Brief Summary of Minutes of Annual Meeting

Objective 1. Coordinate the documentation of crop coefficients used in irrigation scheduling.

Colorado

In an effort to improve the calculation of reference evapotranspiration and crop coefficients for irrigation scheduling purposes, a study was carried out in South Eastern Colorado. Quantification of crop water use or evapotranspiration (ETc) is required for efficient irrigation water management. The ASCE-EWRI Standardized Penman-Monteith (PM) evapotranspiration equation (ETsz) has been recommended by the American Society of Civil Engineers (ASCE) to estimate reference ET. The reference alfalfa ET obtained from the standardized ET equation (ETrs) along with alfalfa crop coefficients (Kcr) can be used to estimate a given crop ETc. In this study, the ETsz equation was evaluated using measured alfalfa ET (ETr) from a large monolithic precision weighing lysimeter located near Rocky Ford, Colorado, using data from 2009 to 2012.The performance evaluation of the PM ETsz equation was done for different atmospheric stability conditions for individual years and for all years combined. Also, the evaluation was carried out for multiple alfalfa cutting cycles. The results obtained showed that the equation underestimated measured ETr (−0.04 mm/h (−14%)) for stable atmospheric conditions. Nonetheless, the ETsz values matched closely to those of the lysimeter for unstable atmospheric conditions. Furthermore, somewhat large scattered ETrs values (RMSE of 0.11 mm/h (25.5%)) were observed for neutral atmospheric conditions. The ETrs comparison produced acceptable results for daily time step for years 2009–2011. However, the daily ETrs comparison was not acceptable for the 2012 dataset, which included effects of severe heat advection. Moreover, it was found that the ETsz equation overestimated ETr, the MBE was 0.05 mm/h (18.1%) for the first alfalfa cutting cycle and slightly underestimated (up to −0.02 mm/h (−5.7%)) ETr for the second, third and fourth cutting cycles. Therefore, adjusting (reducing) the value of the constant Cd in the ASCE Standardized ETrs equation for stable atmospheric conditions is recommended; and either adjusting (increasing) the Cd value or developing a different set of crop coefficients for the first cutting cycle of alfalfa, which ultimately helps in improving agricultural water use efficiency. 

Another project is the verification of verification water conservation from deficit irrigation of forage crops in the Upper Colorado River Basin Landsat data and Mapping Evapotranspiration at High Resolution and using Internal Calibration (METRIC™) in scattered pasture fields in Wyoming and Colorado that are being deficit irrigated as part of a Pilot Water Conservation Project.   The water use and therefor Kc values decrease after irrigation is stopped, but the yield difference is not proportional to the decrease in irrigation.   Pasture studied show the yield difference between full irrigated and partial irrigation have consistently (2013-2016) been about 1 ton per acres.  The water use efficiency (i.e. tons/acre-inch) is much lower after the initial cutting, even as temperatures cool in the fall.  

The verification of water conservation from deficit irrigation using METRIC show; 1) Determining water savings from deficit irrigation of riparian pastures is difficult, 2) There is large field-to-field variability in water savings from short-season irrigation (some fields showed little or no water savings), 3) Remote sensing applications can be used to estimate ET and with proper comparison they can be used to estimate water savings from deficit irrigation and fallowing. 4) Both year-to-year and field-to-field information is needed to make a good estimate of water savings from deficit irrigation.  Our recommendations are to obtain history of field including how is it irrigated, what is the pattern of irrigation (has it been irrigated the full season), evaluate topography and location of field, consider water table contribution to ET, use historical Landsat and aerial imagery to estimate baseline ET.  Average seasonal Kc ranged from 0.74 (full irrigation) to 0.46 (deficit irrigation) based on METRIC analysis.

Louisiana

The future work planned from the last state report, indicating work with weighing lysimeters, was not completed due to their state of disrepair and lack of funds to revitalize them.  Instead, work was focused on using alternative methods for estimating crop coefficients.

In 2015, GS-1 (Decagon Devices, Pullman, WA) soil moisture sensors were used to estimate crop coefficients in a sandy clay loam soil for cotton.  The crop coefficients were calculated as the loss of soil moisture on non-rainy and non-irrigated days using a rolling 10-day average to smooth the estimations.  The measured coefficients were validated using the crop coefficients developed for cotton on clay soils using weighing lysimeters (Kumar et al. 2015).  These coefficients were adequate during most of the growing season except on two occasions during the dry summer conditions where the crop coefficient decreased significantly.  Upon further exploration, these two occasions corresponded to two missed irrigation events, indicating that a stress coefficient was introduced.  These same sensors were implemented on two other soil types, silt loam and cracking clay, with less than acceptable accuracy resulting in the inability to calculate coefficients for soybean.  In 2016, the reuse of the sensors resulted in less accurate soil moisture estimations as experienced by inexplicable and drastic shifts of soil moisture readings over short periods of time, sometimes resulting in oscillations or complete shifts in measurements.  As a result, the sensors could be used to make most irrigation decisions, but not for determining crop coefficients.

Missouri

We maintained three real-time weather stations with web access to the information at research facilities in southeast Missouri and continued tests using variable rate irrigation (VRI) to evaluate irrigation treatments for center pivot irrigated rice, corn, and soybean based on evapotranspiration calculated from on-site weather station data. USDA-ARS worked with collaborators at University of Arkansas to finalize publication compiling and analyzing 10 years of on-farm rice water use measurements. Earl Vories collaborated with ARS researchers at Bushland, Texas, Florence, South Carolina, and Stoneville, Mississippi, along with a commercial collaborator, to test ARS-developed system for variable rate irrigation management. Guidelines for VRI prescriptions were refined to avoid runoff.

