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Pivot-irrigated rice promising
Mention rice production and most people envision a crop standing in a paddy. That’s not what you see on one of Donny DeLine’s fields near Sikeston, Missouri.
Hidden among several fields of corn is a 68-acre field of rice under a half-swing center-pivot irrigation system. Yet, there are no levees, and there’s very little standing water to give it away as anything more than a field of small grain.
“One of the biggest benefits is it gives us one more option on our center-pivot fields,” says DeLine, who grows rice, corn, soybeans, wheat, and cotton in Missouri, as well as neighboring Illinois, Tennessee, and Arkansas under the banner DeLine Farms Partnership. “It not only lets us take advantage of the rice market as it rallies, but also it provides another rotation crop on irrigated fields.”
According to DeLine, the field is just one of a handful that are part of a Valmont Irrigation Circles for Rice project to study the feasibility of rice under pivots in the U.S. The goal is to conserve water, increase grower profitability, and help ensure an adequate worldwide food supply. As part of the project, DeLine is also working with the University of Missouri.
“The practice of pivot-irrigated rice does require some modifications of the pivot,” he says. “For example, we have oversize tires on all of the towers, plus there are tracks on the last two towers since they travel the greatest distance. We have to keep the field pretty muddy, so we need enough traction and flotation to keep the unit moving. Of course, we also use drop nozzles on all the spans.”
The other challenge, says DeLine, is weed control. One of the benefits of standing water in traditional rice production is that the water inhibits the growth of most weed species. That is not the case in mud. Arkansas trials in 2010 revealed that farmers spent approximately 7% more on herbicides and 37% more on pesticides under pivots compared to flood irrigation. Circles for Rice participants, however, spent nearly 76% less on labor, 34% less on diesel, and 63% less on repair and maintenance. They also used about half as much water.
“If you look at water use and pumping costs alone, we’re going to be about $60 per acre ahead,” DeLine says. “And we definitely have fewer man hours involved. I don’t know if you can put a price on convenience, but that’s worth a lot on years like this last one, too.”
Fertility costs the same
DeLine reports that his fertilizer costs are about the same either way, while chemical costs have admittedly been a little higher. On the other hand, there’s very little fieldwork required beyond normal seedbed preparation, and there’s no need for precision leveling or contour levee construction.
“Right now, we have the pivots set up to put on about 3∕10 to 4∕10 of an inch of water in 14 hours,” he says. “Then we let it set for 14 to 20 hours and send it back around again. At the same time, we’re putting about two thirds of our nitrogen on through the pivot. So we also have the savings of not having to pay for an airplane to fly nitrogen on.
“Once the rice is planted and it’s up, it’s pretty simple to manage. Our biggest problems this year were the wind and the weather, which kept us from getting our postemerge chemicals applied at the ideal time,” DeLine concludes, noting that rice herbicides and cotton, which was in a nearby field, do not get along. “Consequently, we had more weed pressure than normal. But overall, I think rice under pivots holds a lot of promise.”