Control mechanisms to reduce fertilizer nitrogen movement into groundwater

SINCE groundwater is the source of drinking water for about 50 percent of the US. population, there is increasing concern over the expanding level and extent of groundwater pollution. Fertilizers are one of several nitrogen (N) sources that may contribute to the accumulation of nitrate in groundn-ater. Some control strategies suggest that greater federal involvement in limiting N fertilizer usage may be needed to stop the spread of nitrate contamination in our groundwater supplies. Any discussion on developing K fertilizer use regulations should note these four points. First, policymakers need to have a good understanding of the N cycle in order to approximate the specific contributions of nitrates from each of the sources. This knowledge is needed in order to determine what can and cannot be achieved by restricting N fertilizer applications and in assessing costs versus benefits. Second, each location and situation is unique. Broad general regulations designed to address the problem on a area-wide basis may not be effective in local situations. Third, the nitrate leaching potential from farmland can not be reduced to zero, even with a ban on S fertilizers, because the act of cultivation releases mobile nitrogen at times when it is not …