Source: NORTH DAKOTA STATE UNIV submitted to
IMPACT OF SUBSURFACE DRAINAGE ON WATER AVAILABILITY IN THE RED RIVER BASIN
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0214581
Grant No.
2008-35102-19253
Project No.
ND05047
Proposal No.
2008-01754
Multistate No.
(N/A)
Program Code
26.0
Project Start Date
Sep 1, 2008
Project End Date
Aug 31, 2011
Grant Year
2008
Project Director
Jia, X.
Recipient Organization
NORTH DAKOTA STATE UNIV
(N/A)
FARGO,ND 58105
Performing Department
CIVIL, AGRICULTURAL, & GEOLOGICAL ENGINEERING
Non Technical Summary
A wet weather cycle in the Red River Basin region since 1993 has brought the ground water level closer to the soil surface in many areas. Subsurface drainage (SSD) can be an effective way to maintain crop production where shallow groundwater exists over a poorly drained soil or where soil salinity has elevated due to higher water tables. However, releasing drainage water into the Red River modifies the water balance and water quality (water availability), which, in turn, may disrupt the existing ecology and hydrological balance of the regional watershed and wetlands. Through this seed grant, we plan to use an existing test field to (1) conduct comprehensive measurements of the water mass balances of drained and undrained fields, with emphases on validation of evapotranspiration ET estimates by satellite-based remote sensing energy balance model using a suite of ground-based measurements, including eddy correlation, scintillometer, and soil water balance methods, and on their inter-comparison; (2) develop remote sensing algorithms for identifying fields with SSD installed; and (3) extend results from this seed grant project to a larger spatial scale, watershed or regional, preferably through a standard USDA NRI proposal. This study and potentially the future one are well aligned with one of the two USDA NRI Water/Watershed program's priorities - to identify, evaluate, and understand SSD that improves agricultural water conservation and crop production.
Animal Health Component
60%
Research Effort Categories
Basic
20%
Applied
60%
Developmental
20%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
4050210202080%
4040210205020%
Goals / Objectives
(1) To conduct comprehensive water mass balance measurements of drained and undrained fields, with emphases on validation of evapotranspiration estimates by satellite-based remote sensing energy balance model, using ground-based measurements by eddy correlation, scintillometer, and soil moisture sensors, and their inter-comparison. (2) To develop remote sensing algorithms for identifying fields with subsurface drainage installed. (3) To extend results gained from this seed grant project over a larger spatial scale, watershed or regional, through a standard USDA NRI proposal.
Project Methods
The project will compare the evapotranspiration (ET) between a subsurface drained and an undrained field at a test site, located at Fairmount, Richland county, North Dakota. The test field has an area of 47 ha, of which 27 ha are undrained and 20 ha are drained. A subsurface drainage system was installed in August 2002. The drainage pipes are located from 0.9 to 1.5 m depth, with 18 m spacing. The overall drainage flows from west to east into a main on the east side of the field. The drainage water is pumped to a county ditch located near the northeast corner of the field. ET will be measured by a remote sensing energy balance method as well as ground based water mass balance and micrometeorological methods. For the water mass balance method, two types of soil moisture sensors, neutron probe and Hydra Probe II, will be used in both fields. The arrangement of dual sensors of neutron probe and hydra probe has been shown to be the most accurate method for mapping soil moisture dynamics vertically and horizontally. One eddy correlation system will be installed in the drained portion of the field and one in the undrained portion of the field during the growing season. Solar radiation, wind speed, air temperature, and relative humidity measurements will be collected at 30 min intervals to provide ground-based weather data for ET estimation. A scintillometer will be used during a brief intensive operating period. It will be deployed in an east-west direction across the eddy correlation system to collect sensible heat flux data. These data will be used to verify the eddy correlation measurements and the components of the energy balance model. For both years, the satellite images from ASTER and Landsat during the growing season will be used with the energy balance model to calculate the ET for each field during the experimental period. Both Landsat and ASTER have a revisit frequency of 16 days, but cloud cover may affect data availability. In case of lengthy cloudiness, an airborne multispectral sensor, AeroCam, operated by the University of North Dakota, will be requested to take images, which have nominal ground pixel sizes of 0.5 to 2 meters. Satellite images will be atmospherically corrected. We will also validate satellite observation by measuring spectral reflectance in the field using an ASD hyperspectral radiometer twice per year. When matching surface reflectance data, the satellite data will be calibrated using the surface measurements. For comparison with the flux tower and the scintillometer measurements, we will analyze the variations of footprints for these field instruments. Satellite-based energy balance for ET will be estimated and calibrated using eddy correlation, scintillometry, and soil water balance methods. Critical temporal differences in ET and potentially, spatial statistics describing ET variations within fields can be evaluated. Establishing a water balance within the two fields will provide a first look at the potential for identifying the impacts of drainage water quantity and quality on the Red River.

