New irrigation strategies mean paradigm change for row rice

New irrigation strategies mean paradigm change for row rice

Furrow-grown rice requires more frequent irrigation than other row crops, and timing is more critical because rice has a shallower root system. For the last decade, University of Arkansas researchers have worked to optimize a recirculation system for irrigation water in row rice.

They have developed a continuous-flow, pitless tailwater system that uses a high-efficiency, variable-speed sump pump placed six feet below ground. The pump is connected to the top of the field using “lay-flat transfer tubing” which runs through the middle of the field to relay water from the bottom to the top and then feeds into the row-watered poly tubing. Pitless tailwater system management is similar to a flooded field. If the small area of the field at the bottom begins to recede, water can be added, giving the irrigator much more leeway on when to add water to the system. Even when ponded water at the bottom is nearly gone, soil in the field remains saturated.

This system used on row rice uses less water than a leveed rice field and requires less energy to operate the pump.

In field trials, the team has not used more than 19 acre-inches and as little as 12 acre-inches of irrigation water to produce more rice per acre than the state average of 170 bushels per acre

Additionally, using this system may offer higher yield potential compared to conventional furrow irrigated rice. The continuous flow of irrigation water provides a more consistent ground saturation, which may produce less of the greenhouse gas, nitrous oxide, than other irrigation methods. An added bonus is that consistent saturation appears to reduce pressure from pigweed, a very aggressive and highly difficult to control weed.

Overall, the system improved irrigation efficiency, decreased irrigation water applied and reduced greenhouse gas emissions without sacrificing yields.

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