scale cotton variety test; 20 acre, 8 research projects with 22 zones, individually metered, at the filters house.

Business Meeting: Review of collaborative process look at milestone. Accomplishments & Impacts to be developed around milestones. The following are Milestone Leaders who will coordinate the annual report. MS-1, Lamm; MS-2, Clark; MS-3, Hill; MS-4, Yitayew; MS-5, Lamm; MS-6, Schwankl; MS-7, Shackel; MS-8, Tabor; MS-9, Shock. State summaries and intermediate results can go on the website as a Word document or a PowerPoint presentation.

November 03, 2005

9) Ramone Arancibia UVI: Inherited trials from predecessors: 1) studies on banana using tensiometers; and 2) studies on pepper using a fixed irrigation schedule. No differences in the banana trial. Too much rain & 100% viral infection in the pepper trial. UVI will change to tomato in 2006 and look at ornamentals in water catchments.

10) Mike Bartolo CSU: Concentrating drip with high value crops. Using GPS-guided tractors and other specialized equipment. The city of Aurora recently purchased 3,000 ac-ft of Arkansas River water to exchange saline well water for good quality surface water. Mapping salinity with an EM-38. Also doing drip on corn. Irrigating/furrow like the grower. Using watermarks and a weather station network.

Discussion: AZ, FL, CA & HI did work on chemistry of water for specific problems but those people are now retired. Some documentation includes: KS water quality assessment guidelines for SDI and state water quality map; CA Chemigation guideline. An urgent need to organize information and URLs for chemical guidelines. A 1-page check list of initial questions to ask the system installers should be developed.

11) Ted Sammis NMSU: Hybrid poplar clone OP-367 expanded to a large-scale plantation. Weed control is a major issue. Research to determine water-use and scaling factors for hybrid poplar grown under incomplete cover. An OPEC covariance system, an inexpensive meteorological system (~ $5,000), was used. Results were similar to those found in the literature, e.g. 30% cover = 0.6 and about 70% cover = maximum ET.

Business Meeting Continued: W1128 researchers must complete sections for 2005 Annual Report and forward to secretary. Dana Porter elected as new officer. San Antonio selected for 2006 annual meeting to precede the IA meeting; Nov 1-3 with tour on Nov 3. Dr. Porter will act as local coordinator.

12) Raul Sanchez Purdue: Presently on sabbatical at Purdue. Working on hosting an international microirrigation meeting in Spain in 2007 or 2008. Dates to be decided in the spring of 2006. Time factor discussion: 2008 is more realistic than 2006 or 2007.

13) Larry Parson UF: Florida starting to use highly treated, reclaimed water for irrigation. Agriculture is the primary user followed by residential, golf courses, and industrial power plants. Using the ECH2O sensors to monitor moisture in sandy Florida soils. They work well under perfect conditions but fertigation affects readings; reliability in the field is questionable.

Discussion: All TDR probes are sensitive to salinity (e.g. fertilizer). The Irrigas probe is good in sandy soil. The Acclima probe is low cost @ $200.

14) Paul Colaizzi USDA-ARS: The Ogallala aquifer is the main water source for agriculture & livestock in the Texas panhandle. Results with grain sorghum can be found in Trans. ASAE 47 (5) 2004. Barriers to adoption include: capital investment, cracking Pullman clay soil, and increased management with permanent beds. All the USDA-ARS Bushland information is at http://www.cprl.ars.usda.gov/index.htm.

15) Mahbub Alam KSU: SDI survey carried in the summer of 2005. There are about 20,000 acres of SDI in Kansas. Research with SDI started in 1989. A major problem is plugging from iron slime caused by CaCO3. Most users in are the 51-200 acre range and the majority of respondents were satisfied with SDI. Problems include filtration, rodents, and gophers.

16) Clint Shock OSU: Crops include forages, grains, native plants for seed, onions, and hybrid popular (see http://www.cropinfo.net). Working with various drip tape and bed configurations for potato. Nicer crops with drip on flat beds than furrow. Are differences in the potatoes are due to the irrigation system or soil temperature differences? Collaboration with NASA to automate control systems and probes. Information about the NASA Sensor Web can be found at http://sensorwebs.jpl.nasa.gov.

Business Meeting Continued Collaborative Efforts

Ken Shackel ET collaborations: Penman Monteith used as standard; documentation in ET folder sent by Ken - PMday.xls. Required data: latitude, elevation, solar radiation, max/min temps, relative humidity or dew point, wind speed. The symbols ETo and ETr are commonly used for equations that estimate ETref for 0.12 m tall, cool-season grass and 0.5 m tall alfalfa. The subscript s was added to indicate that the ASCE-EWRI (2004) standardized equations were used. ETos and ETrs give ETref rates similar to ETo and ETr, respectively. The PMday.xls application program calculates ETos and ETrs from daily weather data. Documentation for the Daily Reference Evapotranspiration (ETref) Calculator can be found in the User's Guide for PMday.xls at:
http://biomet.ucdavis.edu/evapotranspiration/PMdayXLS/PMday.htm. Should look at both ETos and ETrs. The UC-Davis site http://biomet.ucdavis.edu has links to the above calculator and other valuable ET information.

KSU Survey development: Must run any survey through a committee at the respective universities (IRB). There are many issues the touch on privacy. There was a question regarding the inclusion of location data, i.e., zip code. The IRB groups at universities can help with this question and the overall survey development. KSU has a web tutorial at http://www.k-state.edu/research/comply/ibc/training/ of what is entailed in surveys to maintain privacy & legal requirements.

November 04, 2005: Field Trip

Sundance Farms and Arizona Drip (http://www.azdrip.com/) is owned and managed by Howard Wuertz who switched to SDI over 20 years ago. Tape is deep enough to allow equipment to run over and between lines without damage. They are growing cotton, wheat, barley, watermelon, broccoli, and other crops. Mr. Wuertz has also developed conservation equipment. Sundance Farms now has 2,500 SDI-irrigated acres. We next visited the farm of John Chernicki. Doing contract research on several crops. Expressed concern that the price of water (~ $41/ac-ft) might increase thereby reducing the ability of agriculture to survive in the area. We then visited the UofAs Maricopa Agricultural Center and the USDA-ARS facility housed at Maricopa. Areas of research include aquaculture, cotton, irrigation, specialty crops, and entomology. Dr. Muluneh Yitayew demonstrated a bubbler system for irrigating trees. Dr. Tom Thompson demonstrated his large scale research project that focuses on drip irrigation and fertigation of vegetable crops.

Accomplishments

A) Milestones 1) Develop pilot survey instrument in cooperation with extension personnel. CSU: A survey questionnaire has been developed at the Arkansan Valley Research Center to determine drip irrigation acreage, practices and problems in the Patterson Hollow Watershed. The study is sponsored by the East Otero Conservation District and funded by the EPA through the Colorado Department of Public Health and Environment. Its purpose is to assess drip irrigation in the Patterson Hollow Watershed and develop Best Management Practices to minimize potential water quality impairment associated with leaching of salts, nitrates, and selenium. KSU: Kansas State University developed and implemented a survey of SDI users in the state of Kansas. The responses were for fields covering approximately 8000 acres. Approximately 63% of the systems had been installed since 2000. It had been anticipated that crop germination might be a major expressed problem since the Central Great Plains region had been in an extreme drought from 2000-2003. However only about 5% indicated germination was an important problem in Kansas. Conversely, over 75% of the respondents were concerned about rodents. Further follow-up survey work is planned at KSU. Colorado State University is planning to implement a survey in the near future. Both surveys were discussed at the W1128 annual meeting and suggestions for improvement were made. TAMU: Texas Cooperative Extension irrigation specialist and county extension agents have collaborated to develop local intensive surveys of agricultural producers using subsurface drip irrigation. While these were initiated at the local/county level, the district irrigation specialist (assisting all these agents) assisted in coordinating these single-county assessments into multi-county efforts. TAMU: Texas Cooperative Extension and Texas Agricultural Experiment Station faculty have drafted a pilot survey to include irrigation (including SDI) and agronomic practices of producers in the Texas South Plains region. This survey will be conducted in winter and early spring 2006, in conjunction with county program committee activities and regular agricultural producer education events (CEU activities). 2) Progress reports on buried and surface positioned tubing flow rates, filter performance, and treatment practices with wastewater. UC-Davis: This past year a study, entitled "Modeling subsurface drip application of onsite wastewater treatment effluent," was initiated. The fate of pollutants from subsurface drip irrigation of septic tank effluent has been studied in soil-filled containers at the UC Davis Wastewater Treatment Plant. Data from the container tests are presently being used to refine a model (Hydrus 2D) that will predict the adsorption and biodegradation of pollutants in the soil. Initial results with the model have shown that a system designed for efficient irrigation generally minimizes annual nitrate percolation. It has also shown that nitrification and denitrification rates in the soil profile were enhanced when effluent was applied in a brief daily pulse rather than continuously. While this project continues, a companion project related to pretreatment of the effluent using paracetic acid will be initiated in 2006. KSU: Lab tests conducted to evaluate treatment requirements for using livestock lagoon wastewater with drip irrigation systems found that treatment chemistry was similar to municipal wastewater; however livestock lagoon wastewater ammonia concentrations were much higher. High ammonia concentrations result in a high chlorine demand for treatment to kill bacteria. Required chlorine amounts to kill bacteria were decreased when lagoon water was treated with acid to reduce pH to 2.0. Results of this work will be used to develop maintenance guidelines for drip systems that are used to apply wastewater. KSU: Livestock lagoon wastewater was discharged through four different subsurface drip irrigation (SDI) lateral types for two summers with a total run time of 260 hours. Two of the tube products were designed for use with wastewater while the other two were not. All four had relatively high flow (4L/h) emitters and all maintained consistent lateral discharge throughout both summers. 3) Obtain dripline products and filters for lab tests, field tests and analyses. UC-Davis: This past year we initiated a project comparing disc and screen filters for removing algae from surface irrigation water. Its goal is to objectively evaluate disc filtration for removal of algae (Spirogyra) and to compare its performance with that of screen filters. For our preliminary tests, three mesh sizes (80,120,155) were evaluated in the laboratory with different algal loading rates. Our initial observations indicate that the clogging characteristics of disc and screen filters are different. Clogging in a disc filter proceeds in a linear fashion, whereas, for a screen filter, clogging proceeds very slowly at first, but rapidly increases once a level of contaminant forms on the screen surface. Overall, the disc filter is more efficient in filtering the algal contaminated water. The time and suspended solids retained on a disc filter for a predetermined pressure drop are both more than twice that of a screen filter. Removal of the impurities of the disc filter is also more efficient than it is on a comparable screen filter. Our laboratory research will continue, before initiating a field study this next year. 4) Develop and finalize protocols for evaluation of subsurface dripline and filter installations. UA: Field data collected on soil water content from a subsurface drip irrigated field was analyzed to see the possibility of using water content to evaluate uniformity of water application by subsurface drip system. Normal statistical and geostatistical methods were applied to analyze the relationship between soil texture and water content distribution. Pressure and discharge measurements were also used to evaluate uniformity of the subsurface drip system. The preliminary result shows a good agreement between uniformity based on soil water content and ones based on discharge and pressure. 5) Conduct studies on effect of dripline depth and dripline placement. KSU: A research study at Kansas State University (KSU) has indicated that dripline depths ranging from 0.2 to 0.6 m are acceptable for corn production on silt loam soils in situations where crop germination is not a factor. Further studies are being conducted with soybean and sunflower. Preliminary results from a silt loam soil water redistribution study at KSU are indicating water movement parallel to the dripline is greater than perpendicular movement for emitter spacings ranging from 0.3 to 1.2 m. Further work is needed to determine if these distribution differences are permanent or transient and being related to the recent system installation. TAMU: In the spring of 2005 a new SDI system was installed at the Lamesa Cotton Growers AgCARES research farm in Dawson County, Texas. This site includes multiple tape spacing (every row and alternate furrow spacing). The Amarillo fine sandy loam soil at this site provides an excellent complement to the clay loam soils at another location (Hale County, Texas) for evaluation of SDI lateral spacing, soil profile moisture distribution, and crop germination issues. The Dawson County SDI system will be the focus of acid injection, variety, nutrient management, IPM, and irrigation capacity studies. The USDA-ARS in Bushland, TX is evaluating the effectiveness of different bed-lateral designs and lateral depths for crop germination. The first successful season of soybeans was completed in 2005. Germination and crop yield data are presently under analysis. 6) Conduct mitigation of iron clogging field tests. UC-Davis: California completed field tests on 5 chemicals to mitigate the impacts of iron clogging in drip irrigation systems. Iron clogging is a significant problem in some areas using groundwater for irrigation. Iron is a naturally occurring constituent in some groundwaters. When desolved iron exposed to air begins to precipitate and settle out of the water. Four of the chemical products tested, all commercially available, were phosphonate / phosphonic acid products. Two sites (drip irrigation on winegrapes) with problematic iron levels (one site at 4 ppm and one at 18 ppm iron) were evaluated. At both iron levels, the phosphonate / phosphonic acid products were effective in mitigating iron clogging of emitters. In addition, a pond used for aeration / settling of precipitated iron (20 ppm in source well) was also evaluated. The pond was effective in reducing the iron levels to 5-8 ppm in the pond discharge water. 7) Agreement and standardization of data requirements and format guidelines for evaluation of ET scheduling procedures (MS Excel format). UC-Davis: The participants of W1128 agreed to use both short and tall crop reference evapotranspiration (ET) values (ETos and ETrs, respectively) as estimates for evaporative demand, and to express all quantities of applied water, rain and ET as equivalent depth units (mm or inches) over the entire area under consideration, when reporting an analyzing irrigation experiments. The ET method will be based on the standardized Penman Monteith equation from the Environmental Water Resources Institute (EWRI) of the American Society of Civil engineers (ASCE), and can be found at http://biomet.ucdavis.edu/. The participants further agreed that either daily or hourly weather data would be acceptable as inputs for the calculation of ET, and that, as far as possible, the weather data should be obtained under environmental conditions representative of the agricultural conditions under study (i.e., weather station data from a location nearby to the experimental plots). NMSU: A hybrid poplar experiment was initiated at Farmington New Mexico with the objectives of determining the water use and crop coefficient for popular under incomplete cover. In order to scale down crop coefficients from complete to incomplete cover, the experiment is designed to determine the scaling factor for the ratio of the crop coefficient (kc) to the maximum crop coefficient (kcmax). The 95-acre experiment consisted of hybrid poplar planted at a tree spacing of 12 x 12 ft. The application rate 0.05 inch/day over total area represented 0.5 inches per day based on a projected area of 10% at the beginning of the growing season. Evapotranspiration (ET) was measured using OPEC Eddy Covariance equipment. Projected area of the trees was measured using a balloon mounted camera and Photoshop software. Reference ET was determine from a near by weather station The crop coefficient, expressed by the quadratic equation y = -45,530 + 2.36x - 0.00003x2, increased from 0.2 to 0.6 where it remained until the end of the growing season. The projected area at the end of the growing season was 30%. The kcmax of 1.1 from the literature divided into a kc of 0.6 resulted in a kc/kcmax= 0.55 similar to published values for almonds of 0.6 for a projected area of 30%. 8) Conduct studies on nitrogen dynamics and efficiency. ISU: The states of IA, NM, FL, OR, and CO agreed to monitor the use of nitrogen (N) applied to various crops as, peppers (IA), poplars (NM), strawberries (FL), potatoes (OR), and onions (CO), with microirrigation management systems to understand N dynamics under each state's unique cultural system. Monitoring tools include soil ammonium and nitrate tests, plant leaf N analysis and/or SPAD measurements, leaf petiole tissue sap nitrate test, and soil water leachate nitrate and total N measurements. At least one tool will be used at all sites. Iowa, for example, will compare soil nitrate, leaf petiole sap nitrate, and leaf SPAD measurements for a commercial bell pepper crop to determine which will most accurately predict the need for a sidedress N application. Comparisons between leaf nitrogen and SPAD readings will be carried out in New Mexico. Florida will use soil water leachate nitrate and total N measurements to evaluate N fertilizer practices. NMSU: Hybrid poplar growth and development continued to be monitored in trials established in Farmington, NM during 2002 and 2003. A range of responses in height, DBH, and wood volume demonstrates the variability of clonal adaptation to growth in an arid/semi-arid environment and calcareous soil with elevated pH. Chlorosis, as measures with a SPAD meter, is evident in all clones but to varying degrees. Response to iron chelate applications is also variable with respect to clones. In order to reduce costs associated with iron chelate application, a trial was established in 2005 to compare chlorosis recovery from applications of iron chelate and composted biosolids obtained from a municipal waste-water treatment facility. SPAD readings were highest in poplar leaves for the 20-ton per acre treatment followed by the 10-ton per acre treatment, the iron chelate treatment, and the control, respectively. Analysis is underway to determine chlorophyll content of poplar leaves from the various treatments. In order to evaluate a larger population of hybrid poplar adapted to the arid/semi-arid environment of the Four Corners region, 65 clones were planted in a replicated trial during 2005. Variable responses to iron chelate applications, as determined with a SPAD meter, were expressed by the clones. 9) Conduct studies on micro-environmental differences in potato. OR: Both 'Umatilla Russet' and 'Ranger Russet' potatoes were grown using sprinkler irrigation and 4 drip irrigation layouts at 44,849 seed/ha. The three drip-irrigation configurations described below on flat beds and drip irrigation on conventional hilled beds (configuration 4) were compared with sprinkler irrigation on conventional hilled beds. The drip configuration on conventional hilled beds (configuration 4) was the least productive of the 4 treatments, which may help explain why many potato experiments with drip irrigation are often unsuccessful. All the drip configurations produced more marketable yield per applied water than sprinkler irrigation. OR: The effectiveness of alternative drip line placement in flat beds was evaluated for 'Umatilla Russet' potato in terms of yield, tuber quality, and soil water dynamics. Three drip line/potato row placements were examined (drip line installed 0.08 m deep directly over the potato rows 0.91 m apart; drip line installed 0.08 m deep between double rows of potatoes 0.4 m apart; and drip line installed at 0.08 m depth but with the drip line offset 0.15 - 0.2 m from the potato rows spaced 0.91 m apart.) Each configuration was planted at both 44,850 and 59,800 seed/ha. The soil water remained adequate all season, since the soil water potential remained in the ideal range (-30 kPa) for all drip treatments regardless of configuration. The total amount of water applied by the drip systems plus rainfall averaged only 399.5 mm, 66 percent of the estimated potato evapotranspiration (604.0 mm). The reduced water required suggests that drip irrigation is a very efficient method for applying limited amounts of water for potato production. The average yield in flat beds showed little difference caused by drip tape configuration or plant population. The high population produced significantly more 113.5- to 170-g tubers, and there was a significant year by population interaction. The lowest yield of US No. 2 tubers (an advantage) was produced by the high population in two rows per bed with drip tape above the row (configuration 1). B) Other progress not associated with milestones FL: Several moderately-priced soil water sensors are being evaluated and calibrated. Advantages and disadvantages of different sensors for use in citrus groves have been noted. Field reliability has been a problem with some sensors, but others have performed acceptably. Some sensors are influenced by fertilizer salts. FL: Tests on Hamlin and Valencia oranges show that water stress imposed in fall & winter can increase fruit brix and acid. Severe water stress caused by rainfall exclusion caused brix/acid ratio to decline and bloom date to be delayed. Growers can conserve water by withholding irrigation in fall & winter, improve solids, and not impact yield greatly. FL: Reclaimed water use continues to increase in Florida. Our tests showing that this water can be safely used has led to a 168% increase in edible crop acreage and a more than 8500% increase in residential area using reclaimed water in the past 12 years. FL: Tests continue to determine microsprinkler irrigation land area coverage needed for optimum citrus production. Four irrigation treatments of approx 25, 50, 75, and 100% of total land area coverage were established. Optimum coverage was found to be 50 to 75%. There was no advantage to 100% coverage. 25% coverage was inadequate and trees here showed greater water stress. Ambersweet orange fruit loss due to hurricanes was greater than other orange varieties. Other leveraged work not directly related to 2005 milestones Lamm, F. R. et al., Summer 2005, Deficit Irrigation Management, a special project in Ogallala Initiative, USDA Cooperative Agreement, $500,000. 2005-2009. Lamm, F.R., D.H. Rogers, L.R. Stone, and J. Peterson. Water conservation-increased efficiency in usage. Summer 2005. USDA-CSREES Special Research Grants Program. $69,449. Lamm, F. R. et al. Summer 2005, Ogallala Initiative, USDA Cooperative Agreement, $40,000 allocated to R-304. F.R. Lamm. Improved irrigation micromanagement for corn. Pioneer Hi-Bred Inc. $8,000. ONeill, M.K. and D. Smeal. 2005. Low-tech microirrigation for small-scale Navajo producers. US Department of Interior Bureau of Reclamation. $31,320. ONeill, M.K. 2005. Sub-contract to: Stanton, B. 2004.Modification of the composition and quality of hybrid poplar biomass in the Pacific Northwest. US Department of Energy. $5,000.

