SPUR-91: A computer simulation model of the production and use of rangelands

This article presents the model SPUR-91 for the computer simulation of the productivity and use of rangelands, which σας developed by the U.S. Dept. of Agriculture-Agriculture Research Service. The design of the system was targeted to create a physically based model for the comprehensive rangeland ecosystem simulations. The simulation model could serve as a tool aiding research and management decisions which has the capacity to improve the ability of the rangeland managers to predict answers related to various management activities. Specifically, the model has the ability:
1. Predict changes in water quantity and quality resulting from management practices,
2. Simulate rates and amounts of runoff and sediment occurring in stream channels,
3. Predict by species or species-groups the daily biomass and nitrogen content of live and dead rangeland vegetation,
4. Simulate the spatial heterogeneity of rangeland communities,
5. Predict the response of vegetation to herbivory, nitrogen availability, and water availability,
6. Simulate herbage removal by cattle and wildlife from rangelands,
7. Provide sufficient detail to allow for simulation on sub-divided watersheds,
8. Provide useful information for environmental impact analysis.