NITRATE LEACHING INDEX

Authors: VAN ES, HAROLD - CORNELL U, ITHACA, NY; Delgado, Jorge

Submitted to: Encyclopedia of Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/9/2003
Publication Date: 9/21/2004
Citation: Van Es, H.M., Delgado, J.A. 2004. Nitrate leaching index. Encyclopedia of Soil Science. p. 1-3.

Interpretive Summary: On average, current N use efficiencies (NUE) are being reported to be about 50%, and the economic worldwide average N losses are equivalent to millions of U.S. dollars. The current NLI is a quick assessment tool that evaluates the N leaching potential based on basic soil and climate information. It is the basis for many current nutrient management planning efforts, but has considerable limitations due to (i) an oversimplification of the processes affecting N leaching, and (ii) a lack of management considerations. Improved N management in the landscape requires a new NLI that considers the complex interactions of climate conditions, soil characteristics, crop type, management and off-site factors, and can integrate management scenarios. A tiered approach is proposed to achieve these multiple objectives. A new NLI needs to be developed with mechanistic dynamic simulation models (e.g., GPFARM, EPIC, LEACHM, NLEAP, GLEAMS, RZWQM) that can account for the complex N pathways, transformations and interactions with other nutrients.

Technical Abstract: On average, current N use efficiencies (NUE) are being reported to be about 50%, and the economic worldwide average N losses are equivalent to millions of U.S. dollars. The current NLI is a quick assessment tool that evaluates the N leaching potential based on basic soil and climate information. It is the basis for many current nutrient management planning efforts, but has considerable limitations due to (i) an oversimplification of the processes affecting N leaching, and (ii) a lack of management considerations. Improved N management in the landscape requires a new NLI that considers the complex interactions of climate conditions, soil characteristics, crop type, management and off-site factors, and can integrate management scenarios. A tiered approach is proposed to achieve these multiple objectives. A new NLI needs to be developed with mechanistic dynamic simulation models (e.g., GPFARM, EPIC, LEACHM, NLEAP, GLEAMS, RZWQM) that can account for the complex N pathways, transformations and interactions with other nutrients. This is especially important for the evaluation of cases where organic N sources are being applied to the fields, which are generally of greatest concern with nutrient losses.