Evaluation of Crop Yield, Water Productivity and Profitability of Modern Corn Hybrids Under Deficit Irrigation in Western Nebraska.

Deficit irrigation has been investigated as a valuable strategy for increasing water use efficiency in semiarid climates around the world. Field experiments were conducted in 2011 and 2012 at Brule, NE to evaluate yield, CWUE, IWUE and profitability of modern corn hybrids under full, deficit and rainfed conditions in semiarid environment of western Nebraska. Three irrigation treatments were applied to 16 most recent releases of corn hybrids: full irrigation which imposed minimal water stress on the crop, deficit irrigation which received 50% less irrigation water than full irrigation treatment and rainfed treatment which received no irrigation. Different yield trends were observed in 2011 and 2012 due to different growing conditions. Crop yield in 2011 was approximately 7, 12.5 and 14 t/ha for rainfed, deficit and full irrigation, respectively; suggesting that with sufficient rainfall deficit irrigation water use efficiency (IWUE) and profitability increases. When drought conditions increased in 2012, yield increased almost linearly with irrigation causing no change in crop water productivity and increase in profitability with each mm of irrigation water applied. There results suggest that with average seasonal rainfall, deficit irrigation was an effective irrigation management strategy in western Nebraska; thus, irrigation amounts can be reduced without causing significant yield and profitability penalty. Deficit irrigation is not an individual irrigation management practice and it should be used with other crop management practices for best results.