Progress 09/01/08 to 08/31/11

Outputs
OUTPUTS: Activities: We have accomplished our goals and completed all field experiments in fall 2010. Data analysis and publications were mainly conducted during this duration. Four M.S. students thesis have been completed from fall 2010 to summer 2011. Events: The project results were presented in one national conference, one regional conference, three state conferences, one mini-symposium on Red River Valley tile drainage, and one field tour on drainage. Services: The research team has been providing free consulting service to the Red River Basin Flood Retention authority and the Red River Basin Technical and Scientific Advisory Committee on whether, when, and how subsurface drainage impact on Red River Flood. Products: The major product from this project is the quantification of the water balance (particularly the evapotranspiration) between the subsurface drained and undrained crop fields, which have been used to calculate the soil water storage for flood retention, and verify popular drainage models. One new course on Drainage Engineering, ABEN 484/684, was developed based on the knowledge gained through this project. The PD and Co-PDs also teach four courses related to drainage topics. One landowner in Clay County, MN has established a new controlled drainage and subirrigation project. Six graduate students, one undergraduate student, five technical staff members, and five faculty members were trained from this project. PARTICIPANTS: Individuals: Xinhua Jia at the Department of Agricultural and Biosystems Engineering of North Dakota State University acts as the PD of the project and oversee the entire project. Her responsibilities included recruitment of two graduate students, equipment purchase, lab and field experiments (sensor calibration, programming and weather station setup), data analysis (data quality control and calculation), budget monitoring, presentations at state, regional and national conferences, and publications. She is also providing project deliverables, such as annual report. She has also collaborated with other collaborators associated with the project. Dean Steele and his full time technician, Shelton Tuscherer, also at the Department of Agricultural and Biosystems Engineering of North Dakota State University have been working on some of the field experiments, such as data collection, data analysis, and soil moisture measurements. Dean Steele is also coauthoring on the publications. Xiaodong Zhang at the Department of Earth System Science & Policy of University of North Dakota has been in charge of estimating evapotranspiration rate using the scintillometers and remote sensing. He also has one student working on the scintillometer ET measurement and another working on development of remote sensing algorithm for SSD mapping. Partner organizations: North Dakota State University, University of North Dakota, ND State Water Commission, ND Department of Health, NRCS, and ND Water Resources Research Institute. Collaborators and contacts: Thomas F. Scherer: Associate Professor of Agricultural and Biosystems Engineering Roxanne Johnson: Water Quality Associate of Agricultural and Biosystems Engineering Thomas M. DeSutter: Assistant Professor of Soil Science David Hopkins: Associate Professor of Soil Science Hans Kandel, Assistant Professor of Plant Science Department Bill Schuh: Soil Scientist of ND State Water Commission, Bismarck, ND Michael Sauer: water quality specialist of ND Department of Health, Bismarck, ND Steve Fisher: coordinator of Lake Agassiz RC&D, Fargo, ND Gary Sands: Associate Professor of Biological Systems Engineering Department, University of Minnesota, St. Paul, MN Training: Graduate students: Xiao Pang, Ishara Rijal, Junyu Yang, and Santosh Rijal. Farmers: besides Steven Miller and Mike Freeberg at the Miller's farm, we also reached several hundreds of farmers through MN-ND drainage forums, tile drainage field day, and meetings. TARGET AUDIENCES: This project provides an opportunity for farmers, university students, state agencies, and professional communities to understand better on where the water goes and its environmental impact to the surface water system. Approaches are through a formal classroom instruction to 40 students, development of a new course on drainage engineering, and education people via forums, invited talks, and field days. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
This project has compared water availability between a tile drained and undrained fields using ground measured and remotely-sensed satellite data. The satellite extracted soil moisture data can determine the drained and undrained fields during spring time. A remote sensing algorithm based on soil reflectance at different moisture levels was developed to identify tile drained fields. The developed algorithm was also verified in other areas. The ground measured water balance data has been used to determine the impact of subsurface drainage on flood retention and application of popular drainage models, such as DrainMod, Hydrus 2D, SWAT, and GSSHA. The immediate outcome from this project has benefited the cooperating landowner who was involved in this project. Due to a better understanding of the water balance, he has learned how to use the water level and soil moisture data to guide his conservation drainage process. Water quality in the surface water has also been improved due to decrease of drainage water into the surface water system. For the research team, we were able to use sensors to guide the conservation drainage process, and a new method was developed to measure the drainage outflow through this project. A remote sensing algorithm based on soil reflectance at different moisture level was developed to identify subsurface drained fields. The research results were shared with the public and other research groups for drainage model applications. The research team has gained more knowledge about impact of subsurface drainage on the Red River Flood from the water balance point of view. A new research project on controlled drainage and subirrigation has been started. It is expected that more farmers and public will adopt the technology for a better nutrient management plan incorporated in the water management plan. The results from this project will affect the Red River Valley area and anywhere where subsurface drainage is practiced.

