Brief Summary of Minutes of Annual Meeting

see attached minutes

The committee held its third annual meeting on March 27, 28, and 29, 2006 in Ames, IA (USDA-ARS National Soil Tilth Lab) in coordination with the ADMSTF (Ag. Drainage Management Systems Task Force) meeting ,held at the same location on March 29 and 30, 2006. Individual State Reports IA (Iowa State University) Submitted by Matt Helmers Recent research and extension efforts at Iowa State University relative to drainage design and management practices to improve water quality have centered on nutrient export from tile drainage systems and nutrient management practices to minimize this export of nutrients, specifically nitrate-nitrogen. In addition, work is beginning on evaluating drainage management practices and cropping practices as to their impacts on drainage volume and drainage water quality. Two drainage water management sites are planned to be installed in 2006. One is a field scale (>20 acres) site in central Iowa and the second site is in southeast Iowa. Water quality and subsurface drainage volumes will be monitored from these sites. Work continued on summarizing drainage water quality data. For the four-year study (2001-2004) at the Gilmore City research site in Pocahontas County, applying liquid swine manure at the rate of 150 lb N/acre before both corn and soybeans did not increase either corn or soybean yields compared to 200 lb N/ac of manure applied every other year before corn. In addition, the total of 300 versus the 200 lb N/ac two-year-rate resulted in nitrate-N concentrations in tile drainage increasing on average from 17 to 23 mg/L, a 35% increase that was statistically significant. For a four-year N application timing study at the Gilmore City water quality research site (2001-2004; a study that is being continued in a new research phase), applying liquid swine manure in the fall before corn (in a corn-soybean rotation) at the rate of 200 lb N/acre compared to a spring application at the same rate did not decrease corn yields or increase nitrate-N concentrations in tile drainage. Likewise, applying ammonia (in aqua form) in the fall before corn (in a corn-soybean rotation) at the rate of 150 lb N/acre compared to a spring application at the same rate did not decrease corn yields or increase nitrate-N concentrations in tile drainage. Applying ammonia in the fall before corn (in a corn-soybean rotation) at the rate of 225 lb N/acre compared to a spring application at the same rate showed a decrease corn yields but not an increase in nitrate-N concentrations in tile drainage. However, the increase in N application rate of 75 lb/ac rate (225 versus 150 for both spring and fall treatments) resulted in nitrate-N concentrations in tile drainage increasing on average from 14 to 21 mg/L, a 50% increase that was statistically significant. Although precipitation patterns were such that there was tile flow in each of the four springs of the study, only for two years was spring precipitation above normal. However, even for those years, fall applications did not increase nitrate-N leaching or decrease corn yields over spring applications. Extension work has focused on disseminating information relative to drainage water quality and economic design of drainage systems. This has included statewide, regional, and local programming events. In collaboration with colleagues at the University of Minnesota, the IA- MN Drainage Research Forum was held in November 2005 and was attended by approximately 80 stakeholders. A series of one-day drainage design workshops were held at five locations throughout Iowa in March 2006. The overall attendance was greater than 225 stakeholders. Impacts From the 225 stakeholders that attended the series of one-day drainage workshops in March 2006, a total of 125 workshop evaluations were received. Those reporting influenced drainage decisions on approximately 1.32 million acres. Participants indicated an average savings of $0.28 per acre managed and/or operated. This equates to an overall savings of approximately $369,600 and an approximate savings of $2,900 per participant for the 125 attendees that submitted evaluations. Provided summary information to the Iowa Environmental Protection Commission in February 2006 related to drainage water quality issues and specifically the impacts of various nutrient management strategies on nitrate export from tile drained lands. This information will be used in developing nutrient management