The Central sands region in Minnesota has coarse-textured soils and low available water holding capacities which makes irrigation essential to obtain economical yields for corn. Moreover, excess irrigation in these soils has the potential to contaminate ground and surface water sources through deep seepage of nutrients (applied as fertilizers) below the root zone of crop. This study compared four different irrigation scheduling methods which involve different principles and strategies, including weather-based, soil-moisture based and simulation-based approaches to compute irrigation requirements. Site-specific soil water retention curves (SWRCs) and irrigation trigger points (ITPs) were developed for two soils in Central Minnesota – Hubbard-Mosford complex and Arvilla sandy loam for irrigation scheduling using watermark sensors. Site-specific calibration resulted in better performance accuracy of watermark sensors as compared to other sensors. The study demonstrates that adoption of appropriate irrigation scheduling method in coarse-textured soils has the potential to significantly reduce agricultural water losses. Also, according to the results by using appropriate irrigation scheduling method it is possible to significantly reduce NO3-N leaching without significantly impacting corn grain production in coarse-textured soils.