Montana

Kc used for irrigation scheduling in research and extension is adopted from Idaho Kc documentation and FAO-56. We adjusted Kc according to ground cover and water-critical crop stages. We managed to acquire funding from Montana Wheat and Barley to carry on Local crop coefficient documentation, with no provision for equipment. Thus, we coordinated with other professor in the University by loaning us two Eddy Covariance System installed in farmer spring wheat (Northwestern MT) and barley production fields (Southeastern MT). Data processing and analysis is on-going and we are looking forward to provide our first year’s Kc documentation. Resulting Kc will be associated to crop phenological duration and ground cover on ground and by remote sensing. We anticipate that associating Kc with crop biophysical and physiological stages will boost adoption of Kc for efficient irrigation scheduling. We are hopeful to be able to acquire equipment funding or grants to continue Kc documentation in Montana.

Nebraska

Maximizing the net benefits of irrigated and rainfed agricultural crop production through properly and effectively designed, analyzed, and implemented research-based “agricultural water management programs” on large scales is critical and a necessity in many states in the United States and globally (Irmak et al., 2012). Many areas are experiencing water resource and irrigation allocation and management challenges with associated policy transformations or adjustments to conserve ground and surface water resources (Irmak et al., 2010) and to establish a balance between urban, agricultural, industrial, municipal and other water users. In many parts of the United States, producers and their advisors, as well as state and federal water resources agencies, are challenged to practice conservation methods and use water resources more efficiently while meeting crop water requirements to maintaining high productivity while protecting environmental services. Results from this work will provide important information that will allow producers, urban water managers and resource managers to design and implement water management infrastructure in a manner that is both effective for production and environmentally responsible (Irmak et al., 2012). To engage in and address some of the water availability vs. agricultural productivity issues in Nebraska, an unprecedented effort was undertaken in 2005, and the Nebraska Agricultural Water Management Network (NAWMN) was formed (Irmak, 2006; Irmak et al. 2010; 2012) with substantial positive environmental impacts with over 1,400 farmer cooperators representing about 2 million acres of irrigated cropland and with an average of 2 inches of reduction in water withdrawal for irrigation per growing season since 2005. This kind of large scale comprehensive and coordinated water management program, as well as its real-world impacts, is unprecedented.

The NAWMN teaches and demonstrates farmers how to utilize soil moisture monitoring and crop water use estimates from either ETgages or weather station climate data in their practices to enhance irrigation water management and crop production efficiency. The use of climate information [precipitation, temperature, reference (potential) evapotranspiration, crop coefficients, and actual crop evapotranspiration] has also been taught in the NAWMN programs. As a result, the Nebraska producers have been adopting these tools and information in their irrigation management practices.

Texas

Crop coefficients for sunflowers in the Texas High Plains have been developed based upon work conducted at the USDA-ARS lysimeter facility at Bushland, TX  (Howell, et al., 2015). Comparisons of ASCE standardized reference ET calculated using hourly and daily data, and for short and tall reference crops, and comparison with FAO 56 reference ET indicate that relationships between reference ET calculated by the different methods varied significantly from one year to the next. This climate effect means that conversion of crop coefficients for use with the different ET equations will not be straightforward.

Because ET measurements and estimates by various methods often are compared with direct measurement of ET by large weighing lysimeters, and crop coefficients often are developed with data from large weighing lysimeters, emphasis has been placed on the importance of good lysimeter design and management for accurate ET measurement. However, much less attention has been dedicated to guidelines for data collection, processing, analysis, and quality assurance / quality control (QA/QC) for lysimeter data. Improper processing and interpretation of data and management events can lead to substantial errors. Data from large lysimeters at the USDA-ARS Conservation and Production Laboratory (CPRL) in Bushland, Texas, were used to demonstrate that indiscriminate application of smoothing functions and misinterpretation of lysimeter data can lead to significant errors and flawed conclusions.

Understanding and judicious application of recommended techniques and QA/QC procedures can help to minimize errors in processing lysimeter datasets. [Reference: Marek, G.W., S.R. Evett, P.H. Gowda, T.A. Howell, K.S. Copeland, R.L. Baumhardt. 2014. Post-processing techniques for reducing errors in weighing lysimeter evapotranspiration (ET) datasets. Transactions of the ASABE, Vol. 57 (2):499-515.]  These recommendations have been used in subsequent studies using lysimeter-based ET data; selected recent publications are listed in the “Refereed Journal Articles” section of this report.