Publications

  • Jia, X., DeSutter, T. M., Lin, Z., Schuh, W.B., and Steele, D.D. (2011). Controlled drainage and subirrigation effects on water quality in southeast North Dakota. Agricultural Water Management. Pending.
  • Rijal, I., Jia, X., Zhang, X., Steele, D. D., Scherer, T. F., and Akyuz, A. (2011). Evapotranspiration measurement and crop coefficient development for corn and soybean in surface and subsurface drainage condition. J. of Irrigation and Drainage. Pending.
  • Jia, X., Scherer, T. F., DeSutter, T. M., Lin, Z., and Steele, D. D. (2011). Controlled drainage and subirrigation effect on crop production and water quality. Eastern South Dakota Water Conference. October 13, 2011, Brookings, SD.
  • Jia, X., Akyuz, A. and Lin, D. (2011). Predict soil freeze and thaw cycle and maximal frost depth in the Red River Valley. 2011 ASABE Annual International Meeting. August 7-10, 2011, Louisville, KY.


Progress 09/01/09 to 08/31/10

Outputs
OUTPUTS: IMPACT OF SUBSURFACE DRAINAGE ON WATER AVAILABILITY IN THE RED RIVER BASIN. Field experiment continued in the 2010 growing season at Fairmount, ND. Major water balance components, including precipitation, evapotranspiration, drainage and irrigation amounts, and soil moisture changes were measured directly in the subsurface drainage and undrained fields. Surface reflectance and soil moisture content at 15 cm depth were also measured when the soil surface was not covered by vegetation, and a remote sensing algorithm was developed to map the soil moisture difference in a large scale. Data analysis has been completed and four M.S. students thesis have been completed or about to finish. The major output from this project is the quantification of the water balance between the drained and undrained fields. Four conference presentations, two peer reviewed publications, and one field day have been conducted to share the project results to the public. A new course on Drainage Engineering, ABEN 484/684, has been developed based on the knowledge gained through this project. Dr. Xinhua Jia has been teaching this course in fall 2010. Through the ND Drainage Forum in February 2010, the research team was able to talk about the Fairmount Drainage project to about 150-200 people, including farmers, contractors, federal agency personals, etc. Several farmers contacted the research team about their questions related to drainage, and several state and local agencies reached the research team about their input on tile drainage impact on Red River Flood and retention. One farmer in Glyndon, MN contacted the research team for a new controlled drainage and subirrigation project. The drainage system and controlled drainage structures were installed in fall 2010 and a proposal was submitted to an appropriate agency for future funding. This project is conducted by North Dakota State University and the University of North Dakota, and additional funding and service were provided by several state agencies, including ND State Water Commission and ND Department of Health. A strong collaboration and networks have been fostered by the project. PARTICIPANTS: Individuals: Xinhua Jia at the Department of Agricultural and Biosystems Engineering of North Dakota State University acts as the PD of the project and oversee the whole project. Her responsibilities include that recruitment of two graduate students, equipment purchase, lab and field experiments (sensors calibration, programming and weather station setup), data analysis (data quality control and calculation), budget monitoring, presentations at state, regional and national conferences, and publications. She is also providing project deliverables, such as annual report. She has also collaborated with other collaborators associated with the project. Dean Steele and his full time technician, Shelton Tuscherer, also at the Department of Agricultural and Biosystems Engineering of North Dakota State University have been working on some of the field experiments, such as data collection, data analysis, and soil moisture measurements. Dean Steele is also coauthoring on the publications. Xiaodong Zhang at the Department of Earth System Science & Policy of University of North Dakota has been in charge of estimating evapotranspiration rate using the scintillometers and remote sensing. He also has one student working on the scintillometer ET measurement and another working on development of remote sensing algorithm for SSD mapping. Partner organizations: North Dakota State University, University of North Dakota, ND State Water Commission, ND Department of Health, and NRCS. Collaborators and contacts: Thomas F. Scherer: Associate Professor of Agricultural and Biosystems Engineering Roxanne Johnson: Water Quality Associate of Agricultural and Biosystems Engineering Thomas M. DeSutter: Assistant Professor of Soil Science David Hopkins: Associate Professor of Soil Science Frank Casey: Associate Professor of Soil Science Hans Kandel, Assistant Professor of Plant Science Department Bill Schuh: Soil Scientist of ND State Water Commission, Bismarck, ND Steve Miller: collaborator, Fairmount, Richland County, ND Michael Sauer: water quality specialist of ND Department of Health, Bismarck, ND Steve Fisher: coordinator of Lake Agassiz RC&D, Fargo, ND Gary Sands: Associate Professor of Biological Systems Engineering Department, University of Minnesota, St. Paul, MN Training: Graduate students: Xiao Pang, Ishara Rijal, Junyu Yang, and Santosh Rijal. Farmers: besides Steven Miller and Mike Freeberg at the Miller's farm, we also reached several hundreds of farmers through MN-ND drainage forums, tile drainage field day, and meetings. TARGET AUDIENCES: This project provides an opportunity for farmers, university students, state agencies, and professional communities to understand better on where the water goes and its environmental impact to the surface water system. Approaches are through a formal classroom instruction to 40 students, development of a new course on drainage engineering, and education people via forums, invited talks, and field days. PROJECT MODIFICATIONS: NO

Impacts
This project has compared the water availability (water balance and water quality) between a tile drained and undrained fields. The immediate outcome from this project has benefited the cooperative farmer who is involved in this project. Due to a better understanding of the water balance, he has learned how to use the water level and soil moisture change in the field to guide his conservation drainage process. He has become aware of using the sump pump to control drainage at a timely and precisely manner to conserve water for a higher crop yield. The water quality in the surface water has also been improved due to the time change of fertilizer application from fall to spring and reduced drainage water and nutrient amount from the field. The cooperative farmer stopped the sump pump for drainage on June 27, 2008, June 3, 2009, and May 24, 2010, so that less amount water and nutrient were left the field to the surface water system. For the research team, we were able to use sensors to guide the process, and a new method was developed to measure the drainage effluent through this project. The drainage conservation techniques developed from this project has been shared with the public and used by other farmers in the Red River Valley (RRV) region. A significant policy change has been enforced in ND and drainage permit is now required for new tile drainage installation. The research team has gained more knowledge about the impact of tile drainage on the Red River Flood from the water balance point of view. New research project on snow hydrology has been started. It is expected that more farmers and public will adopt the technology for a better nutrient management plan incorporated in the water management plan. The results from this project will affect the RRV area and anywhere drainage is practiced.

