IMPACT OF DIFFERENT WATER MANAGEMENT SCENARIOS ON CORN WATER USE EFFICIENCY.

This study investigated the water balance, crop yield, and water use efficiency (WUE) of a water table management system compared to a conventional drainage system at three nitrogen levels. A two-year field study was conducted using three blocks; each block was composed of two water management treatments: controlled drainage with subirrigation (CD-SI) and conventional or free drainage (FD). The water table depth was maintained at 60 cm below the soil surface in the CD-SI plots. Three nitrogen treatments (low, medium, and high) were applied in strips across all blocks. The seasonal water balance indicated surplus water conditions in the CD-SI plots, while the FD plots had deficit conditions. In 2008 and 2009, the corn grain WUE for the FD plots was 2.49 and 2.46 kg m^-3 respectively. The corn grain WUE for the CD-SI plots was 2.43 and 2.26 kg m^-3 in 2008 and 2009, respectively. The WUE of corn grain responded to the water treatments (p < 0.05) in 2009 but not in 2008. In 2009, at low and high nitrogen levels, the water management treatments demonstrated significant differences (p < 0.05) in grain yields. However, water management demonstrated no significant effect (p > 0.05) on grain yields at the normal nitrogen level. Furthermore, the two water treatments had no effect on the aboveground dry biomass yields in both years. [ABSTRACT FROM AUTHOR]