Publications

Refereed Publications: Clark, G. A., F. R. Lamm, and D. H. Rogers. 2005. Sensitivity of thin-walled drip tape emitter discharge to water temperature. Appl. Engr in Agric. 21(5):855-863. Enciso, J. M., P. D. Colaizzi, W. L. Multer. 2005. Economic Analysis of subsurface drip irrigation lateral spacing and installation depth for cotton. Transactions of the ASAE. Vol. 48(1): 197-204. Fares, A., P. Buss, M. Dalton, A.I. El-Kadi, and L.R. Parsons. 2004. Dual field calibration of capacitance and neutron soil water sensors in a shrinking-swelling clay soil. Vadose Zone J. 3:1390-1399. Kim SH, Shackel, KA, Lieth JH (2004). Bending alters water balance and reduces photosynthesis of rose shoots. Journal of the American Society for Horticultural Science 129:896-901. Lamm, F. R. and T. P. Trooien. 2005. Dripline depth effects on corn production when crop establishment is nonlimiting. Appl. Engr in Agric. 21(5):835-840. Morgan, K., Obreza, T., Scholberg, J., L.R., Parsons, and T.A. Wheaton. 2005. Citrus Water Uptake Dynamics on Central Florida Sandy Soils. Soil Science Society America. In press. ONeill, M.K., D. Smeal , R.N. Arnold, and K. Lombard. 2006 Growth and survival of drip-irrigated hybrid poplar in the semi-arid Four Corners region. Journal of Sustainable Forestry. In Press. Pablo, R.G., M.K. ONeill, B.D. McCaslin, M. D. Remmeng, J. Keenan. 2006 Evaluation of corn grain yield and water use efficiency using subsurface drip irrigation. Journal of Sustainable Agriculture. In Press. Shock, C.C., E.B.G. Feibert, and L.D. Saunders. 2005. Onion response to drip irrigation intensity and emitter flow rate. HortTechnology. 15:652-659. Steele, M. 2005. Assessment of chlorine dosing with livestock wastewater effluent. M.S. Thesis. Kansas State University. Abstracts, Conferences, and Proceedings: Alam, M and D. Rogers. 2005. Field Performance of Subsurface Drip Irrigation (SDI) in Kansas. In Proc. Irrigation Assn. Intl.Irrigation Technical Conf., November 6-8, 2005, Phoenix, AZ. Available from Irrigation Assn., Falls Church VA. IA Paper No. IA05-1209. http://www.oznet.ksu.edu/sdi/Reports/2005/IA05-1209.pdf. Bandaranayake, W., L.R. Parsons, M.S. Borhan, and J. D. Holeton. 2005. Performance of capacitance type ECH2O probes when estimating soil water content in a well drained Florida sandy soil. Soil Sci. Soc. America. 69th Ann. Meeting. Salt Lake City. p. 112. Borhan, M.S., L.R. Parsons, W. Bandaranayake. 2004. Evaluation of a Low Cost Capacitance ECH2O Soil Moisture Sensor for Citrus in a Sandy Soil. Irrigation Assoc. Conf. Proceedings. Pp. 447-458. Dukes, M. D., D. Z. Haman, F. Lamm, J. R. Buchanan and C. R. Camp. 2005. Site selection for Subsurface Drip Irrigation Systems in the Humid Region. Proc. ASCE-EWRI Water Congress, May 15-19, 2005, Anchorage, AK. 11 pp. Enciso, Juan, John Jifon and Bob Wiedenfeld. 2005. Subsurface Drip Irrigation of Onions: Effects of Emitter Spacing and Drip Depth on Yield. Paper number 052242, 2005 ASAE Annual Meeting. Fares, A., L.R. Parsons, T.A. Obreza, and K. Morgan. 2004. Spatial and Temporal Plant Water Use and Rain Inputs as Affected by Citrus Canopy and Microsprinkler Irrigation System. Irrigation Assoc. Conf. Proceedings. Pp. 37-45. Fares, A., M. Zekri, and L.R. Parsons. 2004. TheHelper, a User-Friendly Irrigation Scheduling Tool in Florida and Hawaii. Irrigation Assoc. Conf. Proceedings. Pp. 413-423. Heyduck, Rob, Mick ONeill, Kevin Lombard, Dan Smeal, and Rick Arnold. 2005. Hybrid poplar production for multiple benefits in the semi-arid southwest. November 7-10. Northern Arizona University, Flagstaff, AZ. Lamm, F. R. 2005. SDI for conserving water in corn production In Proc. ASCE-EWRI Water Congress, May 15-19, 2005, Anchorage, AK. 12 pp. Lamm, F. R. and R. M. Aiken. 2005. Effect of irrigation frequency for limited subsurface drip irrigation of corn. In Proc. Irrigation Assn. Intl. Irrigation Technical Conf., November 6-8, 2005, Phoenix, AZ. Available from Irrigation Assn., Falls Church VA. IA Paper No. IA05-1264. Lombard, K., M.K. ONeill, D. Smeal, R.N. Arnold, and J.G. Mexal. 2005. Hybrid poplar establishment under harsh environmental and edaphic conditions. 9th North American Agroforestry Conference. June 12-15. Rochester, MN. http://cinram.umn.edu/afta2005/pdf/Lombard.PDF. McWilliams, D. and J. Gleason. 2005. Optimizing Irrigation in New Mexico. Contributing Interviewee. Rio Grande Basin Initiative. Cooperative Extension Service and Agricultural Experiment Station. New Mexico State University. Las Cruces, NM. Noling, J.W., L.R. Parsons, & T. A. Wheaton. 2004. 2005 Florida citrus pest management guide: Best Management Practices for soil-applied agricultural chemicals. HS-185. Electronic Data Information Source. University of Florida Institute of Food and Agricultural Sciences Pub. 5 pp. O'Neill, M.K., K. Lombard, D. Smeal, R.N. Arnold, and J.G. Mexal. 2005. Opportunities for hybrid poplar production in the Four Corners region of New Mexico. 96th Annual Meeting, American Society of Agronomy. November 6-10. Salt Lake City, UT. http://crops.confex.com/crops/2005am/techprogram/P7794.HTM. Pablo, R.G., M.K. O'Neill, B.D. McCaslin, M.D. Remmenga, and J. Keenan. 2005. Corn production and water use efficiency under subsurface drip irrigation. 96th Annual Meeting, American Society of Agronomy. November 6-10. Salt Lake City, UT. http://crops.confex.com/crops/2005am/techprogram/P4362.HTM. Parsons, L.R. 2004. Changes in Reclaimed Water Use in Florida. HortScience 39(4). Pp. 855-856. Parsons, L.R. and B. Boman. 2005. Best Management Practices in Florida Citrus Production. HortScience 40(4). P. 942. Parsons, L.R. and K.T. Morgan. 2004. Management of microsprinkler systems for Florida citrus. HS-958. Electronic Data Information Source. University of Florida Institute of Food and Agricultural Sciences Pub. 7 pp. Parsons, L.R., E. Etxeberria. 2004. Effects of Reduced Fall and Winter Irrigation on Citrus Fruit Quality. HortScience 39(4). Pp. 886. Rivera, L.E. 2005. Manejo de microriego en la producción de yautía en la costa sur de Puerto Rico ("microirrigation management of tanier in the southern coast of Puerto Rico"). Sociedad Puertorriqueña de Ciencias Agrícolas. Scientific Annual Meeting. Novemebr 18, 2005. Arroyo, PR. oral presentation. Rogers, D. H. and F. R. Lamm. 2005. Key considerations for a successful subsurface drip irrigation (SDI) system. In proceedings of the Central Plains Irrigation Conference, Sterling, CO, Feb. 16-17, 2005. Available from CPIA, 760 N.Thompson, Colby, KS. pp. 113-118. Román-Paoli, E. 2005. Evaluation of soil moisture levels on growth and productivity of young citrus trees. 41th Annual Meeting.,Caribbean Food Crop Society. 10-16 July 2005. Le Gosier, Guadalupe. Román-Paoli, E. 2005. Uso de tensiómetros en la programación del microriego en aguacate. (" Use of tensiometers on avocado microirrigation scheduling") Sociedad Puertorriqueña de Ciencias Agrícolas. Cientific Annual Meeting. December 3, 2004. Arroyo, PR. Poster presentation. Román-Paoli, E., and F. Román. 2005. Evaluation of soil moisture levels on growth and productivity of young citrus trees. Proc. 41 Annual Meeting. Caribbean Food Crop Society. Shock, C.C., E.B.G. Feibert, C.A. Shock, A.B. Pereira, and E.P. Eldredge. 2005. Research using automated irrigation systems. Irrigation Association, 26th Annual International Irrigation Show, Emerging Irrigation Technology. November 6-8, 2005, Phoenix, Arizona. Conference Proceedings p. 31-39. Shock, C.C., E.B.G. Feibert, C.A. Shock, A.B. Pereira, and E.P. Eldredge. 2005. Innovations in Irrigation Automation for Crop Research. ASA/CSSA/SSSA Annual Meeting. November 6-10, 2005, Salt Lake City, Utah. Shock, C.C. 2005. Nitrogen management with drip and sprinkler irrigation. Western Nutrient Management Conference. Salt Lake City, UT, March 3-4, 2005, Vol. 6:66-71. http://cropandsoil.oregonstate.edu/nm/WCC103/2005_Proccedings/Shock%20N%20Management%20pg66.pdf Shock, C.C. 2005 Development of irrigation best management practices for potato production from a research perspective. Symposium on Best Management Practices for Nutrients and Irrigation: Research, Regulation, and Future Directions. Oregon Potato Association of America annual meeting, July 17 - 21, 2005, Calgary, Alberta, Canada. Shock, C.C. 2005. Nutrient and Water Management in United States Agriculture, Issues and Research Priorities. 45th Anniversary of Scientia Agricultura Sinica and Symposium on the Frontiers of World Agricultural Sciences, Beijing, Peoples Republic of China, November 20, 2005. Smeal, D. Z.F. Williams, M.M. West, M.K. ONeill, and R.N. Arnold. 2005. A low-cost drip irrigation system for small plots. 10th Xeriscape Conference: Adapting to Our Changing Reality. Feb 24-26, 2005. Albuquerque, NM. Extension Publications: Enciso, Juan and Dana Porter. 2005. Basics of Microirrigation. TCE Fact Sheet B-6160. Texas Cooperative Extension. The Texas A&M University System, College Station, TX. Improved Irrigation Scheduling Network Helps Make Every Inch of Moisture Count. News release Nov. 22, 2005. Texas A&M University System Agriculture Program News and Public Affairs. College Station, TX. Klauzer, J. and C.C. Shock. 2005. Growers use less nitrogen fertilizer on drip-irrigated onion than furrow-irrigated onion. Oregon State University Agricultural Experiment Station, Special Report 1062: 94-96. Parsons, L.R. 2004. Is a Freeze Likely this Winter? Florida Grower. Vol. 97(12). December. p. 26. Parsons, L.R. 2004. Unwanted Visitors. Florida Grower. Vol. 97(10). October. P. 28. Parsons, L.R. 2005. Essential IrrigationThe Right Time. Florida Grower. Vol. 98(2). Feb. p. 30. Parsons, L.R. 2005. Freeze Forecast. Florida Grower. Vol. 98(11). Nov. p. 38. Parsons, L.R. 2005. Population Boom. Florida Grower. Vol. 98(7). July. p. 29 Parsons, L.R. 2005. Predictions for the 2005 Hurricane Season. Florida Grower Vol. 98(9). Sept. p. 34. Parsons, L.R. 2005. Sensors Equal Savings. Florida Grower. Vol. 98(4). April. p. 42. Parsons, L.R. 2005. Weather and irrigation for the New Year. Citrus Industry. Vol. 86(1). pp. 16-17. Shock, C.C., R. Flock, E.B.G. Feibert, A.B. Pereira, and M. ONeill. 2005. Drip irrigation guide for growers of hybrid poplar. Oregon State University Extension Service. EM 8902 6p. Shock, C.C., R. Flock, E.B.G. Feibert, C.A. Shock, L. Jensen, and J. Klauzer. 2005. Drip irrigation guide for onion growers in the Treasure Valley. Oregon State University Extension Service. EM 8901 8p. Shock, C.C., E.P. Eldredge, and A.B. Pereira. 2005. Planting configuration and plant population effects on drip-irrigated Umatilla russet potato yield and grade. Oregon State University Agricultural Experiment Station, Special Report 1062:156-165. Shock, C.C., E.P. Eldredge, and A.B. Pereira. 2005. Irrigation system comparison for the production of Ranger Russet and Umatilla Russet potato. Oregon State University Agricultural Experiment Station, Special Report 1062:173-176. Shock, C.C., E.B.G. Feibert, A.B. Pereira, and C.A. Shock. 2005. Automatic collection, radio transmission, and use of soil water data. Oregon State University Agricultural Experiment Station, Special Report 1062:211-222. Shock, C.C., E.B.G. Feibert, C.A. Shock, A.B. Pereira, and E.P. Eldredge. 2005. Innovations in irrigation automation for crop research. ASA/CSSA/SSSA Annual Meeting. November 6-10, 2005, Salt Lake City, Utah. Shock, C.C. 2005. Nitrogen management with drip and sprinkler irrigation. Western Nutrient Management Conference. Salt Lake City, UT, March 3-4, 2005, Vol. 6:66-71. http://cropandsoil.oregonstate.edu/nm/WCC103/2005_Proccedings/Shock%20N%20Management%20pg66.pdf. Shock, C.C., E.B.G. Feibert, and L.D. Saunders. 2005. Micro-irrigation alternatives for hybrid poplar production 2004 trial. Oregon State University Agricultural Experiment Station, Special Report 1062:106-117. Texas Irrigation Scheduling Network Improves. E-Hay Weekly. November 29, 2005. Hay and Forage Grower Magazine. A Primedia Business Magazines & Media publication. News articles: Researchers Test Drip Irrigation Design And Returns. Newwaves E-letter. Newsletter of the Texas Water Resources Institute, Dec. 5, 2005. Researchers test drip irrigation design and returns. High Plains Journal. High Plains Publishers, Inc. http://www.hpj.com/resultscotton.cfm

