HS948 Reduction of the Impact of Fertilization and Irrigation On Processes in the Nitrogen Cycle in Vegetable Fields with

The nitrogen (N) cycle is a set of transformations that affect N in the biosphere. Through a series of microbial transformations in the soil, N is made available to vegetable crops. Thus, knowledge of this cycle by which N passes from air to soil to organisms and back to air, and how the components of the cycle are affected by human activities, is required to design effective strategies for decreasing undesirable losses of N from vegetable production to the environment. Adequate management of fertilization and irrigation has always been recognized as one of the keys to successful vegetable production in Florida. Thus, fertilization and irrigation practices have aimed at supplying enough nutrients and water to ensure economical yields. Since up to 200 lbs/A of exogenous N are recommended for vegetable production in Florida, and fertilizer use efficiency seldom exceeds 75%, it is likely that fertilization affects the N cycle. Best Management Practices (BMPs) aim at reconciling the needs of economical vegetable crop production with those of environmental protection. Effective BMP implementation, therefore, requires an understanding of how current cultural practices affect certain processes in the N cycle in commercial vegetable fields. It is likely that a complete understanding of these issues by farmers and vegetable professionals will be a prerequisite for the success of the BMP program. The goals of this article are to (1) present the N cycle as it relates to crop production, (2) describe how fertilization and irrigation affect the processes within N cycle, and (3) explain how the proposed BMPs may help reduce the negative environmental impact of these cultural practices