Impact of Irrigation Scheduling on Corn Yield and Water Balance in Sandy Soils of Central Minnesota Using the EPIC Model.

Efficient irrigation scheduling is critical in sandy soils to achieve optimum yield and maximum net benefit with minimum environmental concerns. The Environmental Policy Integrated Climate (EPIC) model was used to study the impacts of autoirrigation of corn on crop yield and soil water balance during 2019–2021 at −300 and −450 kPa for loamy sand (Becker) and sandy loam (Westport) sites in Central Minnesota, respectively. Moreover, four irrigation scheduling methods were compared, i.e., checkbook (CB), EPIC-autoirrigation (EPIC), irrigation management assistant (IMA) and soil-moisture-based (SM). The simulation results indicate that irrigation water requirements under CB, EPIC, IMA and SM averaged 155.6, 141.2, 76.1 and 151.6 mm, respectively, on top of 627.5-mm annual precipitation. EPIC simulations indicate that the CB, EPIC, IMA and SM methods, averaged two sites, produced corn yields of 12.3, 12.6, 11.1 and 12.2 t ha⁻¹, with deep percolation losses of 198.5, 171.9, 163.3 and 189.2 mm, respectively. EPIC appeared to be an effective alternative to the labour-intensive SM method for irrigation management to obtain maximum corn yield and economic benefits, while the CB and IMA methods had higher deep percolation and soil water stress, respectively.