Impact Statements

UA: Evaluating subsurface drip irrigation is one of the difficult problems for farmers. The procedure used for surface drip system is very hard to apply. If we can show and establish a procedure to evaluate uniformity of subsurface drip irrigation using an indirect method of soil water distribution, irrigation farmers as well as engineers will have a better tool to manage their systems.
UC-Davis: The results of the work have been reported on at a grower meeting (75 in attendance) in the area impacted by iron clogging problems. Grower interest in the work was significant. The information has also been transferable to numerous other geographical areas which also suffering drip emitter iron clogging problems.
UF-IFAS: An extension publication that gave an easy-to-understand irrigation schedule was developed for citrus. With this information, growers can develop irrigation management programs for all 12 months of the year for both ridge and flatwoods groves. This program improves irrigation efficiency by meeting tree water needs while preventing over-irrigation and water loss. This information is now available on the UF-FAWN weather web site.
UF-IFAS: Grove operations covering more than 3000 acres have started to use these probes and have reduced water use by more than 5%. This has resulted in a savings of more than 81 million gallons of water per year. One grove manager reported a $250,000 savings in fuel pumping costs by using recommended soil moisture probes.
UF-IFAS: The Southwest Florida Water Management District (SWFWMD) recently tightened water restrictions and reduced permitted water quantities to citrus groves by 25 to 30%. SWFWMD collected data on grower water use and found that 90% of the citrus growers were able to meet these new water restrictions. Growers were able to meet these permitted water quantities because of our IFAS irrigation scheduling guidelines and recommended soil moisture probes.
UF-IFAS: Field tests have shown that stopping irrigation from November to early March can save over two inches of water on Valencia oranges with minor effects on yield. We found a beneficial increase in fruit soluble solids (brix). Growers have expressed interest in this work as a potential way to increase fruit brix. If this practice were applied to 2000 acres, there would be a savings of 108 million gallons per year.
UF-IFAS: Reclaimed water can be safely used for edible crops and residential irrigation and helps increase aquifer levels.
KSU: Survey results indicate a significant number of SDI systems have been installed in Kansas since 2000. This is important to know as Extension specialists plan educational programs. Researchers may want to design studies to examine the rodent problem in more detail since it was the number one problem identified in a Kansas survey.
KSU: Producers can choose a dripline depth that best fits their tillage practices and climatic conditions for germination without major concerns of SDI system maintenance and other corn performance factors. If increased water movement parallel to the dripline is a permanent effect, this can be an important factor in determining the required emitter spacing and also on the effect of intermittent emitter clogging.
KSU: Drip irrigation laterals with high flow emitters can be used to apply filtered livestock lagoon wastewater without serious plugging consequences. This information along with the water treatment results will help designers and operators of SDI systems used to apply livestock lagoon wastewaters in their selection, decision, and management processes.
ISU: Crop N efficiency can be improved compared to the standard grower practice, if a monitoring tool is employed in making the sidedress N decision.
NMSU: A hybrid poplar plantation of nearly 100 acres was established on the Navajo Agricultural Products Industry (NAPI) in an effort to diversify their cropping systems. A local saw mill and a poplar plantation management company will partner with NAPI to produce woody products from sustainable sources.
NMSU: The Public Service of New Mexico (PNM) is developing bioenergy power plants that will use woody feedstocks obtained from the forest. A sustainable source of poplar biomass from nearby plantations would be highly advantageous to PNM in view of lower transportation costs associated with these production systems.
NMSU: Results from the OPEC Eddy Covariance experiment can be used to schedule irrigation for hybrid poplar with incomplete cover based on literature and the measured scaling factor function. Addition years of measurement will continue to develop the function for more complete cover as the trees grow.
NMSU: The SPAD meter is a valuable tool for rapidly determining the degree of chlorosis experienced by various hybrid poplar clones in an arid/semi-arid environment with calcareous soils and elevated pH. The use of composted biosolids can be an inexpensive strategy for providing micronutrients that may be otherwise unavailable in calcareous soils typical of arid/semi-arid regions.
OR: Observations for onion growers records showed that growers used 115 kg/ha less fertilizer N when irrigated with SDI than with furrow irrigation.
OR: Microirrigation has the potential to reduce water use, leaving more water in streams and reservoirs. Surface water contamination of streams can be less with micro irrigation and groundwater contamination by nitrate and pesticides can be sharply lower.
OR: The environmental benefits of microirrigation can only be achieved if micro irrigation proves to be economically feasible through reductions in other costs not related to the added costs of the micro irrigation system and improvements in crop yield or quality.
OR: Drip-irrigated onion has expanded to about 5,000 acres in the Treasure Valley and above 10,000 acres in the Pacific Northwest. There were 2,300 acres in Malheur County, with vastly reduced N inputs and no irrigation-induced erosion and associated pollutant runoff. Thirty to 40 percent less water was required using SDI.

Date of Annual Report: 01/03/2007

Report Information

Annual Meeting Dates: 11/01/2006 - 11/03/2006
Period the Report Covers: 10/01/2005 - 09/01/2006

Participants

Daugherty, LeRoy, (ldaugher@nmsu.edu) Administrative Advisor - New Mexico State University; Rein, Bradley (brein@csrees.usda.gov) CSREES Representative - USDA-CSREES; Clark, Gary (gac@ksu.edu) Chairman - Kansas State University; O'Neill, Mick (moneill@nmsu.edu) Vice Chairman - New Mexico State University; Porter, Dana (d-porter@tamu.edu) Secretary - Texas A&M University; Arancibia, Ramon (raranci@uvi.edu) - University of the Virgin Islands; Berrada, Abdel (Abdel.Berrada@Colostate.edu) - Colorado State University; Braden, Chris (cbraden@ag.tamu.edu) - Texas A&M University; Fares, Ali (AFares@Hawaii.edu) - University of Hawaii at Manoa; Howell, Terry (tahowell@cprl.ars.usda.gov) - USDA-ARS Conservation & Production Research Lab; Neibling, Howard (hneiblin@uidaho.edu) - University of Idaho; Schwankl, Larry (schwankl@uckac.edu) - University of California at Davis; Shackel, Ken (kashackel@ucdavis.edu) - University of California at Davis; Shock, Clinton (Clinton.Shock@oregonstate.edu) - Oregon State University; Stanley, Craig (cds@ifas.ufl.edu) - University of Florida; Taber, Hank (taber@iastate.edu) - Iowa State University

Brief Summary of Minutes

The meeting opened at 8 am Wednesday, Nov 1, 2006 at the Best Western Sunset Suites Hotel in San Antonio, TX. Attendees introduced themselves. Dr. Chris Braden (Texas A&M Irrigation Technology Center) presented itinerary for the technical tour for Friday, Nov 3. Chair Clark presented the meeting agenda.

Comments from Administrative Advisor Leroy Daugherty: Dr. Daugherty provided guidance in addressing project milestones in annual reports. He discussed issues of federal funding and provided a position statement rationale for formula fund distribution. Dr. Daugherty addressed proposed changes in USDA to bring CSREES, ARS, and ERS together administratively for efficiency. This would represent a change in the Farm Bill. The proposal is accessible at www.create-21.org/. Dr. Daugherty indicated integrated projects are viewed more favorably. The Create-21 proposal is supported by Experiment Station leaders. Loss of formula funding would impact state funds, as much state funding is used for matching grants. Create-21 addresses accountability and standardization.

Chair Clark reviewed coordination of objectives, outcomes and milestones for 2006. Pilot instrument and survey milestone is progressing satisfactorily; survey will be adapted for use in additional states in 2007. Buried and surface positioned tubing flow rates, filter performance, and treatment practices with wastewater milestone is progressing satisfactorily. Activity toward standardized laboratory testing apparatus for dripline products has been redirected; Dr. Lesikar provided items. Subsurface installation issues coordinators will be contacted for more information. Dripline depth and placement issues are being addressed. Work on mitigation of iron clogging is ahead of schedule. ET and irrigation scheduling: Dr. Shackel is compiling information provided by participants to standardize reporting of water application and water demand (ETr and ETo). He demonstrated http://biomet.ucdavis.edu/, ET spreadsheet and data requirements. Discussion followed about representative irrigated areas for trees, ornamentals without closed canopy. N dynamics and efficiency (and other nutrient issues) are being addressed in IA, CO, FL, and other states. Contributors include Taber, Stanley, Berrada, and ONeill. Microenvironment and potato are addressed in OR and ID state reports.

Milestone assignments for 2007-2008 were discussed. Chair Clarks proposed categorization of tasks and milestones to facilitate reporting was well supported. Categories, coordinators and objective assignments: microirrigation survey (Rogers, Lamm; Obj. 1); system design and hydraulics (Clark; Obj. 2) crop production issues, including dripline placement, system installation and performance (Colaizzi, Lamm; Obj. 2); ET and irrigation scheduling (Shakel; Obj. 3); nutrient dynamics (Taber; Obj. 3); and soil microenvironment effects (Shock; Obj. 3).

Chair Clark said the new microirrigation book is available, and is an excellent reference. All agreed Dr. Lamm is to be commended for contributions.

Ken Shackel and Larry Schwankl were appointed to the nominating committee.

Comments from CSREES representative Brad Rein: Dr. Rein distributed materials discussing CSREES programming, staff, and competitive grants. Dr. Rein highlighted priorities for 2007; projects must address social issues and barriers. Water is a key topic. Referencing the national integrated food safety initiative, he posed the question, Can SDI help to reduce risk of food-borne illness? He advised applicants to allow extra time for the new electronic application process.

2007 meeting will be in Oahu, HI, Oct. 10-12, 2007.

Minutes from 2005 annual meeting were approved. Thanks were extended to Dr. ONeill for assembling the 2005 annual report; Dr. Porter for making local arrangements; Dr. Lesikar for paying for the meeting room and refreshments; Dr. Shock for maintaining the W-1128 website; and Dr. Clark for leadership in the project and meeting.

Dr. Daugherty reviewed the official list of project participants (App. E).

Agenda items for the 2007 meeting: Reports will focus on milestone progress. Coordinators will give progress reports. Products due in 2009: guidelines for design and management of SDI wastewater systems; handbook on maintenance of microirrigation systems; guidelines for treatment; guidelines for microirrigation of potato; progress report on removing barriers; and items needing further research. In 2007 we will address progress toward these deliverables.

A new project proposal will be due Jan 15, 2009. Fall 2008 will be devoted to writing new project. Proposal committee will be named in 2007. At the 2007 meeting, we will identify theme and proposed titles/topics.

Nominating committee recommendation of Ali Fares for secretary was supported unanimously. Officers for 2007 will be Past Chair Gary Clark; Chair Mick ONeill; Vice-Chair Dana Porter; and Secretary Ali Fares.

Follow-up and planning for next year: Participants will be asked to submit materials to milestone coordinators in August 2007. Meeting arrangements will be made by August so the meeting can be authorized. Presentations and reports from 2006 meeting can be sent to Dr. Shock for posting on the website. Dr. ONeill recommended that participants bring posters to 2007 meeting to present more information in the time available.

Accomplishments

State Reports: Hank Tabor (IA): Evaluation of PSNT, SPAD and leaf petiole sap nitrate tests for sweet bell pepper. PSNT proved to be more effective than leaf petiole sap nitrate or SPAD readings in identifying sites where additional sidedress N is necessary for optimum early pepper production. None of the methods were useful in predicting sidedress N for total seasonal yield. Craig Stanley (FL): Effectiveness of BMPs in commercial strawberry production. Evaluating water and N management under a range of soil types and grower cooperators involved using leachate collectors placed under roots (directly under drip emitter, representing worst case scenario). Grower questionnaires indicated most apply fertilizers according to university recommendations. Seasonal N losses were monitored; very little loss was observed. Soil types affected leaching. Results were very consistent. Ramon Arancibia (VI): 1) Benefit of short irrigation period during fruit development of wax jambu in the U.S. Virgin Islands. Irrigation treatments to replace 1.0X and .7X pan evaporation (EP) indicated irrigation promoted 2 fruit peaks, increasing overall yield (mainly in second cycle). 0.7EP resulted in higher WUE than 1.0EP. 2) Effects of water stress on Puerto Rican sweet pepper. Irrigation based upon tensiometer readings at 6 depth resulted in water use of 28%, 15%, 9% EP for 20, 40, 60 KPa tension. Water savings (and increased WUE) were achieved with increased allowable water stress, but lost yield resulted in excessive economic losses. Ali Fares (HI): Soil water sensor performance and software development. Evaluated Theta probe, N-probe, ECH2O probe and EnviroSCAN probe. Temperature scaling was developed for calibration of EnviroSCAN probe. Software approaches included statistics and water balance for irrigation scheduling and for predicting long range irrigation needs. Program calculates daily water balance and probability of drought; it includes irrigation methods and efficiencies, crops, historic ET, crop coefficients, and soil physical properties. Mick ONeill (NM): ETrs vs. ETos for planted poplar. Rain and irrigation applications approximated ETrs. Water application and soil moisture depletion for hybrid poplar indicated very good matching of ET-based irrigation and water uptake. Delta T soil moisture device was compared with N-probe. Dendrometer readings to measure tree trunk radial growth indicated the instruments performed well. Ken Shackel (CA): Plant and soil water measurements. Research addressed lysimeter data and pressure bomb measurements compared at irrigation rates of 50-125% lysimeter ET; stem water potential in peppers; irrigation scheduling for almond trees; RDI moderate stress during hull split vs. control (near non-stressed baseline); and automated weather data and valve controls by remote. Clint Shock (OR): Drip irrigation for native plant seed production; good results with very low levels of irrigation; reduced weed seed in native plant seed production. Performance of drip irrigated hybrid poplar clones in alkaline soil; effect of short duration water stress on onion quality; and effect of Auxigro on drip irrigated onion. Potato research: weed control; variety performance and harvest; comparison of tape flow rates; variety bulking and planting date; planting configuration and populations; comparison of drip, sprinkler and furrow irrigation; role of bed configurations and tuber microclimate. Conclusion: potatoes performed best planted in flat beds and irrigated with drip irrigation. Dana Porter (TX): SDI irrigation of cotton in a coarse textured soil (complementing related work on finer soils); cotton plant population by variety by irrigation rate (answering producer questions concerning optimal cotton production with subsurface drip irrigation); and system configuration for conducting SDI chemigation studies. Terry Howell (USDA-ARS, TX): Research conducted at USDA-ARS, Bushland, TX: relationships between tall and short reference ET values; evaluation of dripline placement; planting bed configurations (twin rows and SDI alternate furrows); SDI tape depth (15, 22, 30 cm) to address concerns of crop emergence and performance; and water balance from SDI (including rainfall runoff and soil water balance). Discussion of effective precipitation followed. Larry Schwankl (CA): Iron clogging in microirrigation. Phosphonic acid, phosphonates used continuously at low concentrations may keep iron in solution or interfere with crystal formation. Products (Microclean, Lineout, Sureflow, DripRite 3000) were field tested in 2 drip irrigated vineyards. One had 2-3 ppm iron; second had 18 ppm iron (very high concentration). All products worked well on 2-3 ppm iron water; they also worked well on 18 ppm iron water, although iron precipitation clogging at lateral ends was noted. Phosphonic acid products are effective in mitigating iron clogging problems; chlorine interferes with these products. Howard Neibling (ID): Turf grass irrigation and supplemental drip irrigation for trees; irrigation in mixed plant landscapes; and use of ET in lawn irrigation. Applications of SDI in forage, hay and pastures enhance production while protecting water quality. Extension efforts include irrigation scheduling using Watermarks and Hansen data loggers, and convenient laminated reference cards to help growers use these tools. Abdel Berrada (CO): Drip irrigation to reduce movement of pollutants in the Patterson Hollow watershed of the Arkansas River Basin. Issues include salinity, nitrate, sediment and pollutant loading exacerbated by furrow irrigation. Effects of irrigation type, scheduling, N rate, manure rate and interactions on salt and nitrate levels in the root zone. High soil EC related to high manure rates; potentially more leaching (less salt accumulation in root zone) with furrow irrigation as compared to SDI. Gary Clark (KSU): 1) Irrigation of Poplar tress with livestock lagoon wastewater. Trees grown in lysimeters were irrigated with fresh water only, fresh water mixed with wastewater, and wastewater only. Wastewater treatments resulted in higher water use and higher plant biomass, probably due to nutrient availability. Salt accumulation was higher with wastewater treatments. 2) Treatment of livestock lagoon wastewater with acid and chlorine. Greater than 1 ppm free residual chlorine is needed to minimize bacterial growth in wastewater. Acidifying wastewater to pH 2 reduced required chlorine additions. Technical tour: Sites visited included the TAMU Irrigation Technology Center Drought Simulator and Von Ormy Growers nursery. Accomplishments Accomplishments toward Milestones Pilot survey instrument The microirrigation pilot survey instrument has been used in Kansas and Colorado. It will be distributed to the other states for modification (as needed) and use in 2007. Results from multi-state survey will be compiled in 2008. Buried and surface positioned tubing flow rates, filter performance, and treatment practices with wastewater Filtration of surface water for microirrigation (D. Hills, UC Davis): Research relating disk filtration to screen filtration focused on cleaning ability and on an initial field study. Laboratory investigations focused on rotational and longitudinal movements of filters within a cleaning chamber under different water jet scenarios for removing Spirogyra algae from partially clogged screen surfaces. Results still need to be studied, but without question the disk filters were cleaned with much less water and energy than the equivalent screen filters. This investigation was later extended to the field, using surface water with natural occurring algae contaminates. The initial field results were similar to those of the earlier laboratory work with definable algal enriched water. Future plans are to analyze all the data within the next several months before proceeding further on the project. Treatment of livestock lagoon wastewater to reduce bacterial growths (G. Clark, KSU): Samples of livestock lagoon wastewater were treated acid to determine the amount of chlorine needed to achieve a free chlorine residual of 1 mg/kg. Lagoon water treated with only chlorine required 1250 mg/kg of NaOCl while lagoon water that was pretreated with acid to achieve a ph of 2 only required 173 mg/kg of NaOCl. In a following study, livestock lagoon water was again treated with chlorine both with and without the acid pretreatment. Chlorine treatments were designed to have free chlorine residuals less than 1 mg/kg, equal to 1 mg/kg, and greater than 1 mg/kg. Treated samples were plated for microbial growths and were sampled at zero, 2, 12, and 26 weeks. Bacterial populations were zero or minimal in all cases when the free residual chlorine was >1 mg/kg. Pretreatment with acid to a pH of 2 reduced chlorine treatment requirements from 2260 to 330 mg/kg of NaOCl. Characterization of wastewater subsurface drip emitters and design approaches concerning system application uniformity (Duan and Lesikar, TAMU): Efforts addressed performance of wastewater subsurface drip emitters at low and normal pressure, design approaches on wastewater subsurface drip zone concerning system application uniformity, and characterization of wastewater subsurface drip emitters. Results indicated emitter performance based on the uniformity coefficient were excellent, however tested flow rates of four emitter models tested had discrepancies to the nominal discharge rates. In evaluation of drip zone dosing cycle design factors (supply line length, operation pressure and pressure control scheme); supply line length had the least influence on the dose time required for design zone application uniformity. Standardized lab testing apparatus for dripline products Wastewater Drip Emitter Characterization (Duan and Lesikar, TAMU): Five drip tape products with different characteristics were using a laboratory-scale apparatus fitted with 10 lines of wastewater drip tubing, each 3.04 m in length. An apparatus used to determine emitter flow rates and lateral end pressures in the laboratory was modified from previous work. Each lateral was attached between a supply and return manifold system. Laterals were isolated using ball valves located before each lateral so that the same pressure gauge could be linked to each single line to measure operating pressure. To quantify the uniformity of this drip system, the catch-can method of uniformity testing was as described by both the American Society for Agricultural Engineers (ASAE) and the National Resources Conservation Service (NRCS) (ASAE, 1999). Small pieces of cotton string were attached to individual emitters to direct discharged water down into the catch cans located in a mobile catch basin. The strings were saturated before each sampling event. The water samples collected in containers were weighed on an electric balance with measurement accuracy of ±0.01 gram and converted to volume. A pressure gauge was installed on the supply manifold to allow a periodic check of the operating pressure. Crop production issues, including dripline depth and placement, system installation and performance SDI Bed Design Comparison for Soybean Emergence and Yield (Colaizzi, Evett, and Howell, USDA-ARS, TX): Crop emergence rates and soil wetting patterns were evaluated for three drip tape lateral and bed configurations, three tape depths (15, 22, 30 cm), and over a range of irrigation levels (dryland to full crop ET replacement). Results indicated that the wide bed configuration had greater plant emergence than standard bed, but bed design and tape lateral depth did not affect overall yield. Irrigation levels did affect yield. Iron clogging mitigation strategies Iron clogging in microirrigation (Schwankl, UC-Davis): Phosphonic acid, phosphonates used continuously at low concentrations may keep iron in solution or interfere with crystal formation. Products (Microclean, Lineout, Sureflow, DripRite 3000) were field tested in 2 drip irrigated vineyards. One had 2-3 ppm iron; second had 18 ppm iron (very high concentration). All products worked well on 2-3 ppm iron water; they also worked well on 18 ppm iron water, although iron precipitation clogging at lateral ends was noted. Phosphonic acid products are effective in mitigating iron clogging problems; chlorine interferes with these products. ET and Irrigation Scheduling Compilation and analysis of ET scheduling data from W-128 projects (Shackel, UC-Davis): Irrigation and weather data were compiled and analyzed begin to standardize reporting of water application and water demand (ETr and ETo). Daily reference ET values were calculated using the Biomet spreadsheet (available at http://biomet.ucdavis.edu/). Using these tools, irrigation treatments, ETrs and ETos based on daily weather data inputs, were compiled for various experiments for the 2005 crop season. States participating (and crops included) in this effort were California (almonds), Colorado (field corn and onion), Florida (magnolia), Hawaii (sweet corn, vegetables), Idaho (potato, turf), Kansas (field corn, soybean), New Mexico (poplar, pecan), Oregon (potato, onion), and Texas (cotton). Plant and soil water measurements (Shackel, UC-Davis): Research addressed lysimeter data and pressure bomb measurements compared at irrigation rates of 50-125% lysimeter ET; stem water potential in peppers; irrigation scheduling for almond trees; RDI moderate stress during hull split vs. control (near non-stressed baseline); and automated weather data and valve controls by remote. Nitrogen dynamics and efficiency Comparison of the sidedress N management tools (Taber, IA): Comparison of soil NO3-N test (PSNT), leaf petiole sap NO3-N, and leaf SPAD (chlorophyll meter) indicated that for bell peppers grown in IA that the PSNT was superior to the other two in identifying sites responsive to additional N. Fields with a soil NO3-N concentration > 20 ppm, at the initial flowering stage of growth, did not require additional sidedress N for optimum yield. N management in commercial strawberry production (Stanley, UFL): Results from the second year of a 4-year study to monitor, by passive wick leachate collectors, seasonal nitrate-N losses in leachate from commercial microirrigated strawberry showed that nitrate-N losses ranged from 20 kg/ha (~13% of applied N) to < 1 kg/ha depending on irrigation management intensity. The majority of the twenty-one sites had nitrate-N losses below 5 kg/ha or < 3% seasonal losses. Use of SPAD meters to monitor symptoms of leaf chlorosis (ONeill, NM): Since 2003, the SPAD meter has been used to monitor symptoms of leaf chlorosis resembling Fe deficiency in test plots of hybrid poplar at the Agricultural Science Center, Farmington. The soils are typically elevated in pH and contain variable carbonate levels that interfere with micronutrient solubility and plant uptake. The SPAD meter was used to evaluate Fe-deficient chlorosis exhibited by two hybrid poplar clones grown in the greenhouse and compared to chlorophyll a, b, and Beta-carotene extracted from leaf disks. SPAD values correlated highly with pigments and foliar elements though responses varied between hybrids and soil treatments. Based on the total chlorophyll content, SPAD calibration numbers were determined for each hybrid. Soil micro-environmental effects and microirrigation of potato Soil micro-environmental effects and microirrigation of potato (Shock, OR): Potato research activities included weed control; variety performance and harvest; comparison of tape flow rates; variety bulking and planting date; planting configuration and populations; comparison of drip, sprinkler and furrow irrigation; role of bed configurations and tuber microclimate. Based upon results from bed configurations and irrigation treatments tested, potatoes performed best planted in flat beds and irrigated with drip irrigation. Flat beds appear to provide cooler soil temperatures near developing tubers.