Utah

Some of our research concerns irrigation scheduling and management when water is limited, as is often the case in many parts of Utah. Much of our research concerns deficit irrigation of pasture.  Pasture Short-Season Irrigation

Research to determine potential water savings for deficit irrigation has been conducted at the Intermountain Irrigated Pasture Project site in Lewiston, Utah (41°57'4.54"N, 111°52'20.90"W, 4,503 feet elevation) since July 2013 and at Panguitch, Utah (37°52'8.29"N, 112°26'11.35"W, 6,547 feet elevation) beginning in 2016.  The Panguitch location is higher in elevation and with a deep water table well below crop rooting zone.  The objectives of the research are to: 1) determine the potential water savings (decreased consumptive use) from shortened irrigation season of pastures, 2) determine water use efficiency of pasture during the growing season, 3) assess impact on yield and health of pastures from deficit or no irrigation during single and multiple irrigation seasons, and 4) assess fertilizer effects on yields of deficit irrigated pastures. Five irrigation levels were used in the research; no irrigation, irrigation through approximate dates of May 31, June 30, July 31, August 31, and September 30.  The Lewiston pasture studies have location has a water table that varies between 40 and 50 inches deep.  This water table contributes to pasture ET in the deficit irrigated plots. New this year is the addition of Acclima TDR-315L soil moisture sensors banks at 15 locations.  The time domain reflectometer systems have provided accurate and consistent hourly data to determine crop water use and crop coefficients. 

Washington

We have compiled Kc values from several different sources and compared them.  These include:

• An old compilation of Kc values used in Washington state irrigation scheduling tool, WISE.
• Crop coefficients modified to the ASCE Standardized equation from AgriMet
• Crop coefficients fit to the above data.
• UC Davis crop coefficients modified to alfalfa ET.

 Conclusions: They are all different!

They have different reference equations, different reference crops, different growing seasons, optimized for different climates, and different varieties.  This is a large problem since it limits the usefulness of evapotranspiration research.  It points to either the method of estimating reference ET not being adequate to account for weather and climatic differences, or differences and errors in the research methods used to estimate crop coefficients.  It is most likely the former.

Wyoming

Currently, there is no information is available on the crop coefficients (Kc) for different crops under Wyoming climate and management practices. PI is planning to purchase one Bowen Ration Energy Balance System (BREBS) that will be installed at Powell Research and Extension Center (PREC) for actual evapotranspiration measurements and the development of Kc values for different crops.

Objective 2. Coordinate efforts to promote adoption of improved irrigation scheduling technology, including computer models based on crop coefficients and ETref, remote sensing and instrumentation that will help producers more efficiently apply irrigation water.

Arkansas

Since 2014 an effort to promote Irrigation Water Management Practices has been used to provide educational opportunities and training for county Extension agents, agency personnel, and irrigators.   In 2016 the program has expanded to 30 demonstrations on 27 farms, mostly furrow irrigated rice and corn.  Each site has flow measured, computerized hole selection, soil moisture monitoring and most had surge irrigation practices applied.  IWM fields are compared to a control field without IWM (in the case of rice it was compared to a flood irrigated field).  Each site was visited as necessary (generally at least three to ten times during the season) and monitored remotely and with close collaboration with the county agent or the farmer directly. 

Soil moisture sensors are a primary method to schedule irrigation in rice, which has a very shallow rooting system and is very sensitive to water stress relative to other row crops.  This season the results were mixed, in many cases water use was reduced, but yields may have been more or less than the control field.  Unseasonably wet weather and limited irrigation requirements as well as other production related factors impacted the 2017 growing season.  One primary objective in 2016 was to compare furrow irrigated rice to flood irrigated rice.  No significant difference in yields (p=0.52) or water use (p=0.17) was found statistically, however water use was 10-21% less and yields for flooded rice were 4% higher on average.  This data suggests considerable potential for furrow irrigated rice as an alternative to flood irrigation and is the first multi-site study of its kind to document yield and water use differences between the two production systems.  Considerable work and resources will be needed to confirm results found in 2016.  Through these demonstrations agents and irrigators learn how to implement IWM practices on row crops and the program is providing key data for a novel and poorly understood production system for rice.

Colorado

            Extension South Eastern Colorado (Osborn Blake).  Accurate weather station data plays a critical role in the development and use of many water management tools used and recommended to others. First, as a member of a team working to develop crop coefficients through the use of a weighing lysimeter, it is critical that we have accurate weather data for calculating evapotranspiration for comparison with measured data. Second, I rely on local weather station data from the Colorado Agricultural and Meteorological Network (CoAgMet) to schedule irrigations for homeowners (through the Lawn Irrigation Self Audit program) as well as large agricultural producers using an irrigation scheduling tool developed by Colorado State University. As a field based research scientist, I rely heavily on the CoAgMet weather station network to provide me data on crop ET for use in irrigation scheduling tools.

Regarding the irrigation scheduling tool WISE (http://wise.colostate.edu/) developed by Dr. Allan Andales, efforts are underway to incorporate remote sensing derived actual stress coefficients in the dual crop coefficient approached from FAO Paper-56.

Louisiana

In 2015 and 2016, various soil moisture sensor products were implemented in research and demonstration situations to determine their ability for aiding in scheduling irrigation and end-user responses to using them.  In the first year, at least one sensor type had acceptable performance across all locations.  Additionally, producer feedback was positive.  However, reuse of the sensors in the second year resulted in less than accurate soil moisture readings.  In some situations, irrigation was delayed for too long during the critical moisture period due to the sensors failing to accurately measure moisture throughout the full drying curve.  Additionally, approximately 10% of sensors failed during the second year.  Sensors will be evaluated for life expectancy, taking note of failures over time. 

Demonstrations showed that trust in the sensor data was relative to whether sensors failed at the site location.  Both years were considered to have more rain than a normal year, resulting in little water savings from using the technology.  However, producers were able to understand that they could skip irrigation events during normal years by using the sensors. 

