MODELING DEFICIT IRRIGATION EFFECTS ON MAIZE TO IMPROVE WATER USE EFFICIENCY

Deficit irrigation practices can save water and increase water use efficiency (WUE). This study was designed to evaluate effects of deficit irrigations, Management Allowed Depletion (MAD) levels, on maize fodder yields. The study was conducted at research area of the Department of Irrigation and Drainage, University of Agriculture, Faisalabad, Pakistan. Treatment effects were significant (p≤5%) with T1 (MAD of 30%) producing maximum fodder yield of 8933 kg ha^-1 while treatment T2 (MAD of 60%) had minimum fodder yield of 7994 kg ha-1 with water savings of 25% and water use efficiency (WUE) of 86 kg ha^-1 mm^-1. The GLEAMS model was calibrated to simulate the effects of relative management practices on hydrologic parameters. The GLEAMS model predicted runoff, deep percolation, and evapotranspiration reliably having percent difference of less than 5% between predicted and observed data but underestimated soil water contents. The scenario simulation, however, showed that keeping soil water contents within 50 to 90% of available water in root zone had maximum WUE. These results revealed that 2nd and 3rd irrigations were least sensitive and there is potential of water saving and increasing WUE during first quarter of vegetative growth, which can also be investigated for other crops.