Publications

Ayars, J. E., D. A. Bucks, F. R. Lamm, and F.S. Nakayama. 2006. Introduction. Chapter 1 in Microirrigation for Crop Production - Design, Operation and Management. F.R. Lamm, J.E. Ayars, and F.S. Nakayama (Eds.), Elsevier Publications. pp. 1-26. Bordovsky, J.P. and D.O. Porter. 2006. Comparison of Subsurface Drip Irrigation Uniformity Designs on Cotton Production on the Texas South Plains. ASABE Paper # 06-2276. Presented at: 2006 Annual International Meeting of the American Society of Agricultural and Biological Engineers, Portland, OR. July 9-12, 2006 Clark, G. A., F. R. Lamm, and D. H. Rogers. 2005. Sensitivity of thin-walled drip tape emitter discharge to water temperature. Appl. Engr in Agric. 21(5):855-863. Colaizzi, P.D., S.R. Evett, and T.A. Howell. 2006. SDI Bed Design Comparison for Soybean Emergence and Yield. ASABE Paper # 06-2279. Presented at: 2006 Annual International Meeting of the American Society of Agricultural and Biological Engineers, Portland, OR. July 9-12, 2006 Colaizzi, P.D., S.R. Evett, and T.A. Howell. 2006. Subsurface Drip Irrigation (SDI) Research at USDA-ARS in Bushland, TX. Presented at: 2006 International Conference on Water in Arid and Semiarid Lands, 15-17 Nov, Lubbock, TX, Texas Tech University International Center for Arid and Semiarid Land Studies (ICASALS). Colaizzi, P. D., P. H. Gowda, T. H. Marek, and D. O. Porter. 2006. Reducing Ogallala withdrawals by changing cropping and irrigation practices in the Texas High Plains. In Ground Water and Surface Water Under Stress: Competition, Interaction, Solutions (Wichelns, D. and Anderson, S. S., eds.), 25-28 Oct., Boise, ID. U. S. Committee on Irrigation and Drainage, Denver, CO. pp. 113-126. Colaizzi, P. D., F. R Lamm, T. A. Howell, and S. R. Evett. 2006. Crop production comparison under various irrigation systems. In: Proc. Central Plains Irrigation Conference, Colby, KS., Feb. 21-22, 2006. Available from CPIA, 760 N.Thompson, Colby, KS. pp. 189-207. Feibert, E.B.G., C.C. Shock, L.D. Saunders, and L.B. Jensen. 2006. The Effectiveness of Root Feed II and STO-5 for Onion Production When Injected into a Drip-irrigation System. In Oregon State University Agricultural Experiment Station, Special Report 1070:129-133. http://www.cropinfo.net/AnnualReports/2005/RootFeedOnion05.html Jensen, Lynn, L.B., E.B.G. Feibert, C.C. Shock and L.D. Saunders. 2006. A One-year Study on the Effectiveness of Vydate L (Oxamyl) to Control Thrips in Onions When Injected into a Drip-irrigation System. In Oregon State University Agricultural Experiment Station, Special Report 1070:109-115. http://www.cropinfo.net/AnnualReports/2005/EffectOxymyl05.html Lamm, F. R., J. E. Ayars, and F. S. Nakayama (Eds.). 2006 Microirrigation for Crop Production - Design, Operation and Management. Elsevier Publications. 608 pp. Lamm, F.R. and C.R. Camp. 2006. Subsurface drip irrigation. Chapter 13 in Microirrigation for Crop Production - Design, Operation and Management. F.R. Lamm, J.E. Ayars, and F.S. Nakayama (Eds.), Elsevier Publications. pp. 473-551. Lamm, F. R. and T. P. Trooien. 2005. Dripline depth effects on corn production when crop establishment is nonlimiting. Appl. Engr in Agric. 21(5):835-840. Lamm, F. R. and R. M. Aiken. 2005. Effect of irrigation frequency for limited subsurface drip irrigation of corn. In Proc. Irrigation Assn. Intl. Irrigation Technical Conf., November 6-8, 2005, Phoenix, AZ. IA Paper No. IA05-1264. 10 pp. Lamm, F.R. 2006. Progress with SDI research at Kansas State University. In: Proc. Central Plains Irrigation Conference, Colby, KS. Feb. 21-22, 2006. Available from CPIA, 760 N.Thompson, Colby, KS. pp. 67-85. Lamm, F. R., D. M. OBrien, D. H. Rogers, and T. J. Dumler. 2006. Using the K-State center pivot sprinkler and SDI economic comparison spreadsheet. In: Proc. Central Plains Irrigation Conference, Colby, KS., Feb. 21-22, 2006. Available from CPIA, 760 N.Thompson, Colby, KS. pp. 86-93. Lamm, F. R. T. P. Trooien, and A. J. Schlegel. 2006. Applying swine effluent with SDI and LEPA sprinkler irrigation. Proc. 27th Annual Intl. Irrigation Assoc. Tech. Conf., San Antonio, Texas, November 5-7, 2008. Paper No. IA06-1517. Proceedings available on CD-Rom from Irrigation Association, Falls Church, Virginia. Lombard, K, S.C. Forster-Cox, D. Smeal, and M.K.ONeill. 2006. Diabetes on the Navajo nation: what role can gardening and agriculture extension play to reduce it? Journal of Rural and Remote Health. http://rrh.deakin.edu.au/articles/showarticlenew.asp?ArticleID=640 ONeill, M.K., D. Smeal , R.N. A , and K. Lombard. 2006. Growth and survival of drip-irrigated hybrid poplar in the semi-arid Four Corners region. Journal of Sustainable Forestry. 23:47-62. DOI: 10.1300/J091v23n02_03. ONeill, M.K. and M.M. West (eds.) 2006. Thirty-ninth Annual Progress Report: 2005 Cropping Season. With contributions from R.N. Arnold, D. Smeal, R. Heyduck, C.K. Owen, Z. Williams, K.D. Kohler, K. Lombard, N. Pryor, and J. Tomko. NMSU Agricultural Science Center at Farmington. Agricultural Experiment Station and Cooperative Extension Service. New Mexico State University. Las Cruces, NM. http://spectre.nmsu.edu/dept/docs/farm/2005prfarm.pdf ONeill, M.K., K.A. Lombard, B.M. Onken, A.L. Ulery, and M.K. Shukla. 2006. Power plant combustion byproducts for improved crop productivity of agricultural soils. Final Report prepared for the U.S. Department of Energy National Energy Technology Laboratory and the Combustion Byproducts Recycling Consortium. NMSU Agricultural Science Center at Farmington. Agricultural Experiment Station and Cooperative Extension Service. New Mexico State University. Las Cruces, NM. 95 pages. http://wvwri.nrcce.wvu.edu/programs/cbrc/reports/02-CBRC-W9.pdf ONeill, M.K. 2006. Reducing barriers to adoption of microirrigation. W-1128 Annual Meeting. November 1-3, 2006. San Antonio, TX. Secretary for the 2005 meeting and responsible for putting together the 2005 meeting minutes and the 2005 Annual Report. http://nimss.umd.edu/homepages/saes.cfm?trackID=5254#2 ONeill, M.K., R. Heyduck, K. Lombard, D. Smeal, R.N. Arnold, J. Mexal, and B. Onken. 2006. Sustainable poplar production for multiple uses in the Four Corners: applied research. The 7th Biennial Conference of the Short Rotation Woody Crops Production Systems for Wood Production, Bioenergy and Environmental Services. September 25-29, 2006. Pasco, WA. ONeill, M.K., K. Lombard, D. Smeal, R.N. Arnold, R. Heyduck, J. Mexal, and B. Onken. 2006. Poplar-based agroforestry in arid/semi-arid regions: opportunities and challenges in a growing world. June 5-9, 2006. Fourth International Poplar Symposium. International Union of forestry Research Organizations (IUFRO). Nanjing, China. Pereira, A.B., C.C. Shock, E.P. Eldredge, and L.D. Saunders. 2006. Effect of irrigation systems and cultural practices on potato performance. In Oregon State University Agricultural Experiment Station, Special Report 1070:177-186. Pereira, A.B., C.C. Shock, E.B.G. Feibert, R.J. Flock, L.A. Lima, and N. Fernandes. 2006. Monitoramento da irrigação por meio da tensão da água do solo. Editora UEPG, Ponta Grossa, Paraná, Brasil. ISBN: 85-86941-78-6. 20p. Porter, D. and T. Marek. 2006. Irrigation Management with Saline Water. In: Proceedings of the 18th Annual Central Plains Irrigation Conference and Exposition. Colby, Kansas. February 21-22, 2006. Rogers, D. H. and F. R. Lamm. 2006. Criteria for successful adoption of SDI systems. In: Proc. Central Plains Irrigation Conference, Colby, KS., Feb. 21-22, 2006. Available from CPIA, 760 N.Thompson, Colby, KS. pp. 57-66. Rogers, D., F. Lamm, T. Trooien, and M. Alam. 2006. Subsurface drip irrigation (SDI) with livestock wastewater. KSU Cooperative Extension, Manhattan, KS. MF2727. 4 pp. Shock, C.C., R.J. Flock, E.P. Eldredge, A.B. Pereira, and L.B. Jensen. 2006. Drip Irrigation Guide for Potatoes in the Treasure Valley. Oregon State University Extension Service, Corvallis. EM 8912-E. 6p. http://extension.oregonstate.edu/catalog/pdf/em/em8912-e.pdf Shock, C.C. 2006. Drip Irrigation: An Introduction. Oregon State University Extension Service, Corvallis. EM 8782-E (Revised October 2006) 8p. http://extension.oregonstate.edu/catalog/pdf/em/em8782-e.pdf Shock, C., R. Flock, E. Feibert, A. Pereira, and M.K ONeill. 2006. Drip irrigation guide for growers of hybrid poplar. Cooperative Extension Service Pub. EM 8902. Oregon State University. Corvallis, OR. http://extension.oregonstate.edu/catalog/pdf/em/em8902.pdf Shock, C.C., A.B. Pereira, E.B.G. Feibert and R.J. Flock. 2006. Irrigação por goteijamento na produção de alamo; guia prático. Editora UEPG, Ponta Grossa, Parana, Brasil, ISBN: 85-86941-70 16p. Shock, C.C. R. Flock, E.B.G. Feibert, C.A. Shock, A.B. Pereira y L. Jensen. 2006. El control del riego mediante la tensión matricial del suelo. Oregon State University Extension Service, Corvallis. EM 8900-S-E. 8p. http://extension.oregonstate.edu/catalog/pdf/em/em8900-s-e.pdf Shock, C.C., E.B.G. Feibert, L.D. Saunders and J. Klauzer. 2006. Alfalfa seed quality favored by water stress. In Oregon State University Agricultural Experiment Station, Special Report 1070:9-26. http://www.cropinfo.net/AnnualReports/2005/Alfseed3yr.htm Shock, C.C., E.B.G. Feibert, and L.D. Saunders. 2006. Subsurface drip irrigation for native forb seed production. In Oregon State University Agricultural Experiment Station, Special Report 1070:39-41. http://www.cropinfo.net/AnnualReports/2005/ForbsSDI05.html Shock, C.C., E.B.G. Feibert, and L.D. Saunders. 2006. Micro-irrigation alternatives for hybrid poplar production 2005 trial. In Oregon State University Agricultural Experiment Station, Special Report 1070:139-151. http://www.cropinfo.net/AnnualReports/2005/Popirr2005.html Shock, C.C., E.B.G. Feibert, and L.D. Saunders 2006. Water management for drip-irrigated spring wheat. In Oregon State University Agricultural Experiment Station, Special Report 1070:241-247. Http://www.cropinfo.net/AnnualReports Smeal, D., M.K. ONeill, and R.N. Arnold. 2006. Evaluation of a low-cost, low-tech microirrigation system designed for small plots. 27th International Irrigation Association Annual Meeting. Nov. 5-7, 2006. San Antonio, TX. Smeal, D., M.M. West, Z.F. Williams, M.K. ONeill, K. Lombard, and R.N. Arnold. 2006. Efficient irrigation of small plots using a simple, inexpensive micro-irrigation system. Proc. ICASALS 2006 Conference: Water in Arid and Semiarid Lands: Innovative Approaches and Informed Decision-Making. Abstracts pg. 110. November 15-17, 2006. Lubbock, TX. Smeal, D., Z. Williams, M.M. West, M.K. ONeill, and R.N. Arnold. 2006. Drought-tolerant plants for urban landscapes in northern New Mexico. Symposium on Efficient Water Use in the Urban Environment. February 23-24, 2006. Las Cruces, NM. Smeal, D., Z.F. Williams, M. West, M.K. ONeill, and R. Arnold. 2006. Drought-tolerant plants for urban landscapes in northern New Mexico. 11th Xeriscape Conference: Restoring Our Waters: Think Globally, Act Locally. March 9-11, 2006. Albuquerque, NM. Smeal, D., Z.F. Williams, M. West, M.K. ONeill, and R. Arnold. 2006. Drought-tolerant plants for urban landscapes in northern New Mexico. Santa Fe Garden Fair: The Joys and Challenges of Santa Fe Gardening. April 29, 2006. Santa Fe, NM. Taber, H.G. 2005. Vegetable irrigation scheduling. Presented at IA_IL Fruit and Vegetable Symposium, Bettendorf, IA, Dec 1, 2005 Taber, H.G. 2006. Potassium application and leaf sufficiency level for fresh-market tomatoes grown on a Midwestern United States fine-textured soil. HortTechnology 16: 247-252. Taber, H.G. and V. Lawson. 2006. Irrigation scheduling for optimum sweet bell pepper production. Proc. Natl. Agr. Plastics Congr. 33: CD format.

