Nitrogen management continues to be difficult due to transformations of nitrogen fertilizers that are possible when applied to soil and the uncertainties of weather (Cabrera et al., 2008). Nitrate fertilizer is subject to leaching (Randall et al., 2008) or denitrification (Coyne, 2008) depending on the water content of the soil and water movement through the soil. Ammonium forms of N can be fixed (Kissel et al., 2008), or can be transformed to nitrate through the activities of specific soil bacteria (Norton, 2008). Because of these and other processes, nitrogen use efficiency is low.
Soil Science Extension
University of Wisconsin Madison