Forms of nitrogen also have an impact on application. Nitrogen in the form of synthetic fertilizer, the report found, was more likely to have better management.
"Corn acreage receiving only commercial fertilizer dropped from 84 to 82% between 2005 and 2010, while corn acreage receiving manure increased from 16 to 18%. Between 2005 and 2010, management improved for farms using only commercial fertilizer: the share of corn acres not meeting the rate/timing/method criteria declined from 65% to 60%," the report says.
No improvement in nitrogen management was found on farms that used animal manure. Approximately 92% of corn acres receiving manure do not meet the rate, timing and method criteria.
USDA says a policy focus on improved nitrogen management on cropland will continue to be a conservation goal. Additional focus on manure management could be warranted as well, especially if the price of synthetic nitrogen climbs.
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