strategies by the Iowa Department of Natural Resources. IL (University of Illinois) Submitted by Richard Cooke Work in continuing on the development of a showcase watershed for conducting research and demonstrations on conservation drainage practices. These practices include drainage water management systems, subsurface bioreactors, and combined bioreactor/drainage water management systems. Data are also being collected to determine the optimum sampling interval for four drainage-related best management practices. A web-based version of the Illinois Drainage Guide is up and operational. This site is designed to be a one-stop shop for drainage related information in Illinois. Innovations include interactive routines for drainage design, and a county-specific drainage simulation program that is driven by a DRAINMOD engine. Impacts A significant impact of this research is that these systems have been shown to reduce nitrates flowing from drainage tile into streams by 20 to 40 percent. This is a significant reduction in terms of environmental restoration cost and environmental benefit. IN (Purdue University) Submitted by Jane Frankenberger and Eileen Kladivko Drainage research continues at two Purdue Agricultural Centers and three private farms. Data continues to be collected for the drainage water management paired-field study, which is characterizing the effectiveness of drainage water management in reducing edge-of-field nitrate loss in subsurface tile drains on three private farms and the Davis Purdue Agriculture Center. This study is also determining co-benefits and costs of the practice with respect to soil quality attributes, crop growth, yield and fertilizer N use efficiency. Drain flow is monitored with a combination of circular flumes and insertion flow meters, and is combined with weekly nitrate sampling to determine the impacts on nitrate load using a paired watershed statistical approach. During the first year (non-growing season), the structures were open at both pairs to develop statistical relationships under equivalent management conditions. During the growing season, the outlet was raised in one field or partial field at each site, while the other field had free drainage. As in other studies, little difference in nitrate concentration has been seen between the two fields in each pair. An intensive water table study was carried out for three weeks at each site, to determine spatial patterns of water table fluctuations. Soil physical properties, earthworms, plant growth and plant N content data for each paired site have been measured to assess potential impacts on agricultural sustainability. Yields were measured with a GPS-enabled combine yield monitors, and slight yield benefits were found with drainage water management at each site in the first year. The project will continue for at least three years. Impacts The results will be used to provide recommendations to producers, drainage designers, and policy makers. Data collected will be used to enhance farmer awareness and understanding of the utility of drainage water management for providing water quality benefits. MD (University of Maryland) Submitted by Ken Staver The focus of the nearly two decade long effort to reduce N inputs from Maryland cropland into Chesapeake Bay has focused almost exclusively on reducing edge of field surface runoff losses and nitrate leaching losses from the root zone. However, repeated failures to meet nutrient reduction targets has led to a more comprehensive approach that now includes management of drainage systems to reduce the delivery efficiency of nitrate moving through subsurface flow paths. Interest in management of drainage systems has resulted from promising results from work primarily conducted in North Carolina, since only minimal data has been collected in Maryland on the impact of drainage system management on nitrate losses. However, several new projects are underway in Maryland that are dealing with the processes that control nutrient transport mechanisms in drainage systems. The longest running study is a UMD/ARS collaborative research project underway on the lower Eastern Shore in which the dynamics of nutrient transport in ditched systems in regions of intense poultry production is being studied (http://www.sawgal.umd.edu/drainageditches/). Results from this study so far suggest the potential for high levels of P transport in shallow subsurface storm flow captured in shallow surface ditches. A recently CSREES funded