Multiple Inlet Approach to Reduce Water Requirements for Rice Production

Traditional flooded rice production utilizes a well or riser in the highest-elevation portion of the field and waterspills into lower paddies as the upper paddies are filled. In an alternative method known as multiple-inlet irrigation, ratherthan discharging directly into the highest paddy, a pipe is connected and gates or holes water each paddy concurrently insteadof each receiving overflow from a higher paddy. The objective of this research was to investigate whether a multiple-inletapproach would result in less water being pumped for rice production than conventional flooding, when applied on production-scale fields by the regular farm employees. On-farm water use studies were conducted during the 1999 through 2002growing seasons. The studies consisted of 14 paired fields located close together, with the same cultivar, soil type, plantingdate, and management practices. One field was randomly assigned as a conventionally flooded field and the other wasassigned as multiple-inlet rice irrigation. Flowmeters were installed in the inlets to both fields and the farmers provided yielddata. The multiple-inlet method required 24% less irrigation water than conventional flooding and produced 3% more yieldand 36% higher irrigation water use efficiency than conventional flooding. These findings can lead to easing the groundwatershortages being experienced in Arkansas and other rice-producing areas.