Nitrogen Loss and Environmental Assessment Package (NLEAP GIS 5.0): Model

Authors: Ascough Ii, James; Delgado, Jorge; Lighthart, Nathan; Neer, Donna; Tebbe, Caleb; Shaffer, Marvin

Submitted to: Ag Data Commons
Publication Type: Other
Publication Acceptance Date: 8/5/2019
Publication Date: 8/5/2019
Citation: Ascough Ii, J.C., Delgado, J.A., Lighthart, N.P., Neer, D.L., Tebbe, C.R., Shaffer, M.J. 2019. Nitrogen Loss and Environmental Assessment Package (NLEAP GIS 5.0): Model. Ag Data Commons. https://data.nal.usda.gov/dataset/nleap-gis-50.

Interpretive Summary: The new Nitrogen Loss and Environmental Assessment Package simulation model (NLEAP-GIS 5.0) uses NASA World Wind technology to provide NLEAP with global information system technology (GIS) capabilities. This allows users to quickly assess the nitrogen (N) dynamics across agricultural landscapes with output visualization that allow the user to run long-term evaluations and identify with real-time dynamic color mapping the areas in the agricultural landscape that are more susceptible to nitrate leaching or that have high nitrous oxide emissions or other pathways of N loss. These powerful abilities allow for quick comparisons of N management scenarios to help framers, nutrient managers and conservationists make management decisions to improve N use efficiencies and reduce losses of reactive N to the environment. The NLEAP GIS 5.0 model, written in the Java programming language has GIS capabilities as provided by embedded NASA World Wind technology. These new GIS capabilites allow users to identify hot spots across the landscape and management practices that can increase N use efficiency. A N Trading Tool (NTT) analysis can be conducted on model output to determine the potential benefits of implementing best management practices and to quantify the amount of N savings that could be traded in future air or water quality markets.

Technical Abstract: The new model, the Nitrogen Loss and Environmental Assessment Package (NLEAP) with GIS capabilities (NLEAP-GIS 5.0), is an improved version of the previous model, the NLEAP GIS 4.2, which is an improved and renamed version of the NLEAP DOS program that was called the Nitrate Leaching and Economic Analysis Package (NLEAP). This new model written in the Java programming language has GIS capabilities with embedded NASA World Wind technology, providing users with newly added functions (e.g., improved visualization and color ramping capabilities) to help them quickly assess how management practices will affect nitrogen losses to the environment across risky landscape and cropping system combinations. The new model has the basic NLEAP GIS 5.0 console that is written in Fortran and C/C++, and the console contains the algorithms that are used to assess the effects of management practices on nitrogen pools and pathways for nitrogen losses, as described in the chapter by Shaffer et al. in the book, Advances in Nitrogen Management for Water Quality (2010). The model was significantly improved with the aforementioned technology, and this new geospatial tool for modeling N dynamics has: enhanced output visualization; real-time dynamic color ramping; output querying across land units; NTT technology for comparison of N management scenarios; and other capabilities. This new model interface enables users to quickly evaluate multiple practices employed over long periods of time and quickly assess hot spots across the agricultural landscape.