Effect of Water Management Practices on N Uptake and Grain Yield of Main and Ratoon Rice Crops.

Rice growth is dependent upon an adequate supply water which is becoming a limited resource. Producing one kilogram of irrigated rough rice is estimated to require between 600 to 2,000 liters of water, depending on the local climate, soil type, and rice variety. A field experiment was conducted to compare nitrogen uptake, yield and yield components in both main and ratoon rice crops under three water management practices. The water management practices included conventional flooding, intermittent irrigation and aerobic rice systems. Four nitrogen rates of 0, 100, 135, and 170 kg N ha^-1 were split applied one day before flooding and at panicle initiation. Rice yields were 8,670, 8,388, and 7,049 kg ha^-1 for the conventional flooding, intermittent irrigation, and aerobic system, respectively (P = 0.0002; LSD = 545). The yields were also significantly affected (P = 0.0001; LSD = 631) by nitrogen rates.