Publications

  • Zhang, X., X. Jia, J. Yang, and L. Hu. 2010. Comparison of sensible heat flux measured by eddy-covariance and large aperture scintillometer over a corn field with subsurface drainage. Journal of Agricultural and Forest Meteorology. 150:1182-1191.
  • Scherer, T.F., and Jia, X. 2010. A simple method to measure the flow rate and volume from tile drainage pump stations. Applied Engineering in Agriculture. 26(1):79-83.
  • DeSutter, T., and X. Jia. 2010. Report to the North Dakota Department of Health for project: Tile drainage and subirrigation evaluation in Richland County for effects on soil and water quality. ND Department of Health, Bismarck, ND.
  • Rijal, I., X. Jia, D. D. Steele, T. Scherer, X. Zhang, and X. Pang. 2010. Comparison of reference and actual evapotranspiration in North Dakota (ND). ASABE 2010 Annual International Meeting, June 20-23, 2010, Pittsburgh, PA.
  • Pang, X., X. Jia, T. M. DeSutter, T. F. Scherer, D. D. Steele, and I. Rijal. 2010. Effect of subsurface drainage on water availability in the Red River Valley of the North. ASABE 2010 Annual International Meeting, June 20-23, 2010, Pittsburgh, PA.
  • Jia, X., X. Zhang, and D. D. Steele. 2010. Impact of subsurface drainage on water availability in the Red River Basin. February 22, 2010. USDA National Water Conference, Hilton Head, SC.
  • Jia, X., and T. DeSutter. 2010. Fairmount tile drainage research update. ND-MN Drainage Forum, February 2, 2010, Fargo, ND.
  • Jia, X. 2009. Where does the water go WISMET, December 7, 2009, Fargo, ND.
  • Jia, X. 2009. Tile drainage/subirrigation research in Richland County. North Dakota Soil Water Conservation Society Annual Meeting, October 15-16, 2009, Fargo, ND.
  • Jia, X. 2009. Water balance for drained and subirrigated corn. ADMS semiannual conference, October 13-14, Minneapolis, MN.
  • Rijal, I., X. Pang, and X. Jia. 2009. Soil moisture distributions for subsurface drainage and subirrigation soils. 2009 ASABE/CSBE North Central Intersectional Conference, September 18-19, 2009. Brookings, SD.


Progress 09/01/08 to 08/31/09

Outputs
OUTPUTS: An experimental field was chosen to evaluate the water balance and water quality differences between the undrained and subsurface drained (SSD) fields. Accurate evapotranspiration (ET) measurement is the key to quantify the water balance. During this study period, corn ET was measured using eddy correlation, soil water balance, and scintillometry methods on the ground. The ET results will be used to calibrate and validate remote sensing developed ET model. Two 3.4 m wide permanent alleys were installed across the field so that all instruments can be installed without interference farmer's field activities. Twenty-four piezometers were installed across the field in the undrained and SSD fields. Automatic water level sensors were installed to record water level changes in every 30-min interval. These piezometers were also used to collect water samples at a biweekly schedule. Cations, anions, nutrient, and trace metals were analyzed by the ND Department of Health lab. Neutron probe and hydra probe II soil moisture sensors were used to measure soil moisture continuously over time or through a soil profile. The outflow from the SSD was measured by a current sensor and an automatic water level sensor. Rainfall was recorded using both automatic and manual standard rain gages. Four graduate students are mentored through this project. A tile drainage field day through the North Dakota State Water Commission was held on June 16, 2009 and visited the experimental site. PARTICIPANTS: Individuals: Xinhua Jia at the Department of Agricultural and Biosystems Engineering of North Dakota State University acts as the PD of the project and oversee the whole project. Her responsibilities include that recruitment of two graduate students, equipment purchase, lab and field experiments (sensors calibration, programming and weather station setup), data