Impact Statements

Florida strawberry growers are currently using BMPs to reduce seasonal nitrate-N losses below 3%.
In IA, crop N efficiency can be improved, compared to the standard grower practice of routinely adding additional N, if the PSNT monitoring tool is employed in making the sidedress N decision.
The Minolta SPAD meter is routinely used to evaluate hybrid poplar clones for levels of chlorosis caused by Fe deficiencies in calcareous soils common to arid and semi-arid regions.
Interest in drip-irrigated hybrid poplar production has lead to a Department of Energy phytoremediation project based on the use of hybrid poplar and other woody perennials for mitigating nitrate-contaminated groundwater originating from a former uranium processing site.
A simple electronic dendrometer connected to a datalogger was used to measure radial tree growth on an hourly basis. Growth rates were identical to those determined with a tape measure on an annual basis.
Using a low-tech drip system at low levels of irrigation (less than 50 cm) drip-irrigated tomatoes exhibited water use efficiencies (yield/water applied) two times that of sprinkler irrigated tomatoes. In chile peppers, water use efficiencies (yield/water applied) of drip-irrigated plots ranged from 1.5 to 2 times those of sprinkler irrigated plots at irrigation levels ranging from 26 to 50 cm, respectively.
Research of xeric landscapes showed that, to maintain acceptable quality a well designed, drip-irrigated xeriscape (average 4-foot plant spacing) used less than 20% of the water required by a cool season grass turf and about 25% that required by a warm season turf.
Observations for onion growers records showed that growers used 115 kg/ha less fertilizer N when irrigated with SDI than with furrow irrigation. Microirrigation has the potential to reduce water use, leaving more water in streams and reservoirs. Surface water contamination of streams can be less with micro irrigation and groundwater contamination by nitrate and pesticides can be sharply lower. The environmental benefits of microirrigation can only be achieved if micro irrigation proves to be economically feasible through reductions in other costs not related to the added costs of the micro irrigation system and improvements in crop yield or quality. Drip-irrigated onion has expanded, with vastly reduced N inputs and no irrigation-induced erosion and associated pollutant runoff. Thirty to 40 percent less water was required using SDI.
Managing irrigation according to crop requirements (evapotranspiration) will increase water use efficiency and is expected to reduce technical and water management barriers associated with micro-irrigation in the U.S. Virgin Islands. Expanding the production season into the dry season for a year-round supply of fruits and vegetables will impact directly on the local economy by reducing imports from the U.S. mainland and Caribbean countries.
In the Texas Southern High Plains, rapid adoption of subsurface drip irrigation primarily for cotton production has been observed in recent years. Research programs in the region have produced engineering recommendations regarding design, maintenance, and management of SDI systems, as well as agronomic recommendations addressing fertility, crop variety selection, and plant population.

Date of Annual Report: 12/20/2007

Report Information

Annual Meeting Dates: 10/09/2007 - 10/11/2007
Period the Report Covers: 10/01/2006 - 09/01/2007

Participants

Daugherty, LeRoy Administrative Advisor (ldaugher@nmsu.edu) - New Mexico State University; ONeill, Mick (Chairman) (moneill@nmsu.edu) - New Mexico State University; Porter, Dana (Vice Chairman) (d-porter@tamu.edu) - Texas A&M University; Fares, Ali (Secretary) (afares@hawaii.edu) - University of Hawaii; Alam, Mahbub (malam@ksu.edu) - Kansas State University; Clark, Gary (gac@ksu.edu) - Kansas State University; Lamm, Freddie (flamm@ksu.edu) - Kansas State University; Neibling, Howard (hneiblin@uidaho.edu) - University of Idaho; Parsons, Lawrence (lrp@crec.ifas.ufl.edu) - University of Florida; Prestwich, Clarence (clarence.prestwich@por.usda.gov) - USDA/NRCS, Portland, OR; Schwankl, Larry (schwankl@uckac.edu) - University of California, Davis; Shackel, Kenneth (kashackel@ucdavis.edu) - University of California, Davis; Shock, Clint (clinton.shock@oregonstate.edu) - Oregon State University; Stanley, Craig (cdstan@ufl.edu) - University of Florida; Vance, George Floyd: GFV@uwyo.edu) - University of Wyoming; Yitayew, Muluneh (myitayew@ag.arizona.edu) - Uiversity of Arizona

Brief Summary of Minutes

Tuesday October 9, 2007 (8:00am to 5:00pm)

The meeting of the W-1128 group started at 8:00 am on Tuesday October 9, 2007 at the Ocean Resort Hotel, Honolulu HI. Dr. Ali Fares (University of Hawaii) presented the schedule for the meeting including for the field visit at Waimanalo Agricultural Experimental Station of the College of Tropical Agriculture and Human Resources, University of Hawaii, for Thursday October 11, 2007. The meeting agenda was presented by the Chairman, Dr. Mick ONeill of New Mexico State University.

Dr. LeRoy Daugherty, the Administrative Advisor, discussed the issues regarding the 3 year review this past summer and the future renewal of the project. Dr. Daugherty talked about concerns for documenting outcomes (especially multi-state outcome) for the project. He mentioned a future water conference in Reno, NV. He informed the participants that NRI announced there RFP two weeks ago; a letter of intent is needed before submitting the full project proposal. Dr. Daugherty discussed the federal budget. The funds which were in earmark accounts with CSREES were moved to the Hatch account. Hatch funds may increase in this years appropriation. The proposed changes in the organization of USDA as proposed by CREATE 21 were discussed. The proposal is accessible at www.create-21.org. He indicated integrated projects are viewed favorably and the Create-21 proposal is supported by Experiment Station leaders.

The Administrative Advisor reminded the participants that it is time to write NRI proposals. Dr. ONeill mentioned that AR and TX were very successful for the South Central Sun Grants Initiative. The theme of the Initiative is cellulosic conversion for liquid fuels. They emphasized that a refinery of the envisaged size would require 1,000,000 dry tons of biofuel per year to produce the projected quantity of liquid fuel. To achieve this production level, a constant daily feedstock supply of 5,500 tons of biomass will be required which must be supplied by approximately 225 trucks each day unloading at a rate of 1 truck every 3 minutes. Dr. Daugherty told the group that bioenergy, bioconversion, and other related topics are of interests to many funding agencies followed by environmental issues.

Discussion on the New Proposal for the W-1128 Group
Objective 1: Survey for Microirrigation (Coordinator Dr. Freddie Lamm)
The group was informed that in Kansas State the team visited some of the producers; they believe that most problems are related to management and misunderstanding of some of the entries in the survey. Overall, they are very satisfied. People have difficulties with the early systems i.e., design and management problems. Dr. Ken Shackel wants a copy of the survey. Dr. Mahboub Alam and Dr. Freddie Lamm told that the survey has been posted online since 2005. It was discussed that there is lots of expansion of sub-surface irrigation in Texas and should the contents of the survey be specific to each state or should be generalized. Dr. Gary Clark suggested documenting how much have been achieved from this survey.

Dr. Dana Porter (Vice Chairman) pointed out that county agents have established some type of survey of their own emphasizing on the education component. She told that as she took to take data from the extension reports and analyze them. She added that the rodents may become a problem because of the use of corn and sorghum. Switching from cotton to corn under flood irrigation impacts the irrigation frequency. It was also mentioned that cotton in TX is increasing but decreasing in CA.

Survey for Water Availability and Water Use
It was told that no one is working on this survey any more in Kansas State. The survey we used to help our growers. It was discussion that to wrap up the 5 year report it is better to use last year report for that. The group was also informed that there is interest on sending the survey to other growers in other states. Dr. Gary Clark suggested that it may be a good idea to interview the county agents instead of the growers. The group was informed that in CA its difficult to get feedback from participants because they are over surveyed and in Kansas State the success rate is 33% which is a very good rate. The disclaimers are very helpful in getting reply/feedback.
Dr. Muluneh Yitayew (Arizona) inquired about the objective behind the survey. Dr. Lamm responded that it is very important to know the barriers. Dr. Daugherty told that ARS is developing an Irrigation Survey and it might be a good idea to contact ARS. The discussion was wrapped up with the information that Dr. Lamm has a webpage to get the information that was submitted. The work should be continued. People might want to do it one time but not periodically. Dr. Mick ONeill suggested that in case any one wants to conduct the survey, he/she should get in touch with Dr. Lamm and Dr. Alam.

Objective 2: (a) System Design and Hydraulics, (b) System Installation and Performance
Dr. Gary Clark emphasized to make drafting committee for next project and the responsible person for next report. Dr. Clark told that he has information and data about system design, water treatment practices and filter performance, and lab tests and complete field studies on clogging. Dr. Larry Schwankl mentioned about a manual on maintenance and clogging he developed and which is going to be printed soon. It was decided that Dr. Schwankl will take a lead with the help of Dr. Lamm and Dr. Porter to compile all the information and data to draft a project on emitter clogging and the effect of stretching the tube on its performance for waste water delivery. This will include a summary page about the findings. The project may be available on a webpage for inputs. The objectives may include solution for iron and calcium clogging and maintenance of the system with emphasis on clogging.

Objective 3: ET and Irrigation Scheduling
Different methods are useful for ET estimation and irrigation scheduling. Dr. Lamm discussed that relative crop yield as a function of relative water use. The average response does not reflect water use variability from year to year. There is a problem with the definition of the term total water use because it includes runoff and excess losses drainage. This may introduce Irrigation Deficit Integral, IDI.

Dr. Kenneth Shackel suggested comparing a crop yield data with Dr. Lamms IDI data. Relative ET, crop coefficient (Kc) and potential ET are also needed. Additionally, a detailed precipitation data is needed to reasonably determine effective rainfall. The data should represent as many years as possible, may be in shape of a spreadsheet. Dr. Shackel will work on it.

New Project
Dr. Clint Shock presented a talk on his microirrigation work on Potato.
The group discussed work on potential new research topics including:
" Water and energy,
" Food security,
" Water scarcity,
" Reclaimed water from urban areas and from industrial,
" Use and dispose of water to drip system.

The proposed project would have sound objectives based on above discussion and proper methodology to adopt.

Dr. Gary Clark suggested emphasizing on plant and system based major categories. The prior will address (a) crop water use and production, and (b) scheduling and management. The later will deal with filtration and treatments control issues. Dr. Muluneh Yitayew suggested working on a) energy efficiency under micro-irrigation and b) micro-irrigation under urban settings. The project has several other suggested topics that could be addressed including:

" Rodent management in SDI
" Clogging management
" Energy use efficiency in MI
" Germination management
" Wastewater use
" Urban water management
" Differential plant response to irrigation system/management
" Overcoming thermal limitations using SDI
" WERA011: Western Regional Turfgrass Research

This ended the Tuesdays activity. The participants were taken to Casablanca, a Moroccan food restaurant, at 19 Hoolai St. Kailua, HI 96734. The dinner was from 7:00 pm to 10:00 pm during which the participants continued informal discussion. Pick and drop service was provided.

Wednesday October 10, 2007 (8:00 am to 5:00 pm)
The group resumed discussion on Wednesday October 10, 2007 at the same location. They continued discussing the title of new research topic for the group. The selected title was Microirrigation for sustainable water use and environmental stewardship was proposed. Several other titles were suggested for further discussion including
" Microirrigation for water conservation and enhanced plant productivity.
" Microirrigation to improve water conservation and plant productivity.

State presentations
Dr. Lawrence Parsons (University of Florida) presented a talk on How to Live with Less Water. Craig Stanley also presented a talk. Dr. Mahboub Alam gave talked about the survey and their help to different stake holders on clogging. Dr. George Floyd Vance and also delivered a presentation. Elvin Roman-Paoli gave Puerto Ricos report. Dr. Dana Porter and Dr. Clarence Prestwich also gave their oral presentations. Dr. Schwankl talked briefly about his new extension book on how to diagnose clogging and find solutions. Dr. Clark talked about preventive measures. The industry welcomes this effort and may support it. Dr. Clark needs a volunteer to help him.

Business meeting:
It was decided to update the website. Currently all the annual reports are on the NIMSS site. Dr. Clint Shock suggested that we need to standardize the reporting e.g., Arial 12 fonts in Word format. Dr. ONeill suggested sending presentations in a pdf format. It was also decided to send a report to Dr. Daugherty within 60 days. The report should approximately comprise 1200 characters including milestones and objectives. The coordinators should send their input to be a part of this report. The deadline to get individual inputs was set to November 9, 2007. Following people will send the material: Gary Clark, Freddie Lamm, Kenneth Shackel, Clint Shock and Craig Stanley.

Next meeting of the group will be held October 22-24, 2008 in Portland, OR.