In 2016, an irrigation scheduling spreadsheet was developed for Louisiana.  This spreadsheet conducts a daily soil water balance during the growing season.  Though each detail is customizable by the user, suggested inputs for soil characteristics and plant information are provided from existing literature that was narrowed for Louisiana conditions when possible.  Testing of the spreadsheet occurred during the 2016 crop season so that adjustments in functionality and utility could be made.  It is anticipated that the manual will be written this winter and the spreadsheet can be released before the 2017 crop season. Hope remains that the weather station network will also be working so that rainfall and evapotranspiration information, both required for the spreadsheet’s operation, will be readily available to producers.

Texas

The most recent Farm and Ranch Irrigation Survey indicates that less than 15% of farms use measurement based methods for scheduling irrigation. Technologies for scientific irrigation scheduling have been available for decades but their adoption rates have remained poor. One potential reason for the low adoption lies in the effort required to use the technology. Deriving value from these tools requires using multiple, separate sources of information and growers must do the data integration. The AgGateway.org Precision Ag Irrigation Leadership (PAIL) project team is seeking to develop an industry-wide standard data format that will simplify data integration, and ultimately increase adoption of technologies, including irrigation scheduling technologies. The project team has developed a set of process models (Use Cases, User Stories, and BPMN diagrams) describing the irrigation management process. Based on these process models, the team designed a robust data model that incorporates relevant data flows and messages. The data model is rendered as an XML Schema and, when the data standard is published, this schema will be available publicly. Two field trials will serve to verify the efficacy of - and demonstrate the utility of - the PAIL standard, and will serve as a foundation for documentation and training materials. Charles Hillyer is a member of the AgGateway PAIL project team.

Dana Porter and Thomas Marek completed a project, “Higher Integration Networking, Texas High Plains Evapotranspiration Network,” sponsored by the Texas Water Development Board via Panhandle Regional Planning Commission. This work supported a graduate student and provided public access to adapted and user-friendly packaged ET-based crop water use information and related agricultural meteorological data. End users of the information included agricultural irrigators; agricultural, environmental and other research programs; water resources managers/agencies; crop insurance companies and agencies (TDA, USDA-Risk Management Agency); municipalities, turf managers, homeowners; environmental consultants and researchers; and educators. While the tools and resource materials are broadly applicable to a wide range of audiences and conditions, the ET based crop water use data are regionally focused in the Texas High Plains (Panhandle and South Plains) where the majority of irrigation water in the state is used, as well as portions of the Rolling Plains and West Texas. The products of this effort support Regional Water Planning agricultural water conservation strategies.

An irrigation scheduling tool incorporating cotton crop growth model(s), local weather data (rainfall and crop ET), soil moisture balance, and irrigation management recommendations based on long-term applied research has been developed and is being beta tested. The Dashboard for Irrigation Efficiency Management (DIEM) package prescribes a season-long, field-specific irrigation schedule that optimizes yield and water use efficiency based on total water (rainfall and irrigation) availability. As the growing season progresses, DIEM users can update their irrigation schedule recommendation based on real-time weather, soil moisture, and other field observations (Bordovsky, et al., 2015). Beta testing will be expanded during the 2017 crop season. This project is a collaboration of a team under the leadership of Jim Bordovsky (PI, Texas A&M AgriLife Research), Jim Wall and Keith Biggers (Texas Center for Applied Technology), and Dana Porter.

Educational events, including irrigation workshops, webinars, invited presentations, posters and oral presentations at conferences; news releases and media outreach; and internet-base information delivery promoted efficient irrigation management using ET-based scheduling and other technologies as appropriate. While in-person attendees benefitted from interactions with others at conferences and had opportunities to visit with speakers and vendors, extensive local media coverage promoted highlights of the events and availability of educational resources throughout the region. Selected educational events, presentations and packages are listed below.

• Porter, Dana. 2016. High Plains Irrigation Conference. Amarillo, Texas, February 4, 2016.
• Marek, Thomas. 2015. Workshop: practical considerations in establishing and maintaining a evapotranspiration weather station network to support research programs. Texas A&M AgriLife Research and Extension Center Seminar, Vernon, TX. September 23, 2015.
• Marek, Thomas. 2016. Center Pivot Irrigation Workshop. Delta States Irrigation Conference, Memphis, TN. January 13, 2-16.
• Porter, Dana. 2015. Evapotranspiration: Applications in water management research to address emerging water issues. Texas A&M AgriLife Research and Extension Center Seminar, Vernon, TX. September 23, 2015.
• Porter, Dana. 2016. Cochran County Irrigation Workshop. Morton, TX, April 3, 2016.
• Porter, Dana. 2016. Irrigation Management for Cotton Production. Texas A&M AgriLife North Region Cotton Field Day, Lubbock, TX. August 4, 2016.

Montana

Research on making every drop count was conducted from 2014-recent in NWARC (J. Torrion and R.N Stougaard, Northwestern Ag Research Center) by setting up research where Genetics x Environment x Management association was evaluated. This included eight spring wheat varieties x 2 Soil Types x six irrigation treatments (100ET, early terminations based from 100ET treatment [minus 1, 2, and 3 irrigation event/s early cut off], deficit, and dryland).

