Work focuses on improving rice farming productivity

Frances Gould, Schultz, Bruce  |  10/3/2013 1:05:52 AM

LSU AgCenter agronomist Dr. Dustin Harrell prepares an experiment at the Rice Research Station aimed at testing urease inhibitors that reduce nitrogen fertilizer loss from volatilization. Filter media are placed in cylinders to capture lost nitrogen that can be measured in the lab. Buckets are placed over the cylinders to prevent rainfall from affecting the tests. The results have shown that two new products, Arborite AG and N-Fixx, are as effective as Agrotain at reducing nitrogen losses.(Photo by James Leonards)

Photo By: LSU AgCenter

LSU AgCenter agronomist Dr. Dustin Harrell focused his work during the past year on improving rice farming productivity. Harrell evaluated fertilizer treatments to retard nitrogen volatilization.

For years, the only proven product that worked was Agrotain, a urease inhibitor. But two new products, Arborite AG and N-Fixx, came out in 2011 and 2012, respectively. Testing showed both are effective products, Harrell said.

Untreated fertilizer loses nitrogen at rates of 18-23 percent, compared to 5-6 percent loss with a urease inhibitor, Harrell said.

The LSU AgCenter agronomist is evaluating a number of new fertilizer products that have yet to be released, and he’s encouraged by what he has seen – although he says he can’t talk about the experimental material yet.

"I think there are still some improvements that are going to happen," Harrell said.

He also studied stubble management for growing a ratoon rice crop – treating stubble with four different methods. Some rice was left alone after the first harvest, some was cut to a height of approximately 8 inches, some was cut to the ground and some was rolled.

To his surprise, the best performer in 2012 was the stubble that had been cut to the ground, Harrell said, adding that that test plot actually was supposed to be cut only to an 8-inch height but was accidentally cut at ground level.

Harrell said the common assumption has been that a plant would need the nonstructural carbohydrates stored higher up in the plant to produce a ratoon crop.

He also said the disadvantage of mowing or rolling stubble is a later crop, and mowing to the ground may extend that delay by another week compared with the low harvest height and rolling.

The LSU AgCenter scientist said more work will be done to further understand the effects of the different stubble management practices.

In addition, more validation work was done in 2012 on the nitrogen soil test, called N-STaR, Harrell said, adding, however, "This year it did not work so well."

On two of the three locations where the test indicated a lower nitrogen rate, the yield was reduced compared with the farmer practice treatment, he said. On-farm validation work with N-STaR will continue in 2013, he said.

(This article was published in the 2013 Louisiana Rice Research Board Annual Report.)

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Please click on the links above to go to the Rice Research Board Reports home page, to go to the 2012 report, and to go to the PDF version of the 2013 report.

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