Accomplishments

Microirrigation Survey (Objective 1. Coordinator: Freddie Lamm) Report from Dana Porter, TAMU: In 2006, estimates by Jim Bordovsky (Texas Agricultural Experiment Station) and Paul Colaizzi (USDA-ARS, Bushland) indicated that there were as many as 100,000 ha of subsurface drip irrigation (SDI) in the Texas High Plains. By far the majority of the SDI irrigation in the region is for cotton irrigation. Other SDI crops include alfalfa, vegetables, corn, wine grapes and other crops. Commercial installation of SDI systems continues to expand microirrigation application in the region. With recent increases in grain and oilseed prices, some SDI irrigated land in predominantly cotton areas (such as the Texas Southern High Plains) is expected to produce corn, sorghum and other crops. This may increase concerns about salinity accumulation in the root zone, rodent damage to tape laterals, and root intrusion into emitters. Factors affecting the high rate of SDI adoption in the Texas High Plains: Paul Colaizzis work addresses the issues well: high and fluctuating fuel costs, limited (and declining) irrigation well capacity, and potential for high yields and WUE. USDA-NRCS EQIP cost-share funds have assisted with purchase of low pressure center pivots (LEPA & LESA) and SDI systems to replace furrow irrigated systems (primarily) and to upgrade from other less efficient irrigation systems. Farm journals (including Southwest Farm Press), and local media (water district newspapers, radio programs, etc.) have kept SDI in the spotlight for several years. Increasing numbers of experienced dealers, designers, installers, etc. in the area continue to build the equipment and expertise "infrastructure" and contribute to the high level of marketing. Further south and west (Pecos and Garden City, TX areas), very low well capacities make SDI an option where there is just not enough water to run center pivots. SDI works in soils and topographies where furrow irrigation does not work as well. SDI is also a good fit in fields that are small or are otherwise not well suited to center pivots. Limitations: Initial cost is a big issue. Problems with crop germination and rodent damage are real issues in some areas. Jim Bordovskys work has done a lot to address some of the water quality induced maintenance issues (manganese problem.) Extension and research personnel regularly receive inquiries regarding water quality suitability for SDI and for information about acid injection and other maintenance requirements. Support for County Extension Faculty: Program planning efforts with Extension agents in the Texas High Plains (Panhandle and South Plains) and Rolling Plains regions indicate that there is local demand for educational events that address microirrigation related topics, including management, maintenance, and trouble-shooting. In response to these needs, the topics were included in a regionally standardized strategic plan that includes program evaluation instruments and information resources lists. Dana Porter coordinated these tasks with a team of twelve Extension agents and specialists. Report from Mike Bartolo, CSU A questionnaire was sent out to 173 growers in the Patterson Hollow area in late February of 2005 with 20 questions pertaining to drip irrigation. Patterson Hollow is located in the Arkansas River Valley of SE Colorado near the town of Rocky Ford. Forty-six (46) survey questionnaires were returned. Of those reporting, 4 respondents were presently using drip irrigation, 17 were interested in learning more about drip irrigation and felt it would benefit their operations, 2 were interested in only learning more about drip irrigation and 27 indicated they had no interest in drip irrigation or it didn't fit their farming operations. It should be noted that along with our survey, the Lower Arkansas Valley Water Conservancy District has sponsored 6 or more workshops in the area over the past two years. The workshops explain the various facets of drip irrigation. Objective 2. System Design and Hydraulics To reduce technical barriers associated with microirrigation system design, performance, and maintenance (Annual Report Gary Clark, Kansas State University) Microirrigation with livestock wastewater. An engineering feasibility emitter discharge study showed that the drip irrigation laterals used with SDI have potential for use with beef lagoon effluent. However, the smaller emitter sizes normally used with groundwater sources to maximize zone size and length of run may be risky for use with lagoon effluent. Emitter discharge in the range of 1.5 to 2.3 L/hr-emitter performed well over the course of four seasons and resulted in little clogging. The results from a swine effluent agronomic study indicate that SDI can result in better corn production with less water, less nitrogen volatilization and less leaching than LEPA sprinkler irrigation. Results from using livestock lagoon water (beef, dairy, and swine) through high flow drip emitters (11 L/hr at 105 kPa) showed no measurable change in flow rate. The emitters were periodically flushed with freshwater. A hydraulic performance and maintenance field test with four heavy walls, polyethylene pipe drip tubing products and livestock lagoon wastewater was conducted. Drip tube laterals included two pressure compensating emitters and two non-compensating emitters. All emitters had nominal flow rates of about 3.5 L/hr. One of the compensating emitter laterals and one of the non-compensating emitter laterals were marketed for use with wastewater while the alternative products were for normal irrigation water use. The tubes were installed as 24.4 m long laterals on 1.2 m centers, and were 0.60-m deep. The system was operated through the 2004 and 2005 summer seasons. Tubing flow rates were monitored with flow meters on individual laterals with minimal flow rate changes within any of the different tubes. Treatment with acidified water (pH=2) cleared up most clogging. Two studies evaluated the use of livestock lagoon wastewater (beef, dairy, and swine) with drip irrigation of poplar trees. In a lysimeter study, trees were grown on a sandy soil that had very little nutrient content prior to the study. Irrigation with livestock lagoon wastewater resulted in significant growth increases (height and trunk diameter) over irrigation with only freshwater. Leaf mass, woody mass, and root mass were all significantly greater from the lagoon irrigation treatments. In a field study poplar trees were grown on a silty clay loam soil that was previously used for application of livestock wastes and had substantial levels of soil N and P. In the field study, poplar trees that were irrigated with only fresh water resulted in larger trunk diameters than trees that were irrigated with livestock lagoon water. However, tree height and crown area were not different. The amount of soil nitrate-N was also significantly greater for the lagoon irrigated trees. Lab hydraulic studies on microirrigation products. Lab studies were initiated to evaluate the hydraulic performance of emitters from collapsible drip tubing after stretching. A stretching apparatus was designed and constructed to stretch short sections (2-m) of collapsible drip irrigation tubing. Initial studies stretched tubing samples by 10% for 1 hour. Hydraulic performance of drip emitters was measured before and after stretching at operating pressures of 55, 69, and 83 kPa. Preliminary data indicate that one type of drip tubing has resulted in increased emitter flowrates ranging from 3 to 5 percent as a result of stretching. A second drip tubing type had minimal change in emitter discharge at the 55 and 69 kPa settings and a 1 to 2 percent increase in flow at the 83 kPa pressure setting. Additional lab tests are to be repeated and continued with other tubing samples. Draft handbook of maintenance of microirrigation systems A draft version of a handbook has been developed by L. Schwankl, B. Hanson and T. Prichard. The current draft is in review. " ET and Irrigation Scheduling (Objective 3) " Nutrient Dynamics (Objective 3) " Micro-Environmental Effects (Objective 3) Objective 3: SDI Installation issues Progress Report: The present disk bedding implement used by KSU-NWREC sometimes results in non-uniform seedbeds in terms of soil water, residue and firmness. In the summer of 2006, an effort was made to add a rolling cage firmer to the existing disk bedder. A study area was established to evaluate three bedding technologies (Conventional, Beds firmed by Rolling Cage, Beds shaved in spring) under three different levels of spring preseason subsurface drip irrigation (75, 150 or 225 mm). This study was to be conducted during the 2007 summer planting season but was postponed due to wet spring conditions negating germination issues. It is on schedule for 2008. Corn production is being examined under four emitter spacings of 0.3, 0.6, 0.9 or 1.2 m with concurrent soil water measurements. Results from 2006 and observations to date in 2007 indicate that there are no differences in corn yields for these emitter spacings. These data along with earlier data suggest that there is increased soil water movement along the dripline as compared to perpendicular movement away from the dripline. Emitter discharges of 0.68, 0.91 and 1.36 L/h at a depth of 32 mm were compared for near surface soil water redistribution suitable for germination. The results varied with antecedent soil water and compaction conditions but suggest that changing emitter flow rates is unlikely to be very effective in improving germination on this soil type in the range of practical emitter flowrates. The results are still being analyzed. Two papers have been written and presented during the current year concerning wastewater application with a SDI. A paper describing the agronomic aspects of two years of research comparing SDI and LEPA sprinkler application of swine effluent for corn production was presented at the Irrigation Association Technical Conference, San Antonio, Texas, November 5-7, 2006. A second summary paper of both earlier engineering and agronomic research is being presented at the International Symposium on Air Quality and Waste Management for Agriculture, Broomfield, Colorado, Sept. 15-19, 2007. Important conclusions The results from the engineering feasibility emitter discharge study show that the drip irrigation laterals used with SDI have potential for use with beef lagoon effluent. However, the smaller emitter sizes normally used with groundwater sources to maximize zone size and length of run may be risky for use with lagoon effluent. Emitter discharge in the range of 1.5 to 2.3 L/hr-emitter performed well over the course of four seasons and resulted in little clogging. The results from the swine effluent agronomic study indicate that SDI can result in better corn production with less water, less nitrogen volatilization and less leaching than LEPA sprinkler irrigation. Additionally, the summary paper provides a detailed discussion of design and operational guidelines useful when planning application of wastewater through SDI systems. Objective 3: ET and Irrigation Scheduling Multi-year, multi-location comparison of soil-, plant and ET-based irrigation scheduling procedures for microirrigation The 2007 milestone was to develop preliminary descriptions/guidelines for use of various irrigation scheduling procedures and identification of specific conditions where certain methods are inadequate. However, a thorough statistical analysis of the data (part of the 2006 milestone) was a pre-requisite for this milestone, and this analysis has been more difficult to accomplish than anticipated. Accomplishments: ET, applied water and crop yield data from CA, IA, KS, NM, OR and TX was compiled into a standardized format and analyzed using two independent statistical approaches. Both approaches (ANCOVA and smoothed splines) demonstrated a trend in the data of improved maintenance of yield with less applied water for plant-based irrigation scheduling methods compared to soil-based methods, with ET-based methods intermediate. Impacts: If these results are confirmed with additional data and with experiments that are designed specifically to compare the different methods, then the initial impact will probably be a re-evaluation of the widely-held assumption that irrigation management must be based on Evapotranspiration (ET). As part of this re-evaluation, alternative irrigation management approaches such as regulated deficit irrigation (RDI) may lead to substantial water savings. Objective 3: Nutrient Dynamics Protecting Water Quality Through the Use of Effective Water and Nutrient Management Practices for Strawberry Production (Ali Fares, University of Hawaii, Clint Shock, Oregon State University, and Craig Stanley, University of Florida) A project to evaluate the effectiveness of water and nutrient management practices for drip-irrigated strawberry production under a range of soil type and individual grower management levels finished it third year. Water and nutrients leached below the root zone was collected weekly using passive wick collectors installed on 11 commercial strawberry growers fields for the entire growing season. Estimates of seasonal NO3-N losses were determined from quantity and concentration of the weekly collected samples (8 replications per site). Results were very consistent with the two previous years in that overall, there was little seasonal variability of nitrate-N leached from each site at each farm. Individual farm irrigation and nutrient management likely influenced the overall leached N compared to other farms, but soil type may have influence leaching for those farms where similar management intensity occurred regardless of soil type. It would be assumed that the same conclusion could be drawn for other growers using similar management practices. Impact of the results The results have demonstrated to strawberry producers the benefits of using effective BMPs for strawberry production and have been very instrumental for increasing the number of strawberry producers signing up for a State of Florida voluntary BMP adoption program which gives growers a presumed compliance status with regard to future legal actions against them for surface and groundwater contamination issues as long as they use documented BMPs Effect of livestock manure amendment types and levels on nitrate availability and leaching under micro-irrigated sweet corn Two experiments were conducted in Waimanalo and Poamoho research stations of the College of Tropical Agriculture and Human Resources, the University of Hawaii-Manoa. The objective was to study the effect of livestock manure amendment types (Chicken, dairy, and Synthetic fertilizer), rates (0, 150, 300, and 600 lbs/acre total N equivalent) and level (One and two time applications) on nitrate availability and leaching under sweet corn crop irrigated with drip irrigation system and grown on leeward and windward sides of the Island of Oahu, HI. Experimental design was Randomized Complete Block Design with three replications. The experiment included 24 plots, (6 x 60 ft each). Soil solution suction cup lysimeters were installed at 30 and 60cm depths to monitor NO3-N movement within and below root zone, respectively. The results showed a significant difference of manure amendment types, rates and levels of NO3-N concentration within and below root zone. The concentration of NO3-N varied throughout the growing season. The reason was likely the mineralization of manure amendment treatments, spatially and temporally variable rainfall events, and plant growth stages. The crop yield was as expected and sufficient nutrients were available to the plants throughout the growing season. This was because of use of micro-irrigation system which supplies irrigation to the crops as and when needed. Iron chlorosis on micro-irrigated poplar Micro-irrigated poplar tends to develop what appears to be iron chlorosis on alkaline soils. Foliar application of iron products, water run iron chelate, and broadcast applications of sulfur have failed to correct the chlorosis. Concentrated placement of iron products is being tested to overcome this problem.

Publications

Christianson, L.E. 2007. Poplar Phytoremediation Plantation Management. MS Thesis, Kansas State University. Christianson, Laura, Stacy Hutchinson, Gary Clark, and Charles Barden. 2007. Management Implications for a Poplar Phytoremediation Plantation. Oral Presentation. ASABE Annual Intl Meeting. Minneapolis, MN. ASABE Paper No. 077098. Lamm, F. R. T. P. Trooien, and A. J. Schlegel. 2006. Applying swine effluent with SDI and LEPA sprinkler irrigation. Proc. 27th Annual Int´l. Irrigation Assoc. Tech. Conf., San Antonio, Texas, November 5-7, 2008. Available from Irrigation Association, Falls Church, VA. Paper No. IA06-1517. pp. 513-526. Lamm, F. R. T. P. Trooien, and A. J. Schlegel. 2006. Applying swine effluent with SDI and LEPA sprinkler irrigation. Proc. 27th Annual Intl. Irrigation Assoc. Tech. Conf., San Antonio, Texas, November 5-7, 2008. Available from Irrigation Association, Falls Church, VA. Paper No. IA06-1517. pp. 513-526. Lamm, F. R. T. P. Trooien, and A. J. Schlegel. 2007. Application and Utilization of livestock effluent through SDI systems. International Symposium on Air Quality and Waste Management for Agriculture, Broomfield, Colorado, Sept. 15-19, 2007. ASABE, St. Joseph Michigan. CD-Rom. Lombard, K, S.C. Forster-Cox, D. Smeal, and M.K.ONeill. 2006. Diabetes on the Navajo nation: what role can gardening and agriculture extension play to reduce it? Journal of Rural and Remote Health. http://rrh.deakin.edu.au/articles/showarticlenew.asp?ArticleID=640 ONeill, M.K. and M.M. West (eds.) 2007. Fortieth Annual Progress Report: 2006 Cropping Season. With contributions from R.N. Arnold, D. Smeal, R. Heyduck, C.K. Owen, Z. Williams, K.D. Kohler, and K. Lombard. NMSU Agricultural Science Center at Farmington. Agricultural Experiment Station and Cooperative Extension Service. New Mexico State University. Las Cruces, NM. http://cahe.nmsu.edu/aes/farm/documents/nmsu-annrpt-2006-full.pdf Pablo, R.G., M.K. ONeill, B.D. McCaslin, M. D. Remmeng, J. Keenan. 2007. Evaluation of corn grain yield and water use efficiency using subsurface drip irrigation. Journal of Sustainable Agriculture. 30(1). 153-172. DOI: 10.1300/J064v30n01_10. Roberts, M.L. 2006. Evaluation of poplar trees with livestock lagoon wastewater. MS Thesis. Kansas State University. Román-Paoli, E., D. Sotomayor-Ramírez. 2006. New Fertigation Recommendations for Cassava on Non-Traditional Production System. Proc. 42 Annual Meeting. Caribbean Food Crop Society. P.437-442.

Impact Statements

Results from swine effluent agronomic study indicate that SDI can result in better corn production with less water, less nitrogen volatilization and less leaching than LEPA sprinkler irrigation.
Initial impact of the ET work will probably be a re-evaluation of the widely-held assumption that irrigation management must be based on Evapotranspiration (ET). As part of this re-evaluation, alternative irrigation management approaches such as regulated deficit irrigation (RDI) may lead to substantial water savings.
In the Texas Southern High Plains, rapid adoption of subsurface drip irrigation primarily for cotton production has been observed in recent years. Research programs in the region have produced engineering recommendations regarding design, maintenance, and management of SDI systems, as well as agronomic recommendations addressing fertility, crop variety selection, and plant population.
Results under strawberry production demonstrated the benefits of using effective BMPs for strawberry production and have been very instrumental for increasing the number of strawberry producers signing up for a State of Florida voluntary BMP adoption program which gives growers a presumed compliance status with regard to future legal actions against them for surface and groundwater contamination issues as long as they use documented BMPs.
The Navajo Agricultural Products Industry (NAPI) doubled their hybrid poplar acreage by planting an additional 100 acres.
Drip-irrigated hybrid poplar production continued to draw interest resulting in a collaborative ethanol feedstock trial with Washington State University and GreenWood Resources (sponsored by Western Sun Grants) and a DOE-funded phytoremediation with Stoller Corp.
Sizable water savings are achieved by switching from turf-based landscapes to drip-irrigated xeriscapes.

Date of Annual Report: 11/01/2008

Report Information

Annual Meeting Dates: 10/22/2008 - 10/24/2008
Period the Report Covers: 10/01/2007 - 09/01/2008

Participants

Daugherty, LeRoy Administrative Advisor (ldaugher@nmsu.edu) - New Mexico State University; Porter, Dana (Chairman) (d-porter@tamu.edu) - Texas A&M University; Fares, Ali (Vice Chairman) (afares@hawaii.edu) - University of Hawaii; Román-Paoli, Elvin (Secretary) (eroman@uprm.edu) - University of Puerto Rico; Kaleita, Amy (kaleita@iastate.edu)- Iowa State University; Lamm, Freddie (flamm@ksu.edu) - Kansas State University; Neibling, Howard (hneiblin@uidaho.edu) - University of Idaho; O'Neill, Mick (moneill@nmsu.edu) - New Mexico State University; Parsons, Larry (lrp@crec.ifas.ufl.edu) - University of Florida; Prestwich, Clarence (clarence.prestwich@por.usda.gov) - USDA/NRCS, Portland, OR; Rein, Bradley (brein@csrees.usda.gov) CSREES Representative - USDA-CSREES; Schwankl, Larry (schwankl@uckac.edu) - University of California, Davis; Shackel, Kenneth (kashackel@ucdavis.edu) - University of California, Davis; Shukla, Manoj (shuklamk@nmsu.edu) - New Mexico State University; Shock, Clinton (clinton.shock@oregonstate.edu) - Oregon State University; Stanley, Craig (cdstan@ufl.edu) - University of Florida;

Brief Summary of Minutes

Wednesday October 22, 2008

The meeting of the W-1128 group started at 8:00 am at the facilities of NRCS at Portland, Oregon. Dr. Dana Porter presided the meeting. All the participants presented themselves. Dr. LeRoy Daugherty, Administrative Advisor of the W-1128 group, provided copies of several documents which included copies of the current project, last years activities accomplished report, peer review guideline for proposal of new projects, template of the termination report, and project proposal sections. Dr. Bradley Rein made a presentation of some of the changes in the current Farm Bill approved by Congress. He mentioned that the bill includes 6 research divisions which are: 1) Renewable energy, natural resources and environment, 2) Food safety, nutrition and health, 3) Plant health, and production of plant products, 4) Animal health and production of animal products, 5) Agricultural systems and technology, and 6) Agricultural Economics and rural communities. The current W-1128 project falls in division number 5. The current CSREES office will be restructured and become part of the National Institute of Food and Agriculture (NIFA) and will be established on October 1, 2009. He mentioned that there will be mandatory funding for research in the following areas: 1) Specialty crops research initiative, 2) Organic research, and 3) Beginning farmers & rancher program. Of the three mandatory funding areas only specialty crops requires 1:1 matching funds. The website that includes all the information on changes in the Farm Bill is www.csrees.usda.gov. One of the issues that Dr. Rein mentioned is the probability that less funds will be assigned for research than for extension. All proposals must be submitted through website grants.gov and the old program PureEdge will no longer will be used and will be changed for ADOBE. Dr. Rein finished his presentation. Then the members of the nomination committee for the new secretary of the group were selected. The committee was constituted by Dr. Mick ONeill, Dr. Kenneth Shackel, and Dr. Freddie Lamm.