Brennan variety is the least responsive in both dryland and irrigated environment, whereas Volt showed high yield in dryland, and showed response in irrigation supplementation. However, additional response was not observed at the high irrigation application (FullIrr[100ET] and FullIrr-1). Solano, which is a popular dwarf variety in NW MT, responded in drought stress, but not very responsive to supplemental irrigation. Overall, 100ET is not superior compared with the early cut off irrigation terminations or the deficit irrigation on imposed water stress.

Results of this research were presented during winter grower’s meeting (60 farmers); 2014 NWARC field day (120 people); 2015 NWARC field day (100 people); and 2015 NARC field day (65 people) and many more early next year. Extension events include the use of Kc, Reference ET, knowing your soil types, and genetic-specific response to the various irrigation strategies in terms of yield and quality. The use of granular-matrix sensors (watermark) was also discussed.

Missouri

The University of Missouri Extension developed an online application to help farmers produce higher crop yields by improving irrigation management. The program was released in 2015. The Crop Water Use application can be run on an office computer or smartphone. To register, go to http://cropwater.org.  The program is designed to simplify calculations required for tracking soil moisture in fields.  Crop water use is estimated from weather data from a network of agricultural weather stations across the state. In 2016, Missouri farmers used the program on 398 fields. The application saves farmers time by automatically entering weather information for each field and making daily calculations used for irrigation planning. Evapotranspiration (ETo) is calculated using the standardized short crop Penman-Monteith equation. ETo is multiplied by a crop coefficient, which is specific for the crop and growth stage.

Nebraska

Maximizing the net benefits of irrigated and rainfed agricultural crop production through properly and effectively designed, analyzed, and implemented research-based “agricultural water management programs” on large scales is critical and a necessity in many states in the United States and globally (Irmak et al., 2012). Many areas are experiencing water resource and irrigation allocation and management challenges with associated policy transformations or adjustments to conserve ground and surface water resources (Irmak et al., 2010) and to establish a balance between urban, agricultural, industrial, municipal and other water users. In many parts of the United States, producers and their advisors, as well as state and federal water resources agencies, are challenged to practice conservation methods and use water resources more efficiently while meeting crop water requirements to maintaining high productivity while protecting environmental services. Results from this work will provide important information that will allow producers, urban water managers and resource managers to design and implement water management infrastructure in a manner that is both effective for production and environmentally responsible (Irmak et al., 2012). To engage in and address some of the water availability vs. agricultural productivity issues in Nebraska, an unprecedented effort was undertaken in 2005, and the Nebraska Agricultural Water Management Network (NAWMN) was formed (Irmak, 2006; Irmak et al. 2010; 2012) with substantial positive environmental impacts with over 1,400 farmer cooperators representing about 2 million acres of irrigated cropland and with an average of 2 inches of reduction in water withdrawal for irrigation per growing season since 2005. This kind of large scale comprehensive and coordinated water management program, as well as its real-world impacts, is unprecedented.

The NAWMN teaches and demonstrates farmers how to utilize soil moisture monitoring and crop water use estimates from either ETgages or weather station climate data in their practices to enhance irrigation water management and crop production efficiency. The use of climate information [precipitation, temperature, reference (potential) evapotranspiration, crop coefficients, and actual crop evapotranspiration] has also been taught in the NAWMN programs. As a result, the Nebraska producers have been adopting these tools and information in their irrigation management practices.

In 2005, there were 15 farmer cooperators in the Network and one NRD as partners. As of end of 2016, the number of active growers who joined the Network has increased to more than 1,500. By 2016, the NAWMN partners represented 1.8 million acres of irrigated land area. Due to the information and strategies taught and tools and technologies demonstrated in the Network, participants are changing their behavior in terms of how they manage irrigations and Network is having significant impacts in terms of conserving water and energy resources statewide. Since 2005, the reduction in the amount of water withdrawal for irrigation in corn and soybean fields farmed by the NAWMN participants has been averaging as 2.1 inch per growing season. The number of NRD partners has increased from one in 2005 to 18 (out of 23) in 2014. In 2015 and 2016, over 30 presentations have been made to deliver additional information to the growers. Additional soil moisture technologies have been researched and the information has been delivered to the NAWMN cooperators.

Oklahoma

Efforts were continued at Oklahoma State University toward promoting the use of sensor-based technologies to improve irrigation scheduling:

• A multistate proposal (Oklahoma, Texas, and Kansas) was awarded by USDA-NRCS Conservation Innovation Grant. This $770,000 grant will support the development of demonstration sites and extension material on use of sensor technologies over the next three years. Our activities in this field was highlighted in a recent White House publication and we were invited to the World Water Summit that was held at the White House on March 21, 2016.
• Different types of sensors were installed at three demonstration sites (in cooperation with agricultural growers) and two research stations in Southwest and Panhandle regions of Oklahoma. A local dealer installed another type of sensors at two of the demonstration sites to allow for a comparison between sensor types and installation methods.
• Information on science-based irrigation scheduling was disseminated by presenting at four meetings with scientific community and fifteen field days and meetings with growers and crop consultants. The total number of extension contact hours (face-to-face interaction with clientele) was 434 hours during the reporting period.
• The 3rd Oklahoma Irrigation Conference was organized in March 2016. Invited irrigation specialists from Oklahoma, Kansas, and Texas presented on different aspects of irrigation management. One hundred eighteen (118) people attended this conference (about 50% more than last year). About 68% of the participants in the post-conference survey rated it highly, agreeing that the information provided was helpful and timely.