analysis (data quality control and calculation), budget monitoring, presentations at state, regional and national conferences, and publications. She is also providing project deliverables, such as annual report. She has also collaborated with other collaborators associated with the project. Dean Steele and his full time technician, Shelton Tuscherer, also at the Department of Agricultural and Biosystems Engineering of North Dakota State University have been working on some of the field experiments, such as data collection, data analysis, and soil moisture measurements. Dean Steele is also coauthoring on the publications. Xiaodong Zhang at the Department of Earth System Science & Policy of University of North Dakota has been in charge of estimating evapotranspiration rate using the scintillometers and remote sensing. He also has one student working on the scintillometer ET measurement and another working on development of remote sensing algorithm for SSD mapping. Partner organizations: North Dakota State University, University of North Dakota, ND State Water Commission, ND Department of Health, and NRCS. Collaborators and contacts: Thomas F. Scherer: Associate Professor of Agricultural and Biosystems Engineering at NDSU. Roxanne Johnson: Water Quality Associate of Agricultural and Biosystems Engineering at NDSU. Thomas DeSutter: Assistant Professor of Soil Science at NDSU. David Hopkins: Associate Professor of Soil Science at NDSU. Frank Casey: Associate Professor of Soil Science at NDSU. Hans Kandel, Assistant Professor of Plant Science Department at NDSU. Bill Schuh: Soil Scientist of ND State Water Commission, Bismarck, ND. Steve Miller: collaborator, Fairmount, Richland County, ND. Michael Sauer: water quality specialist of ND Department of Health, Bismarck, ND. Steve Fisher: coordinator of Lake Agassiz RC&D, Fargo, ND. Gary Sand: Associate Professor of Biological Systems Engineering Department, University of Minnesota, St. Paul, MN. Richard G. Allen: Professor of Civil Engineering, University of Idaho, Kimberly, ID. Training: Graduate students: Xiao Pang, Ishara Rijal, Junyu Yang, and Santosh Rijal. Farmers: besides Steven Miller and Mike Freeberg at the Miller's farm, we also reached several hundreds of farmers through MN-ND drainage forums, tile drainage field day, and state meetings. TARGET AUDIENCES: This project provides an opportunity for farmers, university students, state agencies, and professional communities to understand better on where the water goes and its environmental impact to the surface water system. Approaches are through a formal classroom instruction to 40 students, development of a new course on drainage engineering, and educating people via forums, invited talks, and field days. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Subsurface drainage (SSD) has become increasingly important in the Red River Basin. This research project conducted a comprehensive study on accurate evapotranspiration (ET) measurement along with shallow water table, soil salinity, remote sensing validate and calibration. A detailed water balance measurement from this project will benefit both the irrigation and the drainage communities. These include: (1) developed a new simple and cheap method to measure outflow from sump pump station, with an accuracy of 3% to the pump curve; (2) quantified ET difference between SSD and non-drained fields using eddy correlation method, and found a 9.4% difference from June 1 to September 2, 2009; (3) evaluated the soil moisture and soil salinity difference at different distance from the SSD drain line; and (4) will relate the water quality measurement to water balance, so that the total load for different chemicals can be estimated. The results will provide an overall impact of SSD for the water availability at the experimental site, and the developed methodology may be extended to the state and other places with similar agricultural water management practices.

