Combination Subsurface Irrigation and Drainage Systems in North-Central South Dakota

The 340,000 ha Lake Dakota Plain area in north-central South Dakota has the topographical and soil characteristics required for the use of combination subsurface drainage and irrigation systems. Corn yield data from a research site and a county-wide reporting service were used to determine that DRAINMOD, a water balance and corn yield estimation computer model, could be employed to assess the feasibility of using a combination system for the area. Three soils ranging in texture from a sandy loam to a silt loam and 19 years of climatic data were used in the feasibility analysis. Drain line spacings were determined for average yield goals of 90, 95, and 100% of estimated maximum corn yields for each soil. There are possibilities for the economical use of combination subsurface irrigation and drainage systems in the Lake Dakota Plain area.