Reducing Nitrogen Runoff
After a dry summer, reduced corn yields generally results in excess soil nitrogen (N) and excess N leaching in the fall, winter, and spring. Most farmers fertilize for maximum yields and hope that the weather cooperates. When corn yields are reduced due to drought, the excess N that was applied is often lost through leaching when the rains return or it may be lost to the atmosphere as ammonia gas under saturated soil conditions through denitrification. Soil N runoff is lost at 100X higher rates than soil phosphorus and N is a major pollutant in Lake Erie and the Mississippi River. Keeping nitrogen in the soil should be a major goal of every farmer, so keeping N in a form that is both plant available but not soluble would be a great accomplishment. Microbially bound N is both plant available but also not soluble. When soils get dry, N is often not plant available but when these soils finally get wet, the soluble N can be lost by leaching or denitrification. The best way to reduce these ...