Wheat Growers Should Consider Snow Cover with Nitrogen

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Brookings, South Dakota (December 6, 2007)--Producers now considering nitrogen applications for no-till wheat must consider snow cover.

This is according to Ron Gelderman, South Dakota State University's Soil Testing Lab manager.

Gelderman said many producers, facing record-high fertilizer prices, want to apply nitrogen now to avoid the possibility of higher prices in the future or shipment delays in the spring.

"We've looked at an SDSU study, from 2006-2007, that was done at seven winter wheat locations and seven spring wheat locations, covering the wheat (growing) areas of western and central South Dakota," said Gelderman. "It showed that when there was significant snow cover and N was surface broadcast, yields averaged about 18 percent lower than where N was placed in the soil."

Gelderman said this study, which used urea nitrogen, was a good indicator that application to snow-covered fields was a poor choice.

"On locations with little snow, winter applications were similar to in-soil applications," he said. "Applications to frozen fields without snow cover are not recommended on sloping fields because of runoff potential."

While fall, early spring, and late applications, some as late as the five-leaf stage, all had similar yields, the study Gelderman mentions showed soil application led to the highest yields over all sites.

"The reason behind the lower yields is not clear since a non-volatile N fertilizer was also used and had similar yields to the urea treatment," he said. "So it doesn't appear gaseous N loss was the issue. In addition, runoff was limited on these relatively level sites."

Gelderman said the South Dakota Wheat Commission should be recognized for funding this practical study. "This data supports previous work done on tilled fields, and it indicates application to snow should be avoided," he said. "Producers in the state can immediately use these recommendations."

Contact:
Ron Gelderman
605-688-4770