Managing Fertilizer Nutrients to Protect the Environment and Human Health

Nutrient management for production, profit, and environmental protection: Striking the balance Strategies to manage nutrients in crop production were first designed to maximize crop yields, an objective that became increasingly possible with the development of inorganic fertilizers during the past century. Later, as economic analysis of farm profitability became more sophisticated, strategies shifted somewhat toward optimizing economic returns from the fertilizer nutrients applied. Increased awareness of ecological principles during the past 50 years resulted in an improved understanding of the complex relationship between farming and ecosystems. Society, through government, increasingly recognized the danger of allowing agricultural practices that lead to deterioration of land and water resources. Various laws designed to protect water quality have targeted farming practices that result in excessive soil loss from erosion or excessive application of nutrients to soils. As the practical regulatory definition and enforcement of those laws evolves, the necessity of developing a consciousness of the ecological implication of farming practices takes on increasing economic significance to all farmers. Therefore, farmers not only must be concerned with balancing productivity and profit relative to fertilizer nutrients but they also must factor environmental concerns into their nutrient management strategies. While adequate levels of plant nutrients are essential for healthy and productive crop growth, some nutrients, particularly nitrogen (N) and phosphorus (P), pose environmental risks when improperly managed. In much the same way that pesticides are regulated to ensure the safety of the applicator and the food and water supply, there is a growing trend toward regulating the use of fertilizer nutrients. Just as farmers are required to keep records of pesticide applications, they may soon be required to do the same for fertilizer nutrients. Just as farmers need to know their cost of production to ensure a financially efficient operation, they have to be aware of environmental costs resulting from their practices. And just as farms need a sound financial plan, they also need a nutrient management plan. The goal of a nutrient management plan is to ensure the availability of adequate nutrients for crop production with minimal nutrient loss in runoff or leaching from the root zone. Such a plan should include • evaluation of site environmental concerns • evaluation of available soil nutrient status • calculation of nutrient application amounts based on realistic crop yields and available soil nutrients • appropriate nutrient application methods.