Rebecca Ryals

Rebecca Ryals

Rebecca Ryals

University of California, Merced | "Assessing climate and soil health benefits of compost application to rangelands with steep slopes"

Merced, CA | rryals@ucmerced.edu

Rebecca is an Assistant Professor of Agroecology at the University of California, Merced. She studies how nutrients and carbon cycle in agroecosystems, and how the management of these cycles contributes to the climate change mitigation and resiliency. Her research focuses on the capture, transformation, and beneficial reuse of organic wastes as resources to rebuild soil carbon and fertility. Previously, she was an Assistant Professor at the University of Hawaii at Manoa and a postdoctoral fellow at Brown University. She completed a Ph.D. at the University of California, Berkeley, M.E.M. at Duke University, and a B.S. at Marywood University.

Session Code: C4

Session Name: Addressing Climate Change

Session Time: Wed, January 27 3:00-4:15 PM EST

Session Description: Climate change may be the existential crisis of our time, but compost figures prominently as part of the solution, especially as part of increasing organic matter in the soil. Learn how applying compost to rangeland in California is working in theory and practice, and how to assess your own impacts.

Presentation Title: Assessing climate and soil health benefits of compost application to rangelands with steep slopes

Presentation Description: Rangelands can be managed for carbon sequestration by the addition of compost. High upfront cost of compost is a major barrier to widespread adoption of this practice. Existing financial incentives to improve soil health through the application of compost require relatively flat topography, excluding rangelands with slopes exceeding 15%, due to concerns over nutrient runoff and lack of local data. To address this barrier, we formed a partnership consisting of carbon farming and organic resources experts at the Alameda Resource Conservation District, StopWaste, USDA Natural Resources Conservation Service, and the University of California, Merced. Through a CDFA Healthy Soils Demonstration grant, our team seeks to generate new insight into how compost can be safely and effectively applied to steep slopes.

We hypothesize that a one-time compost addition to grasslands with steep slopes will increase soil organic matter and soil carbon, increase plant productivity and forage height, have no effect on plant community composition or nutrient runoff. If our findings support our hypotheses, then planners and growers may consider compost application on rangelands with steeper topography, expanding the total acreage upon which improved soil management is considered feasible. This potential expansion of the compost addition practice to steeper slopes will greatly enhance the ability of California’s rangelands to provide carbon sequestration benefits to help meet the state’s ambitious greenhouse gas reduction goals. In this presentation, we will discuss the evolution of our partnership, our study design and results after one year of the three-year experiment, and logistical issues with sourcing and applying compost to steep slopes.