Utah

We have developed a gridded ET Model (GridET) to use provide a spatial potential ET data that can be utilized with GIS software.  The methodology and software were developed using the ASCE Standardized Reference Evapotranspiration equation with input climate drivers from the North American Land Data Assimilation System (NLDAS) gridded weather forcing dataset and a digital elevation model. The method provides potential ET data at locations not adequately represented by electronic weather stations.

Washington

We have developed a simple, user friendly irrigation scheduler that is designed first for usability.  It works on mobile phones as well as any web browser (http://weather.wsu.edu/ism).  There is a full-page version as well as a small screen version for mobile phones.  It has a one week forecast.  It does push notification (text and email alerts).  It works with most all of the weather networks in the Western US to automatically pull ET data, calculate reference ET, and apply the Kc values and compute the soil water balance.  There is a functional Android App, and there will be an iPhone app running by next spring.

            The code is open source (written in PHP and MySQL).  The code is available for download at http://irrigation.wsu.edu/Content/ism.zip.  There is also a user’s manual at http://weather.wsu.edu/ism/ISMManual.pdf.   We will help support the inclusion of additional weather networks.  

            We currently have an Android app, and are developing an iPhone app that should be available by next spring.

Figure 1. Map of the weather stations that work with the mobile irrigation scheduling tool.  Also works in Alberta, Canada.  The numbers on the balloons are the number of fields set up on that station.

Wyoming

Research and extension efforts are made to develop the Wyoming Agricultural Water Management Program (Wyo-AWMP) to effectively manage the agricultural water resources in Wyoming. Currently, producers across the state do not have access to basic climate and evapotranspiration data for different crops (mainly sugarbeet, barley, drybeans, winter wheat, and alfalfa) for irrigation scheduling, under the Wyoming climate and management practices. When PI (Vivek Sharma) joined the University in April, 2016, University of Wyoming weather stations at five locations were not under working conditions. PI worked on the weather station and now all the weather station are under working condition. In addition, PI is also working with Wyoming State Office to install addition five more weather stations especially in the northern Wyoming, where current no weather station exist. All the data from aforementioned weather stations will be disseminate to Wyoming citizen through University of Wyoming Extension web platform (work under process). PI also started extension activities (e.g. field days and mini field days) to promote the use of soil moisture sensors for irrigation scheduling. However, further research is required to check the accuracy of different available soil moisture sensors according to Wyoming soil type.

Objective 3. Coordinate the development of quality control (QC) procedures for weather data used for irrigation scheduling.

Louisiana

The original LSU AgCenter weather station network continues to be a work in progress.  There has been commitment from personnel to finalize the installations and calibrations before the end of 2016.  There has been no update as to whether the LSU AgCenter website, which was re-released in February under a new software system, will be ready for distributing the data to the public.  Once this network goes live, talked will occur to incorporate irrigation scheduling capabilities either by funneling the data into a standalone product or incorporating irrigation scheduling into the weather network’s reporting software.  The LSU AgCenter IT department stopped negotiations for allowing the Bureau of Reclamation to conduct quality control, citing security issues with outside entities accessing the state’s network.  Quality control will have to be conducted in-house.

Texas

A previously reported statewide assessment of evapotranspiration networks in Texas provided an inventory of capabilities of existing networks to address agricultural irrigation scheduling and water planning needs. Operations and management, site and instrumentation issues, data QA/QC and other issues were investigated, and recommendations for improvements continue to be used in informing water and natural resources agency decisions regarding ET and other data used in irrigation scheduling, as well as in development of new irrigation scheduling

Utah

We are evaluating gridded weather data such as the NLDAS data to provide better estimation of potential ET in locations not represented by weather stations.  We are evaluating sources and methods to determine spatial gridded precipitation (Daymet, PRISM, gridding methods) to use with METRIC and other estimates of ET to determine effective precipitation and depletion.  Weather data quality control procedures are implemented by the Utah Climate Center, State of Colorado, and State of Wyoming.

Adhikari, Diganta,  Dan Berne, R Andres Ferreyra, Charles Hillyer, Steve Melvin, Bart Nef, R Andres. Data Exchange Standard for Precision Irrigation. 2016 Annual International Meeting of the ASABE. Orlando, FL. July 2016.

Amatya, D.M., S. Irmak, P. Gowda, G. Sun, J.E. Nettles and K.R. Douglas-Mankin. 2016. Ecosystem evapotranspiration: Challenges in measurements, estimates and modeling. Transactions of the ASABE 59(2): 555-560.

Anapalli, Saseendran S., Lajpat R. Ahuja, Prasanna H. Gowda, Liwang Ma, Gary Marek, Steven R. Evett, Terry A. Howell. 2016. Simulation of crop evapotranspiration and crop coefficients with data in weighing lysimeters. Agricultural Water Management 177 (2016) 274-283.

Bordovsky, James P., James Wall, Dana Porter, and Keith Biggers. 2015. Dashboard for Irrigation Efficiency Management. Texas A&M AgriLife Research, College Station, TX. Available at: http://twri.tamu.edu/media/629228/40-diem-81115.pdf.

Djaman, K., A.B. Balde, L. Diop, K. Futakuchi and S. Irmak. 2016. Analyses, calibration and validation of evapotranspiration models to predict grass-reference evapotranspiration in the Senegal River Delta. Journal of Hydrology 8:8294. dx.doi.org/10.1016/j.ejrh.2016.06.003.