The group initiated the discussion on 2008 milestone. Dr. Lamm indicated that Dr. Mahbub Alam analyzed the results of the survey conducted at Kansas. KS and CO are the only states that participated in the survey. Dr. Larry Schwankl indicated that he completed the ongoing efforts on iron clogging. Doctor Lamm mentioned that he thinks that Dr. Gary Clark will no longer be part of the committee because he is in administrative functions. Dr. Howard Neibling and Dr. Clint Shock agreed to work on drip tape placement. Larry Schwankl mentioned that he decided to change the redaction of a hand book of maintenance of microirrigation systems for a website. Dr. Shackel discussed a milestone regarding evapotranspiration (ET). He found a huge variation in actual water applied among experiments when comparing microirrigation scheduling by using plant or soil-based methods and calculated ETc. There was a discussion among participants about the conformability of crop coefficients.

Dr. Ali Fares suggested that the group should create guidelines to work with microirrigation because of the variation observed among ET and actual AT applied by microirrigation. Larry Schwankl suggested that the new project should work on the comparison of subsurface drip irrigation (SDI) and ET function, yield reduction and variation. Dr. Craig Stanley mentioned that pesticide application effectiveness should be also included in the next project. He mentioned that the replacement for methyl bromide may be applied by the microirrigation system.

Dr. Lamm mentioned that the group must decide if the objectives of the next project should be written broadly, to facilitate the inclusion of everybodys research work, or be narrow just to include the research of persons participating actively in the W-1128. The group decided to write the objectives as narrowly as possible. If someone wants to join the group they should work within those objectives. Dr. Schwankl suggested that research effort should be stated by state groups in a specific topic. Dr. Lamm indicated that he needs help on literature review for the project in research topics he is not familiar with. He also mentioned the possibility of the addition of an economist to the W-1128. Dr. Clarence Prestwich mentioned that one of his colleagues may be interested in joining the group. There was a discussion about design and management of microirrigation systems. Dr. Schakel thinks that management limits design. Dr. Stanley pointed out that residential microirrigation is becoming important (landscaping microirrigation, use of gray water, etc.) Dr. Stanley and Dr. Howard Neibling agreed to work on that topic.

The group discussed the effectiveness of soil moisture sensors. Dr. Neibling proposed to put together an extension publication on soil moisture sensor selection, installation and use. Someone indicated that the group may work on a website dealing with pros and cons of soil moisture sensors available on the market including a section on management for specific crops.

Dr. Schakel indicated that he and other researchers got funded in a specialty crop proposal in which are using surface energy balances. They proposed to create a website showing N and water stressed fields (geo-spatial site specific.) Dr. Schakel and Dr. Manoj K. Shukla agreed to work on developing that kind of technology in the W-1128 group with the help of Ted Sammis. Dana Porter mentioned that an outcome of the project could be developing a workshop with producers, providers and crop consultants in that kind of technology. She mentioned that a product that fits the geo-spatial site specific research is the work that Dr. ONeill and Dr. Shock are working on. This is ET based microirrigation scheduling of poplar on upper and lower ends of the mountains.

Water requirement determination research topics were discussed. The important issue is how to express water requirement (allocation, and water application by irrigation system) on melon, cotton, poplar, landscape plants, biofuel, oil seed crops and forage seed crops. Dr. Schakel insisted that the water requirement is given by the Kc values. If the reference ET is known then crop coefficients can be used. Ali mentioned that crop coefficients are site specific. Dr. Schakel said that the whole concept of crop coefficient is questioned.

Design, management and maintenance issues were discussed. Dr. Schwankl said that not much can be done with clogging. He suggested creating a maintenance website (extension efforts on acid injection, chlorination, filtration, etc.). The issue of deficit irrigation was brought up by Dr. Lamm. There is a difference between deficit irrigation and regulated deficit irrigation (RDI). Water application in RDI is reduced for a period of time to increase or maintain yield and profit or reduce water use.

The group is not clear if the topic regarding maintaining adequate water quality should be eliminated. The group decided to work just in extension activities in urban microirrigation.

Nutrient management, soil additives and pesticides applications fertigation application (protecting water quality, optimizing, nutrient management in production, etc.)

Microirrigation with non-potable water - food safety, security related concern, use of gray water (house waste water, shower, laundry), reclaimed waste water. Waste water management is a multistate type of project because it is expensive to work with. Pathogen transport.

October 23, 2008

The nomination committee selected Dr. Amy L Kaleita from Iowa State University as the new secretary of the group and the following year it will be Dr. Manoj K. Shukla from New Mexico State University.

The next year meeting must be after October 1, 2009 because there cannot be two meetings in the same fiscal year. Dr. Lamm mentioned that in 2010 the meeting could be together with the Irrigation Association meeting. The group decided that next years meeting will be in Puerto Rico from 16-18 November 2009 and Dr. Román Paoli will be in charge of all local arrangements. Dr. Schakel, Dr. Neibling and Dr. Lawrence Parson will be working in the maintenance website. Dr. Daugherty mentioned that the Director of the Agricultural Experiment Station must add researchers through Appendix E.

Dr. Shackel began with the state reports. In synthesis he mentioned that applied water to almonds saves about 5 inches from 40 inches compared with ETc. He pointed out that the group agrees that ET will be expressed as unit area instead of wetted or irrigated area. Tall grass reference crop coefficients are about the same than short grass reference crop coefficients.
The group left for the field trip about 10:00 am.

October 24, 2008

Dr. Shackel continued with state reports. He presented a plot with the relationship between seasonal water requirements of several crops in various environments such as soybean and corn and actual water applied. In soybean, actual water applied was less than 0.3 fraction of ET whereas in corn it was 0.7. To estimate the relationship between ETc and ET0 some assumptions have to be made such as 100% ET and 100% yield and that crop the is not affected by diseases and other yield reducing factors beside water status. Dr. Lamm and Dr. Porter submitted a proposal for SDI education in Texas and Kansas dealing with the protection of the Ogallala aquifer. Dr. Porter mentioned that Kansas has better extension materials than Texas A&M does. The activities of the joint project include field days and revision of extension publications, among other extension activities.

The next state report was given by Dr. Schwankl . He provided as a hand out to the participants a publication titled California microirrigation pocket guide. He also provided some copies of a maintenance handbook, and mentioned the website from which the publication can be downloaded is http://anreatalog.ucdavis.edu (search for publication number 21637). The idea of writing joint publications among states brings up the idea of creating a wiki site for the w-1128 project. Dr. Rein said that a wiki site such as Wikipedia is not considered a scientific site. The advantage of a wiki site is that a group of people can work on a document on the internet without the difficulty of sending documents back and forth. Dr. Parson from UFL presented his research dealing with the testing the Australian sensor SENTELPROBE and ECHO probe EC-5 soil sensor for scheduling irrigation on strawberries. Dr. Ali Fares presented software developed by the water management district of Hawaii to confer water use permits by the state of Hawaii (regulatory software). He explained all the inputs and outputs of the model. Dr. Craig Stanley mentioned that he is working mostly in water management for urban landscapes (looking at run off in turf and landscapes). He is working in alternative sewage treatments such as a treatment to take out the N and return it to the septic tank. Then Dr. Neibling from Idaho informed about his research comparing drip irrigation to sprinkler irrigation on canola. Drip treatment performed better than sprinkler irrigation. He also mentioned that turf grown over buried irrigation systems in a 4 year study showed no intrusion of roots into the drip tape. He mentioned that he is working on a project testing computer based scheduling programs under Idaho conditions. Dr. Shukla says that a more accurate method for measuring soil moisture is gravimetric than the neutron probe. The discussion was stopped for lunch. The discussion resumed at 1:30 pm with Dr. Lamm commenting about a short meeting with coordinators before lunch. They agreed that if researchers send a title and objectives that do not fit the current proposed objectives, then it will be returned to the researcher to find a research topic that fits, unless something comes up that may be of multistate interest, then a new objective could be created. Dr. Mick ONeill talked about his ongoing research on irrigation scheduling in hybrid poplar trees. He tested 70, 80, 120, and 130% ETc on four poplar clones. The next state report was given by Dr. Shukla from NM, who talked about field and laboratory calibration with CS640. He calibrated the sensor to fit the field data. Dr. Shock talked about comparison of irrigation of onion by microsprinkler and drip irrigation. Water applied is way over ETc. Dana Porter talked about her extension work in Texas with other colleagues. The meeting adjourned about 5:00 pm.

Accomplishments

Objective 1. To identify and assess the significance of barriers to adoption of microirrigation. No more to accomplish in this objective. Objective 2. To reduce technical barriers associated with microirrigation system design, performance, and maintenance. The relative response of cotton to subsurface drip irrigation (SDI), low-energy precision application (LEPA), and spray irrigation varied with irrigation rate (25%, 50%, 75%, and 100% of full crop evapotranspiration) and inter-annual climatic variability (2003, 2004, and 2006, and 2007 seasons). For deficit irrigation (2-5 and 50% irrigation rates), SDI generally resulted in greater cotton seed yield, lint yield, water use efficiency, and gross returns; however, differences in response parameters were not always significant. Loan value (as reflected by fiber quality) was greatest for SDI for most irrigation rates in 2003 and 2004, but greatest for LEPA for all irrigation rates in 2006. SDI resulted in greater near-surface soil temperatures by 95 days after planting (2006 only), which is a critical consideration for cotton production in thermally-limited climates such as the Northern Texas High Plains and Southwestern Kansas. In 2007, only seasonal water use and seed yield were available due to a significant gin backlog. Unlike previous years, SDI used significantly less water at 25% and 50% irrigation rates; however, seed yield was not significantly different among methods at 25%. At 50%, LEPA resulted in the largest seed yield, whereas SDI resulted in the largest seed yield at 75 and 100%. Corn emergence and final grain yield were evaluated for different subsurface drip irrigation (SDI) bed geometries and lateral depths. Bed geometries consisted of laterals installed in every bed, laterals installed in alternate furrows, and laterals installed in wide beds with twin planted rows (same lateral spacing as alternate furrows). For each bed design, lateral burial depth was 15, 23, and 30 cm, and irrigation rates were 0%, 33%, 66%, and 100% of full crop evapotranspiration (ETc). No significant differences in crop emergence were observed for bed design within a given irrigation rate. Most grain yield variability was related to irrigation rate; however, grain yield was significantly greater with increasing lateral depth (but not bed design) for the 33% irrigation rate. This was likely due to greater evaporation of soil water for shallower lateral depths, which limited final grain yield at the very low (33%) irrigation rate. This experiment will be repeated for corn in the 2008 season and cotton thereafter. Corn yield has not been negatively affected by various emitter spacing of 0.3, 0.6, 0.9 or 0.4 m on a deep well-drained soil in a semi-arid, summer pattern rainfall climate in Kansas. There is some soil water redistribution occurring along the subsurface dripline that helps to mitigate application differences caused by the different emitter spacing. Sunflower, grain sorghum, and soybean yield have not been significantly affected by subsurface dripline depth (0.2, 0.3, 0.4, 0.5 and 0.6 m) in studies where crop germination and establishment were not a factor. Another accomplishments for KS was the development of a software to compare the economics of conversion to center pivot sprinkler irrigation or subsurface drip irrigation from furrow irrigation for corn production was updated and released to the public, February, 2008 http://www.oznet.ksu.edu/sdi/Software/CP_SDI08.xls. Also a software to determine optimum planned corn area and plant population for SDI was updated and released to the public, February, 2008 http://www.oznet.ksu.edu/sdi/Software/COpt_SDI08.xls Potato is conventionally planted in hills. Drip-irrigated potato planted in hills was compared with drip-irrigated potato planted in flat beds with one drip tape per row of plants at 6 cm depth. Potato grown in beds was more productive and tubers had more uniform shape. Additional work focused on drip tape placement and potato row configurations on flat beds. Deep placement of drip tape has been shown to reduce tuber yield and quality compared to shallow placement. Drip tape placement at 6 cm depth was varied horizontally on flat beds 1.8 m wide: two tapes were placed directly in line with each of two plant rows, two tapes were placed 18 cm along side of each two row towards the middle of the bed, or two tapes were placed between each of two double rows of potato. Plots of potato were irrigated independently when the soil water potential between the plants reached -30 kPa. The horizontal tape placement options did not affect tuber yield, grade, or marketable quality. In commercial fields, drip tape placed directly in the crop row was subject to pinching by developing tubers. Pinching of the tape resulted in lost yield in the rows beyond where the tape was pinched. Under drip, the water required to maintain soil water potential was less than 70 % of estimated potato crop evapotranspiration. Objective 3. To reduce existing water and nutrient management barriers associated with microirrigation. Corn was grown with subsurface drip irrigation to determine the effect of pre-anthesis water stress. The results from KS indicate that corn has great ability to tolerate pre-anthesis water stress provided the water deficits can be quickly relieved through irrigation near anthesis. Advanced irrigation scheduling technology using Temperature-Time Threshold or BIOTIC method of irrigation scheduling can be used to effectively irrigate corn in the U.S. Central Great Plains. A TTT of 2.5 hours appeared to correspond reasonably well to a 100% ETc replacement treatment for both grain yield and irrigation amount. Similarly, a 5.5 hour TTT treatment corresponded reasonably well to a 65% ETc replacement treatment. In CA, the fifth and last year of an almond plant-based RDI study showed that almond yields could be fully maintained despite reductions in applied water. These reductions were about 10% below the most conservative estimates of crop ET, and were accomplished on shallow soils with poor water holding capacity. The pooling of data from multiple states, crops and years also showed that surprisingly low amounts of applied water (40 - 50% of tall or short reference ET, respectively) corresponded to levels that were adequate to achieve full crop yield. A group of W-1128 members from CA, NM and TX were successful in obtaining a $4.7M SCRI grant for "Advanced sensing and management technologies to optimize resource management in specialty crops: case studies of water and nitrogen management in deciduous crops under normal and resource-limited conditions. Research conducted in PR during the last two years indicate that avocados trees responded better to a high soil water depletion level (HSWD=40-45 kPa) than a low soil water depletion level (LSWD=10-15 kPa) or rainfed conditions. Trees submitted to HSWD produced the highest canopy volume, fruit number and weight per tree. Microirrigation is needed to achieve acceptable yield if compared with trees growing on rainfed conditions even though is a fairly wet region. Several years of research on an Oxysol in northern Puerto Rico indicated citrus trees (CV Rhode Red Valencia) was not affected by microirrigation. Another factor is limiting orange productivity and growth resulting in low yield. Therefore, another citrus orchard (CV. Rhode Red Valencia grafted on Swingle and Sunki-Benecke rootstock) was established in 2007 in a major citrus production area in which tensiometers are used to schedule microirrigation. The hybrid poplar, OP-367 continued to demonstrate superior yields in both high density (1,740 trees/ac) and low density (435 trees/ac). After 5 growing seasons, this clone produced 93 tons/ac (19 tons/ac/yr) in the high density trial planted in 2003 and after 6 seasons it produced 87 tons/acre (15 tons/ac/yr) in the low density trial planted in 2002. It was also the highest yielding clone (54 tons/ac, 18 tons/ac/yr) after 3 growing seasons in a DOE-supported trial planted at a density of 1,210 trees/ac. A 6-ac poplar trial with 4 outstanding P. deltoides x P. nigra clones, including OP-367, from the DOE trial and 4 water application treatments was planted during April 2007. Preliminary yield data taken during October 2008 while leaves were still on the trees indicate good growth for these D x N clones. Although OP-367 was not the largest entry, it still yielded more than in previously planted trials. The 1.5-acre drip-irrigated vineyard planted in 2007 was rearranged during 2008. Along with the variety trial that includes 14 table and 20 wine grape varieties, and a rootstock trial was installed in 2008 with 2 varieties grafted onto 9 different rootstock. Interest continues with the low-tech, low-cost drip-irrigated vegetable garden and the xeric landscape demonstration for small-scale gardeners and home owners. About 3,540 pounds of marketable produce were harvested from the drip-irrigated (0.14 acre) garden in 2007. This total included 1,559 lbs (49 lugs or 29 bushels) of tomatoes, 391 pounds (55 dozen ears) of sweet corn, and 1,591 pounds (40 sacks) of chili peppers. As in previous years, most plants in the xeric garden survived at all irrigation levels (including rain-fed only) and most exhibited acceptable quality at either the low (20% ETtall) or medium (40% ETtall) irrigation treatment. Based on these results, it appears a crop coefficient of 0.3 (30% of ETrs) may be sufficient for planning and estimating the total water requirements of a large, mixed-species xeric landscape in the Four Corners region. A multi-season field experiment was conducted to monitor the movement of water and nutrient contents under a drip irrigation system. Sweet corn was cultivated at Waimanalo research station of the University of Hawaii at Manoa. Soil organic treatments were three rates of chicken manure and compost replicated three times. The field was under regular tillage during first and third cropping seasons whereas No-Till was adopted during the second cropping season. Soil solutions within and below the crop root zone were collected using suction cup lysimeters. Water samples were collected from the lysimeters weekly or bi-weekly. The soil solution samples were analyzed for NO3, pH and electric conductivity. These soil water samples were also analyzed for the major macro and micronutrients. Multisensor Capacitance Probes (MCPs) were installed at each treatment to monitor soil water content within and below the crop root zone. Each MCP contains 4 moisture sensors at 10, 20, 30, and 50 cm depths who were monitored via a data logger near real-time. The first three sensors (i.e., at 10 through 30 cm depths) monitored water contents within the root zone and the fourth at 50 cm depth monitored water content below the root zone. The sensors were logged at 15 minutes intervals. Soil moisture data was downloaded from the data loggers on weekly and/or bi-weekly basis. This data was analyzed using the water balance approach to determine plant water use and excess water losses below the rootzone. At the end of each cropping season, plant root and shoot samples were collected and analyzed for nutrient concentration. Undisturbed soil cores were collected from each treatment at 10, 20, 30, and 50 cm depths. Soil physical properties including bulk density (BD) and soil total porosity (TP) were determined following standard procedures. The results showed that BD decreased and TP increased with increase in manure and compost application rates. Decreased BD and increased TP result in increased soil water retention. Tension and double ring infiltrometers were used to determine the steady state infiltration rates in each treatment plot. The steady state infiltration rates were used to determine soil hydrological properties, i.e., saturated hydraulic conductivity (Ks) of the soil. The results show that Ks increased with increase in manure application rates. Similar trends were found in compost treatments. Increased Ks makes soil water and hence the dissolved nutrients available for plant uptake. Soil disturbed samples that were collected from the top 15 cm soil layer were processed for soil chemical properties including soil organic matter (SOM), soil organic carbon (SOC), pH, electrical conductivity (EC), and nitrate concentrations. In addition to improving soil aggregation, the organic manure application to this tropical soil increases SOC pools that contribute to the atmospheric carbon dioxide upon tillage and other agricultural practices. An Irrigation Water Requirement Estimation Decision Support System (IWREDSS) a GIS-based version of IManSys was developed for Hawaii Commission on Water Resources Management to use in their water allocation for different water users across the state. IWREDSS produces spatially distributed irrigation requirements and different water budget components. IWREDSS uses a water balance approach to calculate the major field water balance components, e.g., effective rainfall, canopy interception, surface runoff, and water redistribution and extraction by evapotranspiration on a daily basis. IWRDESS was calibrated and validated using published data for Hawaii. Hybrid poplar (cultivar OP-367) had been planted for sawlog production in April. Five irrigation treatments were established in 2000 and were continued through 2008. Irrigation treatments consisted of three treatments using microsprinklers and two using drip tape. The three microsprinkler treatments consisted of one adequately irrigated check (irrigations at 25 kPa soil water tension and 51 mm of water per irrigation) and two lower irrigation treatments (irrigations initiated when the check treatment is irrigated, but with of 34 mm and 17 mm applied per irrigation). The two drip-irrigated treatments were irrigated separately at 25 kPa soil water tension and 51 mm and 25 mm applied per irrigation. Soil water tension was measured at 20-mm depth. The most productive treatments received considerably more water than estimated crop evapotranspiration. Stem volume in the fall of 2007 and stem volume growth from 2000 through 2007 were highest with drip irrigation applying 25 mm of water per irrigation at a soil water tension of 25 kPa. The microsprinkler-irrigated poplar with 34 mm and 17 mm per application had proportionally lower sawlog production that the treatment receiving 51 mm per application. Research and Extension work at Idaho evaluating the performance of Decagon soil water sensors and data loggers was expanded this year. Sensors and data loggers were installed at 4 depths in soils with textures ranging from sandy to heavy silt loam. Sensor readings were periodically compared to soil water content determined by field sampling and gravimetric water content analysis. A field study evaluating 4 levels of irrigation water application under drip and sprinkler irrigation on oilseed production of winter canola was conducted at the Kimberly R&E Center in 2008. Irrigation was added to supply 50, 75, 100 and 125% of estimated ET. Onion plants infected with iris yellow spot virus (IYSV) can progressively lose leaf area, resulting in reduced yield and reduced bulb size. The virus is transmitted by onion thrips (Thrips tabaci). The incidence of IYSV can be increased by inadequate control of onion thrips, which have become increasingly resistant to pyrethroid and organophosphate insecticides. A certain degree of varietal tolerance to thrips and IYSV has been determined. However, management factors such as irrigation, fertilization, and straw mulching that reduce plant stress might reduce the intensity of thrips and IYSV infestations. Onion expression of IYSV, yield, and 50-mm depth soil temperature responses are being determined to irrigation criteria, irrigation system (drip, sprinkler, or furrow), nitrogen fertilizer rate, and straw mulching. Native forb seed is needed to restore rangelands of the Intermountain West. Commercial seed production is necessary to provide the quantity of seed needed for restoration efforts. A major limitation to economically viable commercial production of native forb seed is stable and consistent seed productivity over years. Variations in spring rainfall and soil moisture result in highly unpredictable water stress at flowering, seed set, and seed development, which for other seed crops is known to compromise seed yield and quality. Native forbs are not competitive with crop weeds. Both sprinkler and furrow irrigation could promote seed production, but risk encouraging weeds. Furthermore, sprinkler and furrow irrigation can lead to the loss of plant stand and seed production due to fungal pathogens. By burying drip tapes at 30 mm depth, and avoiding wetting of the soil surface, we hope to assure flowering and seed set without encouraging weeds or opportunistic diseases. Current trials are testing the effects of three irrigation intensities (coordinated with the flower formation, flowering, and seed set of each species) on the seed yield of 13 native forb species. The total irrigation water requirements for these arid land species has been shown to be low, in the range of 100 to 200 mm/year, and varied by species.

