Sunday, November 12, 2006
20-7
Updates NLEAP – GIS Model (Stand alone).
Marvin Shaffer, Shaffer Consulting, 8225 Firethorn Drive, 8225 Firethorn Drive, Loveland, CO 80538, United States of America, Jorge Delgado, USDA-ARS-Soil Plant Nutrient Res., 2150 Center Ave, Bldg D, Suite 100, Fort Collins, CO 80526, Christoph Gross, USDA-NRCS-Nat Wtr/Cl Ctr Rm 1-2150C, 5601 Sunnyside Ave, Beltsville, MD 20705-5420, and Ronald Follett, USDA-ARS, Soil Plant Nutrient Research, 2150 Center Ave, Bldg D, Suite 100, Fort Collins, CO 80526-8119.
The Nitrogen Loss and Environmental Assessment Package (NLEAP) model has been updated to include a MS Windows user interface and simulation code refinements for surface residue decay, N2O soil gas emissions, crop rooting, and long-term analyses. GIS compatibility has been added along with a management database and connectivity to current NRCS soil (NASIS and SSURGO) and NRCS climate databases. NLEAP is directly connected to the new Nitrogen Index (NI) tool version 1.0 allowing users to make both Tier 1 (spreadsheet) and Tier 2 (application model) soil N loss analyses from the same spreadsheet tool. The revised NLEAP model provides a faster and more efficient means of integrating management effects with soil and climate information to estimate nitrogen (N) losses from agricultural fields including NO3-N leached, N2O and N2 soil gas emissions, ammonia volatilization, and surface wash-off of N. The NLEAP simulation algorithms are described in detail and a discussion is included regarding the status of international testing and validation for NLEAP. Application examples with analyses are included for a dairy farm (manure inputs) in the Midwest US and an irrigated area (fertilizer inputs) in Colorado . These examples should be of special interest to practitioners looking for improved methods to reduce N losses from agricultural fields.