PT - JOURNAL ARTICLE AU - J. A. Delgado AU - R. F. Follett AU - J. L. Sharkoff AU - M. K. Brodahl AU - M. J. Shaffer TI - NLEAP facts about nitrogen management DP - 1998 Oct 01 TA - Journal of Soil and Water Conservation PG - 332--337 VI - 53 IP - 4 4099 - http://www.jswconline.org/content/53/4/332.short 4100 - http://www.jswconline.org/content/53/4/332.full AB - The use of new computer models facilitates the quick extrapolation of research results into a wide variety of different agricultural systems. However, to predict the N dynamics across different fields, local information is still needed to initially calibrate and evaluate the local effectiveness of the model. One of these new computer software packages is NLEAP, which permits a rapid evaluation of a series of best N and irrigation management practices for a site-specific farmer's field. Information from several plant parameters was used to generate simulations: soil chemical and physical properties, irrigation practices, N management practices, amount of N in irrigation water, local climatological data, and additional factors. These computer simulations have detailed information about the crop N uptake, soil N biogeochemical transformations, water budgets, and the inorganic NO3-N content in the soil profile for vegetable and small grain rotations. Computer simulations with the new 1.2 version of NLEAP showed the potential to simulate residual soil NO3-N and transport of NO3-N in the soil profile over a wide variety of management scenarios. NLEAP 1.2 simulations suggest that the net process of NO3-N leaching can be reversed for coarse-textured soils. Coarse fragments on a volume basis are an important factor related to soil quality that need to be considered when using the NLEAP model in coarse-textured soils. These arc important NLEAP facts that can potentially contribute to protect and improve water quality.