ABSTRACT
There are concerns about how agriculture will adapt to a changing climate and other environmental challenges during the twenty-first century in order to provide food security for the ever-increasing global population. Designing and implementing best nitrogen management practices will be critical in global food security efforts because of the positive correlation between nitrogen inputs and crop yield and between nitrogen inputs and nitrogen losses to the environment. Computer models are important tools that can help nutrient managers implement conservation practices on the ground to improve nitrogen use
7.1 Introduction .................................................................................................. 102 7.1.1 Nitrogen and Nitrogen Use Efficiency .............................................. 103 7.1.2 Nitrogen Tools Can Provide Opportunities to Assess Field
Scenarios ........................................................................................... 103 7.1.3 Basics of NLEAP-GIS 4.2 ................................................................ 106 7.1.4 NLEAP-GIS 4.2 Simulation Capabilities and Limitations .............. 107
7.2 Case Studies .................................................................................................. 109 7.2.1 General Methods and Procedures ..................................................... 109 7.2.2 Assessment under Rainfed Systems ................................................. 109 7.2.3 Assessment of Manure Systems ....................................................... 110 7.2.4 Synchronizing Fertilizer Application with Crop Uptake ................. 111 7.2.5 Use of Cover Crops to Mine and Recover Nitrate ............................ 111 7.2.6 Potential of Using NTT .................................................................... 112
7.3 Discussion and Conclusion ........................................................................... 113 Disclaimer .............................................................................................................. 114 References .............................................................................................................. 114
efficiency and reduce losses of nitrogen from agricultural systems. One such tool is the Nitrogen Losses and Environmental Assessment Package (NLEAP) with Geographic Information System (GIS) capabilities, Version 4.2 (NLEAP GIS 4.2), as well as the next generation NLEAP GIS 5.0, which allows geospatial analysis of multiple fields simultaneously. To use NLEAP GIS 4.2, users need to download location-specific Natural Resources Conservation Service (NRCS) SSURGO soil and weather databases from an Internet server and develop the nitrogen management scenario that they want to test. If desired, the more advanced NLEAP GIS 5.0 model can be used to conduct geospatial simulations and display nitrogen losses to the environment using embedded GIS-integrated NASA World WindTM technology and other tools for spatial statistical analysis. This advanced technology allows a collection of components that interactively display 3D geographic information within Java applications. This chapter includes a hands-on exercise that presents the NLEAP GIS 5.0 prototype with instructions on how to perform quick evaluations across large areas and identify the effects of best management practices. The user will also learn how to conduct a Nitrogen Trading Tool analysis and determine the potential benefits of implementing management practices and the quantity of nitrogen savings that could potentially be traded in future air or water quality markets.
