Project Overview
Information Products
Commodities
- Animals: bovine
- Animal Products: fiber, fur, leather, meat
Practices
- Animal Production: feed/forage, grazing management, range improvement, rangeland/pasture management
- Education and Training: extension, farmer to farmer, networking, on-farm/ranch research, workshop
- Natural Resources/Environment: biodiversity, carbon sequestration, habitat enhancement, soil stabilization, wildlife
- Production Systems: holistic management
- Soil Management: composting, organic matter, soil analysis, soil microbiology, soil quality/health
- Sustainable Communities: partnerships, sustainability measures
Abstract:
Rangelands in California provide essential ecosystem services such as water purification, wildfire fire prevention, and food and fiber production. Rangelands also serve as the economic base of many rural communities. Because rangelands are rain-irrigated systems, these regions are vulnerable to drought conditions, which are expected to increase in severity due to climate change. Severe droughts pose significant threats to rangelands, including decreased livestock forage production, reduced biodiversity, and soil degradation. These ecological impacts also place significant socio-economic strain on ranchers. Previous initiatives have found that compost amendments provide benefits to soils and forage productivity within agricultural cropping systems, including greater resilience to drought. However, there are potential limitations to applying compost amendments to rangeland soils, and research thus far has demonstrated mixed results, particularly for soil health with key knowledge gaps remaining for the soil microbiome. It is essential to understand the ecological and social implications of compost application before implementing these practices on a large scale. This research examined how compost application impacted soil microbial abundance and community composition on ranches. Soil microbes are essential in key processes that determine soil quality and health; soil health, in turn, impacts forage productivity and improves rangeland resilience to drought conditions. Throughout this project, we worked with ranchers and UCCE advisors to communicate results via on-ranch research and extension workshops. Project outcomes were 1) determining impacts of compost applications on soil microbial ecology, 2) assessing social barriers to adoption, and 3) collaborating and sharing results with stakeholders.
Project objectives:
Our overarching goal for this project was to determine the potential of rangeland compost application as a climate-smart ranching practice to manage soils for increased resilience to prolonged drought, water scarcity, and other environmental challenges in California.
Objective 1: Measure impacts of integrated compost application and clover seeding on soil microbial biomass and community composition
We worked with ranchers and UC Cooperative Extension (UCCE) collaborators who had previously applied compost and clover seeding amendments to their land at a variety of sites. Soil microbes are essential drivers of numerous soil processes (Wagg et al. 2021) and have previously been found to improve resilience to climate change induced drought and prolonged water scarcity (Umezawa et al. 2006). A primary objective of this work was therefore to determine how compost amendments and clover seeding impacted the soil microbiome. We collected soil samples from each site to measure variation in total soil microbial biomass and microbial community composition between sites. We then analyzed these results to assess the potential impacts of compost application practices on the soil microbiome.
Objective 2: Determine potential of compost application to increase drought resilience in rangelands via key soil health metrics
There is substantial evidence that high soil microbial diversity and microbial community composition impact soil health metrics and large-scale ecosystem processes (Wagg et al. 2021). Examining impacts of soil microbial diversity on key soil health metrics could potentially serve as a proxy for drought resilience. We therefore analyzed soil samples collected from all sites for key soil health metrics relevant to improving resilience to drought and increasing water uptake and retention. We measured variation in soil organic matter, soil organic carbon, soil nitrogen, bulk density, and gravimetric water content between sites. This allowed us to determine whether variation in microbial abundance and community composition had an impact on key soil health metrics.
Objective 3: Assess adaptive capacity and potential barriers to adopting compost application as a climate-smart ranching practice
We collaborated with UCCE advisors to create and distribute surveys in order to assess adaptive capacity for implementing compost amendment practices, as well as other potential climate-smart ranching practices (e.g., prescribed burning, strip seeding, livestock species rotation). We built on previously successful initiatives within our lab group using surveys to gauge rancher perspectives on barriers to adopting sustainable ranching practices (Roche et al. 2015). We are currently developing these surveys based on previously successful work applying the four key components of adaptive decision making: information sources, management capacity, goal setting, and previous experience (Lal et al. 2001).
Objective 4: Collaborate with and communicate results to ranchers and key stakeholders
In order to facilitate project collaboration and communicate results to key stakeholders, we leveraged established relationships with UCCE professionals to provide workshops, demonstrations, and resources for ranchers in counties across California. This project included collaborations with UCCE researchers who had partnerships with ranchers who had applied compost and clover seeding to their land or had expressed interest in implementing composting practices on their land.