Submitted to: Soil Health Basis for Current and Future Production
Publication Type: Abstract Only
Publication Acceptance Date: December 7, 1994
Publication Date: N/A
Technical Abstract: Low nutrient use efficiency is a major factor contributing to the non-sustainability of agroecosystems. An understanding of soil processes controlling nutrient cycling will help maintain long-term productivity, enhance soil resources, and minimize adverse environmental effects. Agricultural systems are notoriously leaky, especially with regard to N. Recoveries of fertilizer N by corn have been reported to be on the average about 25% and, in any given year, corn may derive up to 75% of its N from the mineralization of soil organic matter (SOM). Efforts to improve our ability to predict and manage nutrient dynamics and soil quality in agroecosystems depend to a large extent on increasing our understanding of the processes that control SOM turnover. Nitrogen use efficiency is a concept that must include more than just fertilizer use efficiency. An ecological approach is required to address these questions, where the underlying focus is increased efficiency of resource utilization, both in time and space. An approach is described to assess soil-N use efficiency as opposed to fertilizer-N use efficiency. Application of this approach for predicting long-term status of the soil organic N pool is based on quantitative knowledge of soil N cycling, N inputs, N outputs, and interactions affected by yearly and seasonal climatic variations and soil type/landscape position effects. This information will increase our understanding of the processes that control N cycling in soil and improve our ability to predict and manage nutrient dynamics and soil quality in agricultural systems.