A new economic brief from the USDA Economic Research Service finds that tactics used to promote appropriate nitrogen management aren't working as well as hoped, but a handful of improvements have been noted.
The study, which compared data between 2001 and 2010, found that a large share of cropland does not follow nitrogen management practices – amounting to 65% in 2006. But, despite the share that doesn't follow appropriate management practices, corn producers overall are applying less excess nitrogen.
A variety of factors were considered in the application and management practices of nitrogen on corn, including economic benefits, application methods and form of nitrogen.
The report found that changing economic conditions, not surprisingly, affects types and amounts of fertilizer used. Data from the Agricultural Resource Management Survey, the report says, indicates that corn acreage treated with nitrogen increased 18% between 2001 and 2010, as higher corn prices caused a shift in the amount of corn planted, and therefore the amount of nitrogen used.
Yet, economics can work the other way for nitrogen. The report estimates that higher nitrogen prices likely caused a reduction in the application of excess nitrogen. Prices for nitrogen fertilizer nearly doubled from 2000 to 2008, and by 2005 nearly one in four farmers said they reduced application rates to combat rising prices. When prices declined from 2008 to 2010, farmers were less likely to be judicious in nitrogen fertilizer use.
Trends in efficiency, whether through application or genetic traits in the plant itself, have also had an impact on the amount of nitrogen used. Corn acres with nitrogen applied above agronomic rates declined from 41% to 31% during 2001-10, a decrease that is likely tied to the decline of application rates per unit of output.
Overall, application method was not cited as a factor in increasing efficiency, however, and remains a key culprit behind losing nitrogen to the environment.
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.
Click here to read the full report.