Submitted to: ASAE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 7/9/2000
Publication Date: 7/9/2000
Citation: Kenimer, A.L., Harmel, D., Torbert, H.A., Akbar, M.A., Searcy, S.A. Nitrogen losses from corn receiving conventional and precision-applied fertilizer. Proceedings of American Society of Agronomy. 2000. Paper No. 002073. Interpretive Summary: As agricultural producers are faced with increasing pressures to decrease costs, increase yields, and protect the environment, new techniques are needed to achieve these goals. One recently-developed farming practice is precision farming. Precision farming techniques consider how soil and crop conditions change over the field and allows different fertilizer or pesticide application rates at different locations within the field. The result is inputs are placed in the field where they are most beneficial to crop production. This prevents over application in areas where application is not needed or would not provide crop production benefits. The first year of this precision agriculture study on corn production in central Texas was unusually dry; however, runoff from eight storm events was measured. No significant differences in nutrient concentrations were found between the precision and conventional fields. Generally, nutrient loads from the conventional field were greater than those from the precision field. However, loads were greatly influenced by larger runoff volumes and sediment loads from the conventional field.
Technical Abstract: The association between agriculture and water quality degradation has placed increased pressure on agriculture to incorporate Best Management Practices (BMPs) to promote and sustain environmental quality. One recently-developed BMP being adopted by producers is precision farming. Precision farming techniques consider spatial variability of crop and soil conditions. Precision farming allows different fertilizer application rates at different locations within a single cultivated field. The combined factors of decreased costs, increased yield, and environmental enhancements make site-specific crop management a promising technique for Texas agriculture. Therefore, the objective of this study was to evaluate the impact of precision fertilizer application on surface runoff quality with a paired watershed study on corn production in central Texas. The results presented in this paper represent only one year of monitoring and, therefore, must be considered preliminary. Data collection will continue throughout the 2000 growing season. The first study year was unusually dry; however, eight storm events of sufficient magnitude for water quality sampling were monitored. Event mean nitrate concentrations averaged 4.87 mg/l for the precision field and 5.51 mg/l for the conventional field. No significant differences in nutrient concentrations were found between the precision and conventional fields. Generally storm loads from the conventional field were greater than those from the precision field. However, loads were greatly influenced by larger runoff volumes and sediment loads from the conventional field.