study is evaluating N and O isotope ratios and excess N2 gas levels in groundwater to locate zones of nitrate attenuation due to denitrification both in naturally drained systems and also where water control structures are installed. Expanded cost-share funding for water control structures is planned in Maryland and results from this study provide information on how best to manage these systems so as to maximize denitrification potential. An ongoing lysimeter study at the UMD Wye Research and Education Center is evaluating the ability of various grasses recommended for planting in riparian buffers to pull water and nitrate from shallow groundwater. Grasses became fully established in 2005 and data from 2006 should indicate the potential of various grasses once fully established down-gradient of cropland to intercept nitrate moving in subsurface flow. Impacts Success in reaching overall nutrient reduction goals set for Maryland cropland hinges on finding successful strategies for reducing subsurface N losses and dealing with concentrated nutrient sources associated with animal production. The current ongoing projects will provide information that will be useful for improving management of drainage systems so as to minimize the conveyance of nutrients lost from up-gradient cropland. The USDA/MDA collaborative effort will clarify the factors driving nutrient transport in ditched cropland associated with poultry production which will aid in the development of drainage management strategies for reducing P losses from cropland highly enriched with P. The CSREES project will provide information on the dynamics of subsurface denitrification and how water control structures can be used most effectively to attenuate nitrate leached from cropland. Findings from the UMD lysimeter study will provide information useful for selecting vegetation for riparian buffers to maximize capture of nitrate from shallow groundwater. Collectively results from these studies will be applicable in the management of nutrient losses from a major fraction of cropland in Maryland and will assist in the effort to achieve nutrient reduction goals in the Chesapeake Bay restoration effort. MI (Michigan State University) Submitted by William Northcott Pollutant Movement into Surface Drains Resulting from Liquid Manure Applications: At a Lenawee County Michigan dairy farm a field study was initiated to examine the effect of application methods and rates on the movement of liquid dairy manure movement into subsurface drains. In the Spring of 2005, twelve drainage laterals were instruments with circular drainage flumes to monitor flow and to sample drainage water. Drainage water will be sampled for NO3-, NH4+, PO4-3, fecal coliform, e. coli. and COD, Currently, only flow data and occasional samples are being taken from the site to provide background flow characteristics and pollutant concentrations. The first manure applications to the field are planned for spring 2006. The project is working jointly with Michigan USGS and NRCS. Assessing the SWAT model for application on agricultural watershed with extensive subsurface drainage: A modeling study has been in progress to assess the Soil and Water Assessment Tool for its suitability to simulate the hydrology and water quality on tile-drained watersheds. Observed data from the Vermilion River at Pontiac and the Embarras River at Camargo are being used to evaluate the performance of the model. Previous work with DRAINMOD has shown that using the Green-Ampt infiltration and Hooghoudt equations provided suitable results for tile-drained watershed. In this study we are comparing SWAT results using a daily rainfall / curve number approach and a Green-Ampt / hourly rainfall approach. Initial model results indicate that the curve number approach typically overestimates peak flow rates while the Green-Ampt method better represents peak flow rates. Initial modeling to predict nitrate loading indicates that the SWAT model is doing a poor job of predicting nitrate concentrations. This is mostly likely due to the nitrate algorithm in SWAT assumes nitrate loading via surface runoff rather than through subsurface drains. Impacts Over 2000 dairy farms in the state of Michigan applied manure to fields, a large percentage of them being subsurface drained. It is important to develop manure application practices and strategies that minimize the movement of pollutants associated with manure into subsurface drains and eventually into surface