Publications

Abbas F, Fares A. 2008. Soil Organic Carbon and CO2 Emission from an Organically Amended Hawaii Tropical Soil. Soil Science Society of America Journal (Accepted). Ahmad A, A Fares, F Abbas, J Deenik. 2008. Nutrient Availability to Plants and their Loss below Root Zone under Chicken Manure Amendments in Hawaii Leeward and Windward Conditions. Soil Science Society of America Journal (In Review). Enciso-Medina, J. M., P. D. Colaizzi, W. L. Multer, and C. R. Stichler. 2007. Cotton response to phosphorus fertigation using subsurface drip irrigation. Applied Engineering Agriculture. 23(3): 299-304. Fares A. 2008 Water management software to estimate crop irrigation requirements for consumptive use permitting in Hawaii. Report submitted to the State of Hawaii Department of Land and Natural Resources Commission of Water Resources Management, Honolulu, HI, 66 pp. Fares A, F Abbas, A Ahmad, JL Deenik, M Safeeq. 2008. Response of Selected Soil Physical and Hydrological Properties to Manure Amendment Rates, Level and Types. Soil Science 173: 522533. Harmsen, E. W., 2007. Small-Scale Rainfall Variability in Western Puerto Rico and its Implications on Agricultural Water Management. Annual meeting SOPCA 2007, Centro de Convenciones de Cataño, Cataño, Puerto Rico, November 15, 2007. Harmsen, E. W., 2007. The Potential Impact of Climate Change on Agricultural Water Resources in Puerto Rico. Segunda Jornada Científica del Colegio de Ciencias Agrícolas, March 16th, 2007. University of Puerto Rico Mayagüez Campus. Lamm, F. R. and A. A. Abou Kheira. Effects of early-season water stresses on corn production. Proc. 29th Annual Intl. Irrigation Assoc. Tech. Conf., Anaheim, California, Nov. 2-4, 2008. Available from Irrigation Association, Falls Church, VA. Paper No IA09-1052. 10 pp. Lamm, F. R., and R. M. Aiken. 2008. Comparison of Temperature-Time Threshold-and ET-based Irrigation Scheduling for Corn Production. ASABE paper no. 084202. Available from ASABE, St. Joseph, MI. 12 pp. Lamm, F. R., D. M. OBrien, D. H. Rogers, and T. J. Dumler. 2008. Using the K-State center pivot sprinkler and SDI economic comparison spreadsheet 2008. In: Proc. Central Plains Irrigation Conference, Greeley, CO., Feb. 19-20, 2008. Available from CPIA, 760 N.Thompson, Colby, KS. pp. 61-70. Lombard, K.A., M.K. ONeill, R.F. Heyduck, B.M. Onken, R.G. Pablo, D. Smeal, R. N. Arnold, A. Ulery, and J. Mexal. 2008. Evaluation of field grown hybrid poplar OP-367 after amending with biosolids. In: ONeill, M.K. (ed). Soil and water conservation research in the arid Four Corners region. Symposium, Soil and Water Conservation Society Annual Meeting. July 27-31. Tucson, AZ. Neibling, W.H. and J. Robbins. 2008. Understanding your water supply options. University of Idaho CIS. In press. Neibling, W.H. and J. Robbins. 2008. Watering your plants during times of drought and restricted water. University of Idaho CIS. In press. ONeill, M.K. and M.M. West (eds.) 2008. Forty-first Annual Progress Report: 2007 Cropping Season. With contributions from R.N. Arnold, D. Smeal, R.F. Heyduck, C.K. Owen, K.D. Kohler, K.A. Lombard. NMSU Agricultural Science Center at Farmington. Agricultural Experiment Station and Cooperative Extension Service. New Mexico State University. Las Cruces, NM. ONeill, M.K. (ed). 2008. Soil and water conservation research in the arid Four Corners region. Symposium, Soil and Water Conservation Society Annual Meeting. July 27-31. Tucson, AZ. ONeill, M.K., R.F. Heyduck, K.A. Lombard, D. Smeal, R.N. Arnold, R.G Pablo, and B.M. Onken. 2008. Sustainable poplar production for multiple uses in the Four Corners. In: ONeill, M.K. (ed). Soil and water conservation research in the arid Four Corners region. Symposium, Soil and Water Conservation Society Annual Meeting. July 27-31. Tucson, AZ. Pereira, A.B., C.C. Shock, B.G. Feibert, and N.A. Villa Nova. 2008. Performance of "Irrigas" for onion irrigation scheduling compared to three soil water sensors. Engenharia Rural. 18:109-114. Qureshi, Z and W. H. Neibling. 2008. Response of Two-row Malting Spring Barley to Water Cutoff under Sprinkler Irrigation. Agric. Wager Manage. doi 0.1016/j.agwat.2008.07.012 Ramírez, V. H., E. W. Harmsen and T. Porch, 2007. Crop Water Stress Index and Yield Components for New Common Bean (Phaseolus vulgaris L.) Genotypes in Greenhouse and Field Environments. Poster presentation. Annual meeting SOPCA 2007. Centro de Convenciones de Cataño, Cataño, Puerto Rico, November 15, 2007. Román-Paoli, E., F. Román, J. Zamora. 2008. Evaluation of microirrigation levels on growth and productivity of avocado trees. J. Agric. Univ. PR. (Accepted). Román-Paoli, E., J. Beaver. 2008. Performance of a Quality Protein Maize variety in a Vertisol. 44th Annual Meeting, Caribbean Food Crop Society. 13-18 July. Miami, Florida Shock, C.C. 2008. The Canon of Potato Science: 31. Irrigation. Potato Research 50:331-333. Shock, C.C., S. Irmak, B. Sanden, L.A. Lima, K. Taylor. 2008. Grower Adoption of granular matrix sensors. ASA/CSSA/SSSA annual meeting, October 5-9, 2008, Houston, TX. Shock, C.C., E.B.G. Feibert, L.D. Saunders, and J. Ishida. 2008. Identification of post-emergence herbicides for use in native forb seed production. Great Basin Native Plant Selection & Increase Project Annual Meeting, Salt Lake, UT, February 12, 2008. Shock, C.C., E.B.G. Feibert, L.D. Saunders, and J. Ishida. 2008. Native forb seed production in response to SDI in 2007. Great Basin Native Plant Selection & Increase Project Annual Meeting, Salt Lake, UT. February 12, 2008. Shock, C.C. 2008. Perspectives on onion irrigation scheduling and drip irrigation. Stress on onion and its impact on ISYV development. 48th annual meeting of the Malheur County and Eastern Idaho Onion Growers Annual Meeting, Four Rivers Cultural Center, Ontario, February 5, 2008. Shock, C.C. 2008. Perspectives on onion irrigation scheduling and drip irrigation. Drip Irrigation Conference, Clearwater Supply. February 6, 2008. Shock, C.C. 2008. Irrigation management for potato. AS Wilcox Potato Conference, Pukekohe, New Zealand, August 28, 2008. Shock, C.C. 2008. Research initiatives. AS Wilcox Potato Conference, Pukekohe, New Zealand, August 28, 2008. Shock, C.C. E.B.G. Feibert, L.D. Saunders., L. Jensen, and K. Mohan. 2008. Management of onion cultural practices as a means to control the expression of iris yellow spot virus. Oregon State University Agricultural Experiment Station, Special Report 1087: 34-51. Shock, C.C. E.B.G. Feibert, and L.D. Saunders. 2008. Microirrigation alternatives for hybrid poplar production, 2007 Trial. Oregon State University Agricultural Experiment Station, Oregon State University Agricultural Experiment Station, Special Report 1087: 84-95. Shock, C.C. and E.B.G. Feibert. 2008. Performance of hybrid poplar clones on an alkaline soil through 2007. Oregon State University Agricultural Experiment Station, Special Report 1087: 100-104. Shock, C.C. E.B.G. Feibert, L.D. Saunders, and N. Shaw. 2008. Subsurface drip irrigation for native wildflower seed production. Oregon State University Agricultural Experiment Station, Special Report 1087: 183-196. Shock, C.C., J. Ishida, and E.B. Feibert. 2008. Native wildflowers grown for seed production show tolerance to conventional postemergence herbicides. Oregon State University Agricultural Experiment Station, Special Report 1087: 197-203. Smeal, D., M.K. ONeill, R.N. Arnold, K.A. Lombard. 2008. Crop coefficients for climate-based irrigation scheduling in semi-arid urban landscapes. In: ONeill, M.K. (ed). Soil and water conservation research in the arid Four Corners region. Symposium, Soil and Water Conservation Society Annual Meeting. July 27-31. Tucson, AZ. Smeal, D., M.K. ONeill, R.N. Arnold, and K.A. Lombard. 2008. Crop coefficients for scheduling irrigations on drought tolerant landscapes. WaterSmart Innovations Conference and Expo. October 8-10, 2008. Las Vegas, NV. Smeal, D., M.M. West, Z.F. Williams, M.K. ONeill, K.A. Lombard and R.N. Arnold. 2008. Efficient irrigation of small plots using a simple, inexpensive micro-irrigation system. Proceedings: ICASALS 2006 Conference: Water in Arid and Semiarid Lands: Innovative Approaches and Informed Decision-Making. Nov. 15-17, 2006. Lubbock, TX. In Press. Smeal, D., Z.F. Williams, M.M. West, M.K. ONeill, and R.N. Arnold. 2008. Drought-tolerant plants for urban landscapes in northern New Mexico. Symposium on Efficient Water Use in the Urban Environment. February 23-24, 2006. Las Cruces, NM. In Press. Smeal, D., M.K. ONeill, R.N. Arnold, and K.A. Lombard. 2008. Crop coefficients for scheduling irrigations on drought tolerant landscapes. WaterSmart Innovations Conference and Expo. October 8-10, 2008. Las Vegas, NV.

Impact Statements

The reduced evaporative cooling under SDI may result in earlier maturity and higher quality cotton, which is a critical consideration in the thermally limited environment of the Northern Texas Panhandle and Kansas. This experiment established a basis and economic justification for selecting the most appropriate irrigation technology for cotton production in thermally limited environments.
Nine combinations of bed design, drip lateral spacing, and drip lateral depths were installed in a subsurface drip irrigation (SDI) system. The wide-bed (twin row) design may result in crop germination comparable to drip lateral spacing in every bed but requiring half the laterals, an important consideration because drip laterals are about two-thirds of total SDI system cost, and poor germination is a major barrier to the adoption of SDI in the Southern Great Plains and elsewhere. These results will provide a basis for improved SDI bed designs and optimal drip lateral installation depth.
Increasing emitter spacing without decreasing crop yield allows for dripline manufacturing and design flexibilities such as emitters with more precise discharge rates that cost more to manufacture. The results also indicate that some emitter clogging would be possible without affecting yields.
Research conducted in avocado trees grown in a high weathered oxisols and tropical environments indicated that trees submitted to high soil water depletion (40-45 kPa) produced the higher yield, and canopy volume. These unique results are important because avocado production has increased consistently in Puerto Rico in the last years.
Producers can select a subsurface dripline installation depth for deep silt loam soils in the Central Great Plains based on their own preferences and constraints without affecting crop production of soybean, sunflower and grain sorghum.
Early season water stress on corn can often be mitigated by relieving the stress near anthesis.
Automated irrigation scheduling such as the Temperature-Time Threshold or BIOTIC method can reduce the amount of individual management and data collection labor required for irrigation scheduling.
Almonds account for a substantial fraction of orchard water use in CA, and a 10% reduction in applied water would have a substantial impact on the states water budget.
Drip-irrigated hybrid poplar production continued to draw interest. Preliminary discussions are underway for significant expansion of poplar production in the area.
Suitable clones for drip-irrigated production in arid and semiarid regions can be identified.
Low tech, gravity fed drip irrigation systems can be used to produce substantial quantities of vegetables that can contribute to nutritional health and economic enhancement.
Landscape conversions from turf to mixed-species xeric perennials can result in substantial water savings of nearly 50%.
Drip-irrigated onion has reduced N inputs compared to furrow irrigated onion with no associated irrigation-induced erosion and associated pollutant runoff. Thirty to 40 percent less water was required using SDI. Therefore, the acreage of drip-irrigated onion has continued to expand and the acreage of furrow irrigated onion has contracted. Onion growers records showed that growers used 115 kg/ha less fertilizer N when irrigating with SDI than with furrow irrigation. Drip irrigation of onion leaves more water in streams and reservoirs. Trends of groundwater nitrate and DCPA are downward in the onion production region of NE Malheur County.
The environmental benefits of drip irrigation are achieved when the practice is economically feasible. Drip irrigation is economically feasible with onion due to improvements in crop yield, quality, and uniformity along with reductions in other input costs related to weed control and fertilization.
Use of daily soil water information at multiple depths with soil water sensors can aid in better water utilization of limited water among farm crops and can save 10% or more on pumping and labor costs due to better irrigation scheduling.
Canola yield increased as additional water was added in the 50 to 100%ET range, and then decreased at the 125%ET level. Use of stored soil water reduced differences among treatments. Yield and water use efficiency was higher under drip irrigation than under sprinkler irrigation.