Impact of Drainage Water Management on Soil and Water Quality and Crop Production
Sustainable Production
Abiotic stressField management SustainabilityWater supply
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Xinhua Jia, North Dakota State University
Co-Principal Investigators:
Thomas F. Scherer, North Dakota State University
Project Code:
Contributing Organization (Checkoff):
Institution Funded:
Brief Project Summary:

Due to above average precipitation and increased soil salinity on farmland that delayed or prevented planting and harvesting, the installation of subsurface drainage (tile) has become very common in the Red River Valley (RRV). Tile drainage improves subsurface water management because it removes excess water from the root zone. Soybeans benefit significantly from tile drainage because soil wetness and salts are the major factors for iron chlorosis and yield reduction. However, tile drainage water also contains dissolved salts and nitrate, which may contaminate surface water systems. Drainage water management (DWM) using controlled drainage and subi1Tigation (SI) can reduce the total...

Unique Keywords:
#water quality & management
Information And Results
Final Project Results

Updated August 8, 2017:

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Executive Summary

Impact of drainage water management on soil and water quality and crop production

Xinhua Jia and Thomas Scherer
Department of Agricultural and Biosystems Engineering
North Dakota State University, Fargo, ND 58108

June 30, 2017

Soybean is very sensitive to soil moisture and salinity conditions in the field. For the last twenty years, it has been difficult to plant or harvest many fields in the Red River Valley due to wet conditions. To solve this problem, tile drainage was quickly established in the region to remove excess water, reduce the soil salinity, and create critical windows of time for planting and harvesting. However, tile drainage water contains high soluble chemicals, including nitrate and dissolved minerals (salts) that can pollute our streams and lakes. In this study, we used six farm fields, four in Clay County, Minnesota, and two in Richland County, North Dakota, to monitor the nutrients and salts coming out from tile drainage outlets. We also checked the nutrients and salts in the six fields and compared their changes due to tile drainage. Crop yields were also compared in the six fields in order to evaluate the tile drainage impact.
In our research, we compared four different ways to manage the water and reduce the nitrate and phosphorus loss from a tile-drained field. These included conventional drainage, meaning the drainage water is directly discharged to a surface ditch; controlled drainage, which has a control board at the drainage outlet to control the time and amount of drainage flow; and subirrigation, which adds water back to the tile drained field at the control drainage structure. We also have two check fields, which only have surface drainage and no tile drainage. Our results indicated that nitrate nitrogen concentration in the tile drainage water (7.15 ppm) was five times higher than that in the surface drainage ditches (1.35 ppm). With controlled drainage, the nitrate was retained in the field. Phosphorus monitoring showed that both surface and subsurface flows contained phosphorus concentrations that exceeded the water quality standard. A higher amount of salts were found in tile drainage flows, when compared to the surface ditch water. With good water management practices in the field, we can help retain the nitrate and salts in the field in late spring and summer, and improve the water quality in our surface water environment.
Soil salinity is a big concern for many soybean growers because it can cause soybean iron chlorosis and reduce the soybean yield. Tile drainage is the only effective way to permanently leach out the salts, reduce the soil salinity, and keep the land productive. We monitored the soil salinity changes in the field using soil sampling and salinity maps. Our results clearly indicated that soil salinity was reduced with tile drainage. The biggest benefit to the soybean growers and the soybean industry is to understand that through drainage water management, we can achieve a better yield in the field and maintain a clean water for all citizens in the Red River Valley.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.