Gaspar, J. C. G. Henry, P. B. Francis, L. Espinoza, M. Ismanov, S. Hirsh, A. Horton and H. James.  2016. The Effects of Deep Tillage and Gypsum Amendment, Across a Range of Irrigation Deficit for Furrow Irrigated Soybeans in Three Different Arkansas Soil Types.  Arkansas Soybean Research Studies 2014. Research Series 631.  University of Arkansas, Division of Agriculture, Arkansas Agricultural Experiment Station.  May 2016.  pp 150-155.

Gowda, Prasanna H.,  Terry A. Howell, Jose L. Chavez, George Paul, Jerry E. Moorhead, Daniel Holman, Thomas H. Marek, Dana O. Porter, Gary H. Marek, Paul D. Colaizzi, Steve R. Evett, David K. Brauer. 2015. A decade of remote sensing and evaportranspiration research at the USDA-ARS Conservation and Production Research Laboratory. 2015 ASABE / IA Irrigation Symposium: Emerging Technologies for Sustainable Irrigation - A Tribute to the Career of Terry Howell, Sr. Conference Proceedings (doi:10.13031/irrig.20152143458).

Gowda, Prasanna, Terry Howell, Louis Baumhardt, Dana Porter, Thomas Marek, and Vinay Nangia. 2016. A user-friendly interactive tool for estimating reference ET using ASCE Standardized Penman-Monteith Equation). Applied Engineering in Agriculture. 32(3): 383-390.

Hao, B., Xue, Q., Marek, T. H., Jessup, K. E., Hou, X., Xu, W., Bynum, E. D. and Bean, B. W. (2016), Radiation-Use Efficiency, Biomass Production, and Grain Yield in Two Maize Hybrids Differing in Drought Tolerance. J Agro Crop Sci, 202: 269–280. doi:10.1111/jac.12154.

Henry, C G., Hirsh, S. L., Anders, M. M., Vories, E. D., Reba, M. L., Watkins, K.B., and Hardke, J. T. 2016. Annual Irrigation Water Use for Arkansas Rice Production. J. Irrig. Drain Eng., 10.1061/(ASCE)IR.1943-4774.0001068 , 05016006.

Henry, C. G. W. M. McDougall, and M. L. Reba.  2016.  A Study of Arkansas Irrigation Pumping Plant Efficiency.  Arkansas Soybean Research Studies 2014.  Research Series 631.  University of Arkansas, Division of Agriculture, Arkansas Agricultural Experiment Station.  May 2016.  pp 156-158. 

Henry, C. G., G.S. Sartori.  L. Espinoza, P. Francis, J. Gaspar, A. P. Horton, S. M. Hirsh.  2016. Deep Tillage and Gypsum Amendment on Fully, Deficit Irrigated and Dryland Soybeans.  Accepted for publication in the Agronomy Journal. 

Henry, C. G., K. B. Watkins, R. U. Mane and G. L. Stark.  2016.  Vertical Hollow Shaft Motors for Irrigation: Does Premium Efficiency Payback?  Presented at the 2016 ASABE Annual International Meeting, Orlando, Florida, July 17-20.  Paper Number 2459984.  ASABE St. Joseph, MI. 

Henry, C., C. Declerk, R. Wimberly, M. Daniels, A. Sharpley, C. Hallmark, and J. Hesselbein.  2016.  Arkansas Discovery Farms: Improving Irrigation Efficiencies in Soybean with Pipe Planner Design and a Surge Valve.  Arkansas Soybean Research Studies 2014.  Research Series 631.  University of Arkansas, Division of Agriculture, Arkansas Agricultural Experiment Station.  May 2016.  pp 172-175

Howell, Terry, Steve Evett, Judy Tolk, Karen Copeland, and Thomas Marek. 2015. Evapotranspiration, water productivity and crop coefficients for irrigated sunflower in the U.S. Southern High Plains. Agricultural Water Management 162:33-46.

Kandpal, V. and C.G. Henry.  2016.  A Review of Improving Efficiencies in Furrow Irrigation.  Presented at the 2016 ASABE Annual International Meeting, Orlando, Florida, July 17-20.  Paper Number 2462974.  ASABE St. Joseph, MI. 

Marek, G.W., Gowda, P., Evett, S.R., Baumhardt, R.L., Brauer, D.K., Howell, T.A., Marek, T.H., Srinivasan, R. 2015. Evaluation of SWAT for estimating ET in irrigated and dryland cropping systems in the Texas High Plains. ASABE Annual International Meeting. CDROM: Paper#152141855.

Marek, G.W., Gowda, P., Evett, S.R., Baumhardt, R.L., Brauer, D.K., Howell, T.A., Marek, T.H., Srininvasan, R. 2016. Calibration and validation of the SWAT model for predicting daily ET over irrigated crops in the Texas High Plains using lysimetric data. Transactions of the ASABE. 59(2):611-622 doi:10.1303/trans.59.10926.

Marek, G.W., Gowda, P., Evett, S.R., Baumhardt, R.L., Brauer, D.K., Howell, T.A., Marek, T.H., Srininvasan, R. 2016. Estimating evapotranspiration for dryland cropping systems in the semiarid Texas High Plains using SWAT. Journal of the American Water Resources Association. 52(2):298-314.

