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 water spills into lower paddies as the upper paddies are filled. In an alternative method known as multiple-inlet irrigation, rather than discharging directly into the highest paddy, a pipe is connected and gates or holes water each paddy concurrently instead of each receiving overflow from a higher paddy. The objective of this research was to investigate whether a multiple-inlet approach 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 2002 growing seasons. The studies consisted of 14 paired fields located close together, with the same cultivar, soil type, planting date, and management practices. One field was randomly assigned as a conventionally flooded field and the other was assigned as multiple-inlet rice irrigation. Flowmeters were installed in the inlets to both fields and the farmers provided yield data. The multiple-inlet method required 24% less irrigation water than conventional flooding and produced 3% more yield and 36% higher irrigation water use efficiency than conventional flooding. These findings can lead to easing the groundwater shortages being experienced in Arkansas and other rice-producing areas.