In-Season N Reduced Nitrous Oxide Emissions in Corn.

Corn receives more N fertilizer than all other U.S. crops.  Most N is applied before planting, at a time of year when soils tend to be moist and loss processes may occur.  Delayed N application may reduce both nitrous oxide production and nitrate leaching by minimizing the soil nitrate pool during this vulnerable period.  An experiment was initiated in 2012 comparing nitrogen management and drainage effects on corn yield, nitrous oxide emissions, and nitrate in drainage water.  Essentially no nitrous oxide was released in 2012, a drought year.  In 2013, in-season N application reduced nitrous oxide emissions by 75% compared to pre-plant N application; in 2014 the reduction was 40%.  In both years, in-season N application increased corn yield by about 20 bushels/acre relative to pre-plant application, and nitrate concentration in drainage water was also reduced.