Methods, techniques, and considerations for subirrigation practices in the Red River Valley of the North

摘要

Throughout the Midwest, drain tiles are being installed to manage soil moisture and increase crop yields on many traditionally low productivity and high salinity wet fields. As the rate of tiling has increased over the last decade, so has the interestin subirrigation (SI), the process of adding water to a tile drainage system to provide necessary water to crops during high crop water demand periods. The SI application uses existing drain tile systems and control structures, retrofitted with pumps, to deliver irrigation water back into the plant root zone when it is needed. The SI system offers farmers a cost-effective alternative to above-ground irrigation on tile drained land. However, many factors need to be considered to determine if the land issuitable for SI application, such as topography, soil type, irrigation water source, tile spacing, control structure type, water quality, and irrigation scheduling. The inherently flat land in the Red River Valley of eastern ND and west-central MN is some of the most suitable land in the nation for SI application. Its flat topography makes controlling the water table and moisture content easy with a minimal number of control structures. The fine soil structure and narrow spacing 9.1-12.2 m (30-50 feet)are common for tile drainage, which also has proven to be adequate for subirrigation of deep root crops in two research fields conducted in southeast ND and west central MN. By combining tile drainage with subirrigation, producers will have confidence in achieving high crop yields, regardless of the natural weather conditions during the growing season. In this paper, we will discuss the methods, techniques, and considerations as well as current status and challenges for SI practices in the Red River Valley. Two case studies on SI application will also be discussed.