waters. MN (University of Minnesota) Submitted by Jeff Strock and Gary Sands Drainage research continues both at University of Minnesota Research and Outreach Centers (ROC) and on cooperating farms. Eight to 10 faculty at the University of Minnesota and several State agencies are engaged in numerous projects addressing hydrology, water quality and production impacts of subsurface drainage practices. These projects encompass a multitude of scales, (plot to large watershed), and approaches (field, laboratory and computer modeling). Current research topics include (but are not limited to): scavenger crops for minimizing nitrate-N losses; shallow and controlled drainage for minimizing nitrate-N losses; pharmaceutical movement and antibiotic resistance in drained soils; ecological approaches to drainage ditch design/management for water quality; impacts of combinations of alternative drainage and other conservation practices; preferential flow theory and modeling, and; modeling soil responses to drainage. Field research at the Southern ROC is investigating the role of drainage depth and spacing on hydrology and nitrate-nitrogen losses from drained lands. Five years of data beginning in 2001 indicates that shallow drainage can reduce seasonal drainage volumes and nitrate-nitrogen by 18 percent over a 5-year period. This research also shows that drain spacing has a similar effect on nitrate-nitrogen losses. When drain spacings designed for a 13 mm/day design drainage rate (intensity) were cut in half (resulting in a 51 mm/d drainage intensity), 5-year nitrate-nitrogen loads 17 percent. Installation of several on-farm controlled drainage research/demonstration sites is being conducted in southern Minnesota. Drainage volumes and nitrate-nitrogen losses will be measured at these sites, in addition to crop yield and soil quality parameters. Two literature reviews are underway with scheduled completion in 2006: (1) water quality impacts of water table management systems, and (2) impacts of subsurface drainage on aquatic ecosystems. Drainage and water resource management research at the Southwest Research and Outreach Center (SWROC) is being conducted at plot, field, and small watershed scales. Research may be grouped into three theme areas: those related to in-field, edge-of field, and in-stream practices and management systems to reduce contaminant losses from agricultural lands to surface and ground water. Research continued in the area of evaluating soil N testing procedures, based on the soils nitrogen supplying capacity, to reduce or redistribute N inputs within a field and minimize N losses. Research on doublecrop small grain-snap bean in rotation with soybean to achieve agronomic, economic, and environmental goals was also continued. A field site was established to investigate the effect of controlled drainage on water quality and quantity, crop yield, soil physical and chemical properties, and greenhouse gas emissions. A project was initiated to measure the effectiveness and efficiency of agricultural contaminant removal from by constructed treatment wetlands designed to improve water quality. Research continued at two scales on evaluating controls of nitrogen and phosphorus transfers from agricultural soils to open-channel ditches and from open-channel ditches to receiving waters. Research also continued on evaluation of ditch management strategies to reduce nitrogen and phosphorus loading from agricultural runoff in small watersheds. MN (USDA-ARS) Submitted by Tyson Ochsner In 2005 we established a new paired subsurface drainage system experiment. This field scale, on-farm experiment is part of a larger effort to document the environmental impact of large dairy operations, the number of which is increasing in the Midwest. The paired drainage system experiment will be used to determine the water quality impacts of changes in crop rotation and nutrient management which are necessitated by these dairies. The treatment field will be placed into a corn-corn-soybean rotation and will receive injected dairy manure after the soybean. The control field will remain in corn-soybean rotation with synthetic N fertilizer applied following the soybean. Water flow and nutrient concentrations in the subsurface drainage systems were measured in 2005. This calibration period data will permit statistical tests for changes caused by the treatment. Additional calibration data will be collected through soybean harvest in 2006, after which the treatment will