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New Rice Irrigation Offers Many Benefits
MISSISSIPPI STATE -- Mississippi State University is researching ways to make a new cultivation practice used by many Mississippi rice farmers more profitable.
About 50 percent of Mississippi's rice acreage is farmed using precision leveling and straight levees as farmers have moved away from the traditional levees that curve to follow the natural contour of the land. These new rice paddies follow a constant slope of the land, with straight levees cutting through the land at right angles to the slope of the field.
Tim Walker, a rice research assistant with the Mississippi Agricultural and Forestry Experiment Station, said precision- leveled fields with straight levees offer many advantages.
"Precision leveling addresses the environmental issue of water quality. With precision leveling, we can use 25 to 50 percent less water to flood our fields," Walker said. "We also have the ability to better manage the water once it's on the field."
Precision leveled fields typically have a 0.1 percent slope, or a 1 foot drop for every 1000 lateral feet, and have levees spaced between 150 and 300 feet apart. Risers at the high end allow water to flood the field, and gates are conveniently located at the turn-rows to either keep water on the field or let it escape.
The research originally was geared to reduce surface water contamination by limiting the amount of nutrients in the water allowed to drain off the rice fields. But as this work progressed, the issue of the fertility of the disturbed soil became more important.
"With precision leveling, you cut away the soil in high areas and put the cut soil in low areas, leveling the land to form the constant slope you want," Walker said. "The problem is that we end up with a lot of areas in the field where the topsoil is subsoil, which has a lower fertility status."
About a year ago Walker began trying to determine what fertilizer rates and amendments can be added to the soil to improve fertility and still remain cost-effective.
"We have to determine what we can do to limit the time it takes for some yields to come back to the levels they were before the field was leveled," Walker said. "We're trying to make sure we have enough fertilizer budgeted into our nutrient management plans for cut soils."
Precision leveling is a long term investment. In addition to the cost of leveling the field, there is a reduction in yields for some time afterwards.
"With the water, diesel and labor savings that these fields offer, most growers see the benefit of precision leveling in five to 10 years," Walker said.
The Mississippi Rice Promotion Board is sponsoring this on- farm research which is being conducted at MSU under the direction of Billy Kingery, MAFES rice researcher.
Travis Satterfield, Rice Promotion Board member and rice farmer in Bolivar County, said the research was initiated after conventional tests could not determine why soil fertility was low on recently leveled land.
"In certain areas where we had cuts and a lot of dirt was removed, we were seeing some difference in plant heights, vigor and a reduction in yield, even though conventional soil tests showed the major nutrient levels were OK," Satterfield said. "We needed research done to see what could be done to bring those areas with deep cuts back to full capacity production."
Satterfield said he thinks most rice production soon will be on precision-leveled land and this problem will continue to develop unless it is solved.
"This is one area where we identified the problem and the Mississippi Rice Promotion Board was able to put some money into trying to correct that problem," Satterfield said.