University of Arkansas System Division of Agriculture scientists are testing products that can reduce loss of nitrogen from fertilizers applied to rice when irrigation or flooding are delayed.
If not quickly incorporated into soil, urea fertilizer will lose nitrogen because urease, a naturally occurring enzyme, converts urea to ammonia gas, a volatile chemical that evaporates readily, said Rick Norman, professor of soil science for the Division of Agriculture. He said as much as 40 percent of the nitrogen can be lost via ammonia volatilization from urea, the most commonly used nitrogen fertilizer in rice and other crops.
Norman presented his research on ammonia volatilization of nitrogen fertilizers during a tour of the Division of Agriculture's Rice Research and Extension Center near Stuttgart. The tour was one of the activities of the 2012 Rice Expo, held by the U of A System Division of Agriculture at the Grand Prairie Center at Stuttgart. Some 1,100 people came to see the division's research and extension programs related to rice, hear guest speakers, including Arkansas Gov. Mike Beebe, and participate in family-oriented activities.
Research projects highlighted during the RREC tour included rice breeding, disease and pest management, alternative irrigation strategies, weed control and other management practices.
"If you can get irrigation or flood on the field, to incorporate the urea into the soil, within two days on silt loam or seven days on clay soils, you'll be OK," Norman said. "But if flooding or irrigation are delayed, a urease inhibitor will help minimize ammonia volatilization loss from urea."
The most effective urease inhibitor in division tests, Norman said is NBPT, a chemical that was introduced under the trade name Agrotain in 2000. It is now available in other products, including Arborite, one of the products tested in Norman's research.