be applied. Impacts As a result of this on-farm experiment, several area farmers have extended invitations for research work on their land. The operators of several new large dairies in the area have also expressed interest in collaborating with the overall research project. MO (University of Missouri) Submitted by Kelly Nelson Drainage and subirrigation research in Northeast Missouri was continued. Polymer coated and non-coated urea research was completed in 2005. A drainage design workshop was held at Macon, MO in February, 2006 with over 50 attendees. Polymer coated urea improved nitrogen utilization and grain yields when compared to non-coated depending on drainage and irrigation intensity. Movement of nitrogen into the subsoil and nitrous oxide gas release was evaluated on different drainage and irrigation intensities. Water table management using subirrigation has increased corn and soybean grain yields 38 and 25%, respectively. Drainage has increased corn and soybean grain yields 17 and 20%, respectively. Overhead irrigation increased grain yield 20% compared to subirrigated corn with 20 ft laterals when averaged over all N treatments in 2004 and 2005. However, applied water was 10 times greater for overhead irrigated corn compared with subirrigated corn during this period. NC (North Carolina State University) Submitted by R. Wayne Skaggs, Mohamed A. Youssef and Robert O. Evans A collaborative study has been started to test DRAINMOD-N II using a data set from Germany. The data set consists of twelve years of drainage and water quality data, collected from a drained grassland site receiving both mineral N fertilizers and animal waste. The testing has not been completed yet, but preliminary results indicated that DRAINMOD-N II can be used in simulating N dynamics in grasslands. Results also highlighted the need of the model, which was developed for agricultural systems, to a plant/vegetation component that simulates grass growth as affected by weather conditions, availability of water and nutrients, and grazing. Another Field testing of DRAINMOD-N II for the conditions of the US Midwest has been started using an 8-yr data set from a Minnesota field experiment that was conducted on a subsurface drained Canisteo clay loam planted to a corn soybean rotation to study the effect of the time of application of N fertilizer and the use of the nitrification inhibitor, Nitrapyrin, on N drainage losses. The data set was compiled and rearranged to be in a form suitable for model testing. Hydrologic and nitrogen model input files were prepared. A two-step global sensitivity analysis was conducted for DRAINMOD-N II using the LH-OAT and the extended FAST techniques to assess the sensitivity of model predictions of N losses from drained croplands to various model inputs. Results of this study indicated that the model is most sensitive to denitrification parameters and is mildly sensitive to parameters controlling decomposition of organic matter. Results of this study should help potential users of the model make informed decisions about model parameterization. A software company was contracted to upgrade the Windows interface of DRAINMOD and to incorporate DRAINMOD-N II in the Windows-based DRAINMOD suite of models. The new shell is currently being tested and shortly will be released to users. SD (South Dakota State University) Submitted by Todd Trooien and Hal Werner Two models are being tested with runoff, drain flow, and hydraulic gradient data from a drained waterway site. The models are a water balance model developed at SDSU for drained waterways and DRAINMOD adapted to single-drain (as opposed to pattern-drained) waterways. Two graduate students are in the final stages of testing and preparing their theses. Preliminary results indicate (1) the addition of artificial drainage to a waterway can decrease runoff and the related contaminant issues such as phosphorus, (2) the addition of artificial drainage increases the long-term average corn yield in a cropped waterway, and (3) DRAINMOD can adequately simulate a drained waterway by using an effective drain spacing. Impacts Our results indicate a slight yield advantage to adding artificial drainage to cropped waterways. A producer can evaluate the economics of adding such drainage in addition to the benefits that are harder to quantify: timeliness of field operations, reduced runoff, etc.

