Managing Nitrogen to Protect Water Resources
Nitrogen management is a major factor in the quality of sugar beets and small grains. However, the potential benefits of this relatively inexpensive amendment to the crop can result in excessive applications. The mobility of the NO3-N ion through the soil and the large amount of N fertilizer used makes nitrogen management particularly problematic (Smika et al., 1977).
To avoid the risk of yield reduction, farmers may over-irrigate and over-fertilize their crops. However, the risk of contaminating surface and subsurface water resources greatly increases under this type of management. Emerging site-specific (variable rate) fertilization technologies can potentially reduce the excess use of fertilizers while maintaining crop production.
In summary, controlling surface applications, minimizing water and reducing agrochemical loss below the crop root zone are the most cost-effective methods of ground water protection (Hergert, 1986; Ritter, 1986; Power and Schepers, 1989; Fletcher, 1991; Watts et al., 2000).