Quantifying the effects of rangeland conversion on ecosystem functions: Linking land use systems to enhance farm profitability

View the project final report

Commodities

• Agronomic: grass (misc. annual), grass (misc. perennial)
• Nuts: almonds
• Animals: bees, bovine, sheep

Practices

• Animal Production: grazing management, grazing - continuous, range improvement, rangeland/pasture management
• Crop Production: nutrient cycling, nutrient management, pollinator habitat
• Education and Training: demonstration, extension, farmer to farmer, on-farm/ranch research
• Farm Business Management: budgets/cost and returns, land access
• Natural Resources/Environment: biodiversity, carbon sequestration
• Pest Management: weed ecology
• Production Systems: integrated crop and livestock systems, organic agriculture
• Soil Management: organic matter, soil analysis, soil chemistry, soil microbiology, soil quality/health
• Sustainable Communities: sustainability measures

Conversion of land use in western states has increased over the past few years. In California, land use conversion is typified by depletion of rangeland to cropland and to urbanization. Between 1983 and 2008 for example, approximately 20,000 acres of prime rangeland were lost every year, mainly in the Central Valley region. While it is generally recognized that the rapid and widespread conversion of rangeland in the absence of sound conservation management would negatively affect ecosystem services, little is known about the full range of ecosystem changes (negative and positive) that occur on converted grounds of rangeland. This project will provide new insights into the essentials of ecosystem function changes during rangeland conversion to cropland. The project will also examine areas where rangeland functionality is weak in terms of soil health and develop extension and educational strategies to propose remediation/conservation measures that optimize rangeland ecosystem functions while maintaining and improving rangeland economic returns. We will use field data collection and computer modeling to evaluate the impacts of rangeland conversion on ecosystem functionality by comparing environmental quality data between rangeland and almond fields. We will set up and monitor three study sites, each with a rangeland site adjacent to almond orchards over a period of three years in collaboration with producers. We will collect field data to compare how infiltration, water flux, evapotranspiration (ET), soil nutrient content, runoff, soil microbial activity, soil carbon, plant production, plant, vertebrate and invertebrate species diversity, weed infestation, and soil compaction vary between rangeland and almond orchard sites. We will use modeling to evaluate the impacts of various conversion arrangements on hydrology at a watershed scale and explore the potential for linking and integrating production systems (i.e. mixed production approach) that can enhance overall ranch and farm profitability. We will also utilize the exiting literature to identify the institutional requirements for building resilience in rangelands, and apply those insights in analyzing the existing policies and institutional mechanisms for the governance of rangelands in the Central Valley of California. We will monitor the initial costs of converting rangeland to cropland and costs associated with maintaining recently established cropland given potential changes in ecosystem functions. We will monitor revenue per acre earned from recently converted cropland across various potential crops and compare to returns earned over time. Data collected will be used to construct a simulation model to test economic implications of conversion over time. We expect this project to lead to improved recommendations for conversion of rangelands in California and western states in order to help optimize environmental sustainability of rangelands. The project will provide science-based information to assist producers and ranchers determine which conservation practices/arrangements may work in their operations. The installation and results of this project will be incorporated into Extension and Outreach programming and other educational activities that will be released through a variety of outlets to inform producers and ranchers about the potential ecosystem changes that occur following conversion of rangelands.

The goal of this project is to provide insight into the basics of negative and positive ecosystem function changes during rangeland conversion to cropland. The project will propose measures to optimize rangeland ecosystem functions and will also explore the potential for establishing more integrated yet diversified agricultural production systems when land use changes occur to improve ecological sustainability. The specific objectives of this projects are to:

1. Establish field study sites for educational demonstration of rangeland conversion to cropland;
2. Evaluate the impacts of rangeland conversion on ecosystem functions (plant production, species diversity, soil condition and water budget) at field scales;
3. Use modeling to evaluate watershed scale impacts of selected ecosystem functions of rangeland conversion to cropland;
4. Synthesize the relevant literature to identify the institutional requirements for enhancing resilient rangeland systems, and assess the performance of existing institutional mechanisms for the governance of rangelands and their adequacy in promoting sustainable and resilient working landscapes.
5. Evaluate the on-farm and off-farm costs of rangeland conversion to cropland and costs of maintaining converted cropland given potential changes in ecosystem functions over time.
6. Develop appropriate farm and watershed level management strategies to optimize farm/ranch profitability and ecological sustainability; and
7. Disseminate research findings to