Allred, B.J., Fausey, N.R., Daniels, J.J., Chen, C., Peters, L., Youn, H. 2005. Important considerations for locating buried agricultural drainage pipe using ground penetrating radar. Applied Engineering in Agriculture. 21(1):71-87. Allred, B.J., Redman, D., Mccoy, E.L. 2005. Golf course applications of nearsurface geophysical methods. Journal of Environmental & Engineering Geophysics. 10(1):1-19. Bakhsh, A. and R.S. Kanwar. 2005. Mapping Clusters of NO3-N Leaching Losses with Subsurface Drainage Water. Journal of American Water Resources Association 41(2):333-341. Bakhsh, A., R.S. Kanwar, and D. Karlen. 2005. Effects of liquid swine manure applications on NO3-N -N leaching losses to subsurface drainage water. Agriculture, Ecosystems and Environment 109(1-2):118-128. Bakhsh, A., R.S. Kanwar, and D. Karlen. 2005. Effects of liquid swine manure applications on NO3-N leaching losses to subsurface drainage water. Agriculture, Ecosystems and Environment 109(1-2):118-128. Bakhsh, A., R.S. Kanwar, D. B. Jaynes, T. S. Colvin and L. R. Ahuja. 2005. Modeling precision agriculture for better crop productivity and environmental quality. International Agricultural Engineering Journal 14(4):1-10. Burchell, M.R. II, R.W. Skaggs, G.M. Chescheir, J.W. Gilliam and L.A. Arnold. 2005. Shallow subsurface drains to reduce nitrate losses from drained agricultural lands. Trans. ASAE 48(3):1079-1089. Daniels, J.J., Allred, B.J., Binley, A., Labrecque, D., Alumbaugh, D. 2005. Hydrogeophysical case studies in the vadose zone. In: Rubin, Y., Hubbard, S., editors. Hydrogeophysics. New York, NY: Springer. p. 413-440. Du, B., J.G. Arnold, A. Saleh, and D.B. Jaynes. 2005. Development and application of SWAT to landscapes with tiles and potholes. Trans ASAE 48:1121-1133. Fernandez, G.P., G.M. Chescheir, R.W. Skaggs and D.M. Amatya. 2005. Development and testing of watershed scale models for poorly drained soils. Trans. ASAE 48(2):639-652. Huynh, L., Vantoai, T.T., Streeter, J., Banowetz, G.M. 2005. Regulation of flooding tolerance of sag12:ipt arabidopsis plants by cytokinin. Journal of Experimental Botany. Vol. 56, No. 415, pp. 1297-1407. Kanwar, R.S., R. Cruse, M. Ghaffarzadeh, A. Bakhsh, D. Karlen, and T. Bailey. 2005. Corn-soybean and alternate farming systems effects on water quality. Applied Engineering in Agriculture 21(2):181-188. Kladivko, E.J., G.L Willoughby, and J.B. Santini. 2005. Corn growth and yield response to subsurface drain spacing on Clermont silt loam soil. Agron. J. 97:1419-1428. Kung, K.-J.S., M. Hanke, C.S. Helling, E.J. Kladivko, T.J. Gish, T.S. Steenhuis, and D.B. Jaynes. 2005. Quantifying pore-size spectrum of macropore-type preferential pathways. Soil Sci. Soc. Am. J. 69:1196-1208. Lander, K, P.K. Kalita, and R.A. Cooke. 2005. Base flow characteristics of a subsurface drained watershed. Intl. Agric. Eng. Journal, Vol. 14(4), 171-179. Sammons, R.J., R.H. Mohtar, W.J. Northcott. 2005. Modeling Subsurface Drainage Flow of a Small, Tile-Drained Watershed Using DRAINMOD. Applied Engineering in Agriculture. American Society of Agricultural Engineers. Vol. 21(5): 815-834. Shelby, J.D., G.M. Chescheir, R.W. Skaggs and D.M. Amatya. 2005. Hydrologic and water-quality response of forested and agricultural lands during the 1999 extreme weather conditions in eastern North Carolina. Trans. ASABE 48(6): 2179-2188. Skaggs, R.W., G.M. Chescheir and B.D. Phillips. 2005. Methods to determine lateral effect of a drainage ditch on wetland hydrology. Trans. ASAE, 48(2):577-584. Skaggs, R.W., M.A. Youssef, G.M. Chescheir and J.W. Gilliam. 2005. Effect of drainage intensity on nitrogen losses from drained lands. Transactions of the ASABE 48(6):2169-2177. Strock, J.S., D. Bruening, J.D. Apland, D.J. Mulla. 2005. Farm management practices in two geographically diverse watersheds in the Cottonwood River Watershed of Minnesota. Water, Air, and Soil Pollution. 165:211-231 Strock, J.S., G.R. Sands, D. Deutsch, and C. C. Surprenant. 2005. Design and testing of a paired drainage channel research facility. Appl. Eng. Agric. 21:63-69. Strock, J.S., M.A. Schmitt. 2005. Manure nitrogen management for corn on loess soil in a sensitive groundwater area. [Online]. Crop Management. http://www.plantmanagementnetwork.org/sub/cm/research/2005/water/ Thoma, D.P., S.C. Gupta, J.S. Strock, and J.F. Moncrief. 2005. Tillage and nutrient source impacts on water quality from a flat landscape. J. Environ. Qual. 34:1102-1111. Torbert III, H.A., King, K.W., Harmel, R.D. 2005. Impact of soil amendments on reducing p losses from runoff in sod. Journal of Environmental Quality. 