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ARS Home » Pacific West Area » Reno, Nevada » Great Basin Rangelands Research » Research » Research Project #433944

Research Project: Assessing Benefits of Conservation Practices on Rangelands and Pastures with the Rangeland Hydrology and Erosion Model

Location: Great Basin Rangelands Research

Project Number: 2060-13610-003-11-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Dec 15, 2017
End Date: Jul 31, 2021

Objective:
The primary objective is to construct the scientific foundation for documenting what is known and what is not known about the environmental effects of conservation practices and management actions on rangeland and pastureland hydrologic processes. The University of Nevada at Reno is undertaking a cooperative project with the Agricultural Research Service and the Natural Resources Conservation Service to evaluate if the Rangeland Hydrology and Erosion Model can successfully quantify soil erosion on pasturelands. A second aspect is to evaluate the impacts of adding compost to California annual grasslands to enhance the health of these plant communities under changing climates. Hydrologic function in the dynamics of an ecologic site is often poorly understood on pastureland and annual grasslands and poorly documented in ecological site descriptions. Accurate erosion predictions on pastureland and annual grasslands with the ability to estimate high risk areas for erosion will improve the conservation planning process and ultimately, the success of conservation management decisions. The project will determine if the addition of organic amendments (compost) can be added to California annual rangeland without negative effects to water quality or have negative environmental outcomes associated with the hydrologic function of the ecological site. The ARS, NRCS and University of Nevada Reno will 1) expand the RHEM model to pasture and annual grasslands, 2) test impacts on soil surface erosion and hydrologic function of compost applied rangeland, 3) provide course material for eco-hydrology training and 4) inform the hydrologic sections of ecological site descriptions.

Approach:
The University of Nevada at Reno will assist ARS in conducting rainfall simulation experiments to quantify rainfall/runoff relationships and mobility and transport processes of compost applications on 2 annual grass dominated ecological sites in California. Based on these findings the team will use this information to improve the USDA Rangeland Hydrology and Erosion Model’s ability to predict how this specific conservation practice will improve rangeland health, water quantity and quality of western rivers. The University of Nevada will assist ARS and NRCS in expanding the Rangeland Hydrology and Erosion Model (RHEM) to develop predictions of erosion on perennial pasturelands. The team will work with ARS hydrologic research stations across the U.S. to retrieve historic datasets on rainfall/runoff/soil erosion/sediment transport experiments on pastures. The team will then compare observed to predicted results of soil erosion. If beneficial and sufficient data exist them team will then develop an optimized model input parameters to enhance performance of the RHEM assessment tool and modify the RHEM User Guide to include instructions for using RHEM on pastures. The team will assist in the development of a workshop to train NRCS staff on dominant hydrologic and erosion process on rangelands. In addition the workshop will provide direct training on the RHEM assessment tool, information on the equations implemented in RHEM, and how to access and interpret model predictions using examples from across the United States for different ecological and climatic conditions.