Publications

  • (1)Scherer, T.F., and Jia, X. 2009. A simple method to measure the flow rate and volume from tile drainage pump stations. Applied Engineering in Agriculture. Accepted.
  • (2)Zhang, X., Shi, L., Jia, X., Helgason, C., and Seielstad, G. 2009. Zone mapping application for precision-farming: a decision support tool for variable rate application. Precision Agriculture. In press.
  • (3)Jia, X., Zhang, X., and Steele, D.D. 2009. Comparison of sensible heat flux measurements by a large aperture scintillometer and eddy correlation methods. American Society of Civil Engineers, World Environmental and Water Resources Congress 2008, May 16-20, 2009, Kansas City, MO.
  • (5)DeSutter, T. M., Jia, X., Steele, D.D., Scherer, T.F., Hopkins, D.G., and Pang, X. 2009. Impacts of tile drainage and sub irrigation on water quality in southeastern North Dakota. ASA-CSSA-SSSA, 2009 International Annual Meetings, November 1-5, 2009, Pittsburg, PA.
  • (6)Scherer, T. F., and Jia, X. 2008. A Simple Method to Measure the Flow Rate and Volume from Tile Drainage Pump Stations. American Society of Agricultural and Biological Engineers Annual International Meeting, June 21-24, 2009, Reno, NV.
  • (7)Jia, X., DeSutter, T. M., Scherer, T. F., and Steele, D.D. 2008. Simulation of water table and salinity changes in a subsurface drainage field by Hydrus-2D. American Society of Agricultural and Biological Engineers Annual International Meeting, June 21-24, 2009, Reno, NV.
  • (8)Jia, X. 2008. Impact of subsurface drainage on water availability in the Red River Basin. 2009 USDA-CSREES National Water Conference, February 8-12, 2009, St. Louis, MO.
  • (4)Jia, X., Rijal, I., Pang, X., DeSutter, T.M., Scherer, T.F., and Steele, D.D. 2009. Temporal and spatial distributions of soil moisture and soil salinity for undrained, subsurface drained, and subirrigated corn fields in North Dakota. ASABE 9th International Drainage Symposium. June 13-16, 2010. Quebec, Canada.