34:1415-1421. Wang, X., M.A. Youssef, R.W. Skaggs, J.D. Atwood, and J.R. Frankenberger. 2005. Sensitivity analysis of the nitrogen simulation model, DRAINMOD-NII. Trans. ASABE 48(6):2205-2212. Youssef, M.A., R.W. Skaggs, G.M. Chescheir, and J.W. Gilliam. 2005. The nitrogen simulation mode, DRAINMOD-NII. Trans ASAE, 48(2): 611-626. Zhu, H., Krause, C.R., Zondag, R.H., Brazee, R.D., Derksen, R.C., Reding, M.E., Fausey, N.R. 2005. A new system to monitor water and nutrient use efficiency in pot-in-pot nursery production system. Journal of Environmental Horticulture. 23(1):47-53. Extension or Non-refereed Publications for 2005 Algoazany, A,. P. K. Kalita, J. K. Mitchell, R. A. Cooke. 2005. A long-Term Monitoring of Agricultural Chemical Transport From A Flat Tile-Drained Watershed. ASAE International Meeting, ASAE Paper # 05-2255. St Joseph, MI. Bakhsh, A. and R.S. Kanwar. 2005. Landscape attributes effects on NO3-N leaching losses to subsurface drainage water. In: Proceedings of the International Agricultural Engineering Conference, December 6-9, 2005, Bangkok, Thailand. Brouder, S., B. Hofmann, E. Kladivko, R. Turco, A. Bongen, and J. Frankenberger. 2005. Interpreting nitrate concentration in tile drainage water. Purdue Extension Publ. AY-308-W. http://www.ces.purdue.edu/extmedia/AY/AY-318-W.pdf. Cooke, R.A., G.R. Sands and L.C. Brown. 2005. Drainage water management: A Practice for reducing nitrate loads from subsurface drainage systems. Upper Mississippi River Hypoxia Conference. Ames, Iowa, September 2005. Du, .B., Saleh, A., Jaynes, D.B., Arnold, J.G. 2005. Evaluation of SWAT in simulating atrazine losses in stream discharge for Walnut Creek watershed (Iowa) [CD-ROM]. Watershed Management Conference Proceedings. Atlanta, Georgia. Feyereisen, G.W. 2005. A Probabilistic Assessment of the Potential for Winter Cereal Rye to Reduce Field Nitrate-Nitrogen Loss in Southwestern Minnesota. Ph.D. dissertation. University of Minnesota, St. Paul, Minn. Frankenberger, J., E. Kladivko, B. Gutwein, R. Adeuya, L. Bowling, B. Carter, S. Brouder, J. Lowenberg-DeBoer, and J. Brown, 2005. On-farm monitoring to assess the impacts of drainage water management. ASAE Paper No. 052027. St. Joseph, Mich.: ASAE. Goswami, D., P. K. Kalita, R. A. Cooke. 2005. Estimation of Base Flow in Drainage Channels in Two Tile Drained Watersheds in Illinois. ASAE International Meeting, ASAE Paper # 05-2066. St Joseph, MI. Helmers, M. J. and P. A. Lawlor. 2005. Conservation systems: Effects of manure application on drainage water quality. In Proceedings of the 17th Annual Integrated Crop Management Conference (November 30 and December 1, 2005, Iowa State University, Ames, IA), pp. 177-188. Helmers, M. J., P. A. Lawlor, J. L. Baker, S. W. Melvin, and D. W. Lemke. 2005. Temporal subsurface flow patterns from fifteen years in north-central Iowa. ASAE Meeting Paper No. 05-2234. St. Joseph, MI: ASAE. Lawlor, P. A., M. J. Helmers, J. L. Baker, S. W. Melvin, and D. W. Lemke. 2005. Nitrogen application rate effects on corn yield and nitrate-nitrogen concentration and loss in subsurface drainage. ASAE Meeting Paper No. 05-2025. St. Joseph, MI: ASAE. Miller, N.C. 2005. Grade control capability of cantilever drainage plows under experimental conditions. Ohio State University Thesis. Nelson, K., R. Smoot, and M. Jones. 2005. MU Drainage and Subirrigation (MUDS) Research Update. http://aes.missouri.edu/greenley/research/muds.stm. Rengsang, P., R.S. Kanwar, M. Jha, P.W. Gassman, K. Ahmad, and A. Saleh. 2005. Assessment of agricultural management practices in the Upper Maquoketa River Watershed. In: Proceedings of the 3rd International SWAT Conference (Editors: R. Srinivasan, J. Jacob, D. Day, and K. Abbaspur), July 13-15, 2005, EAWAG, Zurich, E.T.H. Switzerland. Singh, A K, L Blankers, J K Oswald, T P Trooien, and H D Werner. 2005. Accuracy, precision, and sensitivity of ultrasonic sensors to measure the water level in piezometers. ASAE Paper SD05-400. ASAE: St Joseph, MI. Strock, J.S., M.A. Schmitt. 2005. Manure nitrogen management for corn on loess soil in a sensitive groundwater area. [Online]. Crop Management. http://www.plantmanagementnetwork.org/sub/cm/research/2005/water/ Wortman, C. S., M. J. Helmers, A. Mallarino, C. Barden, D. Devlin, G. Pierzynski, J. Lory, R. Massey, J. Holz, C. Shapiro, and J. Kovar. 2005. Agricultural phosphorus management and water quality protection in the Midwest. RP187 Heartland Regional Water Coordination Initiative. Iowa State University Extension.