Impacts of Controlled Drainage and Subirrigation in The Red River Valley

Abstract

Drainage water management via controlled drainage (CD) and subirrigation (SI) has shown positive effects on water quality. To determine the impact of CD and SI in the Red River Valley (RRV), data from two fields, each with CD and SI, were analyzed. Water samples taken during SI from a North Dakota field during 2012-2018 were significantly different from those taken during CD and free drainage (FD). This was likely due to the SI water source of marginal quality, which also impacted soil quality near the drain tile. Three Minnesota fields were compared during 2013-2019, each with differing drainage practices. Results from a rainfall event showed an intermediate water table depth in the CD and SI field, along with a higher phosphate but lower nitrate concentration in surface runoff samples compared to subsurface drainage samples. Despite differences found between these fields, correlation between drainage practice and crop yield was not present.