Marek, Gary, Prasanna Gowda, Thomas Marek, and David Brauer. 2016. Estimating preseason irrigation losses by characterizing evaporation of effective precipitation under bare soil conditions using large weighing lysimeters. Agricultural Water Management 169:115-128.

Marek, Gary, Prasanna H. Gowda, Thomas Marek, Brent Auvermann, Steve Evett, Paul Colaizzi, and David Brauer. 2016. Estimating preseason irrigation losses by characterizing evaporation of effective precipitation under bare soil conditions using large weighing lysimeters. Agricultural Water Management 169:115-128. May 2016.

Marek, Gary, Prasanna H. Gowda, Thomas Marek, Dana Porter, Louis Baumhardt, and David Brauer. 2016. Modeling long-term water use of irrigated cropping rotations in the Texas High Plains using SWAT. Irrigation Science, September, 2016.

Moorhead, J.E., Gowda, P., Hobbins, M.T., Senay, G.B., Paul, G., Marek, T.H., Porter, D.O. 2015. Accuracy assessment of NOAA gridded daily reference evapotranspiration for the Texas High Plains. Journal of the American Water Resources Association. 51(5):1262-1271. DOI: 10.1111/1752-1688.

Moorhead, Jerry, Prasanna Gowda, Gary Marek, Dana Porter and Thomas Marek. 2016. Spatial uniformity in sensitivity coefficient of reference ET in the Texas High Plains. Applied Engineering in Agriculture, Vol. 32(2): 263-269  

Moorhead, Jerry. 2015. Lysimetric Evaluation of Eddy Covariance and Scintillometer Systems for the Texas High Plains. Dissertation for completion of a Doctor of Philosophy Degree, Texas Tech University Department of Plant and Soil Science, Lubbock, TX. (Graduate committee: Stephen Maas, Prasanna Gowda, Glenn Ritchie, Chuck West, Thomas Marek, Dana Porter, and Mark Sheridan).

Porter, Dana O., Danny Rogers, David Brauer, Thomas H. Marek, Prasanna H. Gowda, Freddie Lamm, James Bordovsky, Terry A. Howell, Sr. 2015. Promoting Efficient Water Management through Effective Outreach Education in the High Plains and Beyond: Role of the Ogallala Aquifer Program. ASABE Paper Number 2143456. ASABE / IA Irrigation Symposium, “Emerging Technologies for Sustainable Irrigation”, Long Beach, California, November 10 – 12, 2015.

Porter, Dana, Dan Rogers, Jonathan Aguilar, Jourdan Bell, Thomas Marek, Saleh Taghvaeian, Bridget Guerrero, Gary Marek, Tiffany Dowell Lashmet, Freddie Lamm, Kay Ledbetter, Prasanna Gowda, Jim Bordovsky, 2016. OAP Technology Transfer: Educating Stakeholders in Agricultural Water Management Issues, Technologies and BMPs. USDA-ARS Ogallala Aquifer Program Annual Meeting, Amarillo, TX. March 9, 2016.

Porter, Dana, Kevin Wagner, and Victor Gutierrez. 2016. South Texas Irrigation Training Program Manual. Texas Water Resources Institute Publication EM-121. Texas A&M University System, College Station, TX.

Sharma, V., A. Kilic, and S. Irmak. 2016. Impact of scale/resolution on evapotranspiration from LANDSAT and MODIS images. Water Resources Research 52: 1-20. doi:10.1002/2015WR017772.

Sharma, V., J. Heitholt and M. A. Islam. Evapotranspiration: Basics, Terminology and its Importance. University of Wyoming Extension, B-1293.

Stevens, G., and Zach Straatmann. 2016.  Crop water use program for irrigation. University of Missouri Extension Service Bull. MP800.

Straatmann, Zachary. 2016.   Interface design and field validation of the Crop Water Use Application. MS Thesis. University of Missouri. Columbia, MO. Adviser: G Stevens.

Subedi A., J.L. Chávez, and A. Andales. 2016. "ASCE-EWRI Standardized Penman-Monteith Evapotranspiration (ET) Equation Performance in Southeastern Colorado." Agricultural Water Management. Accepted on June 30, 2016. Online publication: 24-AUG-2016. DOI information: 10.1016/j.agwat.2016.07.002. In Press.

Vories, E., W. Stevens, M. Rhine, and Z. Straatmann. 2016. Investigating irrigation scheduling for rice using variable rate irrigation.  Agric. Water Mgt. doi:10.1016/j.agwat.2016.05.032

Wang, J., A.L. Kessner, C. Aegerter, A. Sharma, . Judd, B. Wardlow, J. You, M. Shulski, S. Irmak, A. Kilic, and J. Zeng, 2016. A multi-sensor view of the 2012 Central Plains drought from space. Front. Environ. Sci., 4(45): 1-13. 20 June, 2016. http://dx.doi.org/10.3389/fenvs.2016.00045.

Weeks, W., Popp, M.P., Salmeron, M., Purcell, L., Gbur, E.E., Boruland, F.M., Buehring, N.W., Earnest, L., Fritschi, F.B., Golden, B.R., Hathcoat, D., Lofton, J., McClure, A.T., Miller, T.D., Neely, C., Shannon, G., Udeigwe, T.K., Verbree, D.A., Vories, E.D., Wiebold, W J., Purcell, L.C. 2016. Diversifying soybean production risk using maturity group and planting date choices. Agron. J. 108(5):1917-1929.