Nitrogen Management With Nitrification Inhibitors in Corn.

Two of the avenues of Nitrogen (N) loss common in Kansas soils are denitrification and leaching. By minimizing these losses, producers can maximize yield with lower input costs and less impact on the environment. The use of nitrification inhibitors with anhydrous ammonia to retain N in the ammonium form can potentially lower these N losses and increase NUE recovery. This project was initiated in the fall of 2011 to evaluate the effectiveness of two nitrification inhibitors with anhydrous ammonia, as well as, compare the effect of spring versus fall application as tools for reducing N loss. Three very different soils were chosen: a high yielding silt loam site near Manhattan, KS, with moderate potential for denitrification loss; a lower yielding silt loam site near Ottawa, KS, with a high potential for denitrification loss; and a very high yielding irrigated, sandy loam near Rossville, KS, with a very high potential for leaching loss. Conditions in the eastern part of Kansas were not conducive to high losses of N through leaching or denitrification due to the low level of rainfall throughout the 2011 winter and 2012 growing season for no-till corn. However, there was a short period during May and early June where approximately 3 inches of rain was received during a four-day period. As a result, yield responses to the nitrification inhibitors were minimal, but some response to inhibition in yield and N recovery was seen with fall application at Manhattan. Differences between spring and fall N applications were also observed at Rossville.