Author
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Shaffer, Marvin |
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Submitted to: Journal of Soil and Water Conservation Society
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/1/2002 Publication Date: N/A Citation: N/A Interpretive Summary: Computer models of the nitrogen (N) cycle are now widely used in agriculture to assist with management of chemical fertilizers and manure. The paper reviews the basic types of N models, modeling techniques, and required databases. The accuracy of N models along with their strengths and limitations are discussed in a management context. Tips are provided on model and database selection and model application to environmental problems such as NO3-N movement to groundwater and greenhouse gas emissions to the atmosphere. Action agencies, extension, and environmental consultants should find the paper to be an excellent source of summary information on N computer models and their application to agricultural management and environmental protection. Technical Abstract: Simulation models of the nitrogen (N) cycle have been used for well over 20 years to help estimate NO3-N leaching, soil residual NO3-N, fertilizer N requirements, soil organic N status, and gaseous N emissions associated with agriculture. These models have been coupled with simulations of other related processes such as water and solute transport, crop growth, soil chemistry, temperature regimes, and management to make more complete models of cropping systems. At the core of these tools have been databases for soils, climate, model coefficients, and field/farm/watershed management scenarios. This paper reviews the basic types of N models, modeling techniques, and required databases. The accuracy of N models along with their strengths and limitations are discussed in a management context. Tips are provided on initializing N constituent pools, on using N models in Geographical Information System (GIS) applications, on developing confidence bands for N model output, and on using Web-based N models. Finally, methods are described to analyze simulated NO3-N leached, nitrous oxide (N2O) emissions, and N use efficiencies. |
