Marin Carbon Project Science Papers
WHAT IS THE SOIL CARBON POTENTIAL OF CALIFORNIA ANNUAL GRASSLANDS?
PAPER: “Soil Carbon Pools in California Annual Grassland Ecosystems,” Rangeland Ecology and Management 63 (January 2010):128–136; doi: 10.2111/REM-D-09-00106.1
RESEARCH TEAM: Whendee L. Silver, Rebecca Ryals and Valerie Eviner (Ecosystem Science Division, Department of Environment Science, Policy, and Management, University of California at Berkeley, and Department of Plant Sciences, University of California at Davis)
FINDINGS: When research for MCP began, we wanted to review the existing knowledge on how much carbon (C) is stored in California’s rangeland soils and to see if there were predictable patterns in C storage (i.e., if there were known drivers of patterns across space and time). This paper is a meta-analysis of the literature data on soil C storage in California’s rangelands. Findings indicate that climate is not a good predictor of soil C pools at this scale of resolution and that soil texture (clay content) was a weak correlate of soil C stocks.
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CAN LAND MANAGEMENT ENHANCE SOIL CARBON SEQUESTRATION?
PAPER: “Effects of Organic Matter Amendments on Net Primary Productivity and Greenhouse Gas Emissions in Annual Grasslands,” Ecological Applications 23, no. 1 (2013): 46–59
RESEARCH TEAM: Rebecca Ryals and Whendee L. Silver (Ecosystem Science Division, Department of Environment Science, Policy, and Management, University of California at Berkeley)
FINDINGS: We found that a single (one-time) application of compost doubled forage production (increasing 40–70%) and soil C sequestration (on average 1 ton/hectar) over three years on both coastal (wet) and Sierra Foothill (dry) Mediterranean grassland systems. Compost decomposition provides a slow-release fertilizer to the soils, leading to increases in carbon sequestration and plant production. Net ecosystem C storage increased by 25–70% without including the direct addition of compost C, while compost had no effect on nitrous oxide N20? or CH4 emissions.
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DO RANGELANDS HAVE THE POTENTIAL TO MITIGATE CLIMATE CHANGE?
PAPER: “Impacts of Organic Matter Amendments on Carbon and Nitrogen Dynamics in Grassland Soils,” Soil Biology & Biochemistry 68 (2014): 52e61
RESEARCH TEAM: Rebecca Ryals, Michael Kaiser, Margaret S. Torn, Asmeret Asefaw Berhe, and Whendee L. Silver, (Department of Environmental Science, Policy, and Management, University of California at Berkeley, and School of Natural Sciences, University of California at Merced and Lawrence Berkeley National Laboratory, Earth Sciences Division, Berkeley, )
FINDINGS: This paper showed that compost applications led to an increase in bulk soil C stocks and that an increase in the free light and occluded light C fractions was seen over three years. It is important to note that compost was hand-sorted from soils prior to analysis so the increase in soil C represents mostly new plant derived carbon in the system.
PAPER: “Greenhouse Gas Mitigation Opportunities in California Agriculture, Review of California Rangeland Emissions and Mitigation Potential,” Nicholas Institute for Environmental Policy Solutions
RESEARCH TEAM: Marcia S. DeLonge, Justine J. Owen and Whendee L. Silver (Ecosystem Science Division, Department of Environment Science, Policy, and Management, University of California at Berkeley)
FINDINGS: Management practices that conserve and enhance C storage in rangeland soils and vegetation can help mitigate climate change while enhancing sustainability under future climate scenarios.
DOES COMPOST NEGATIVELY IMPACT PLANT COMMUNITIES?
PAPER: “Grassland Compost Amendments Increase Plant Production without Changing Plant Communities,” Ecosphere 7, no. 3: e01270. 10.1002/ecs2.1270
RESEARCH TEAM: Rebecca Ryals, Valerie T. Eviner, Claudia Stein, Katharine N. Suding and Whendee L. Silver (Department of Environmental Science, Policy, and Management, University of California at Berkeley, and Department of Plant Sciences, University of California at Davis)
FINDINGS: A one-time compost amendment produced large and persistent increases in aboveground biomass for both grassland ecosystems; however, it did not majorly affect species richness or abundance at either grassland site. Overall plant communities were resistant to compost addition. While fertilizer (with inorganic N) has been shown to drive plant invasions and reduce diversity, this study suggests that compost (with organic N) does not drive plant invasions or reduce plant diversity.
WHAT ARE THE GREENHOUSE GAS EMISSIONS FROM THE LIFECYCLE OF COMPOST PRODUCTION AND APPLICATION ON RANGELANDS?
PAPER: “A Lifecycle Model to Evaluate Carbon Sequestration Potential and Greenhouse Gas Dynamics of Managed Grasslands,” Ecosystems 16 (2013): 962–979
RESEARCH TEAM: Marcia S. DeLonge, Rebecca Ryals and Whendee L. Silver (Ecosystem Science Division, Department of Environment Science, Policy, and Management, University of California at Berkeley)
FINDINGS: Composted manure and plant waste produced fewer greenhouse gas emissions than the application of either manure or inorganic nitrogen fertilizer across a broad range of environmental and management conditions. Composting upstream feedstocks like manure and green waste instead of traditional waste management practices results in significant greenhouse gas emissions savings in addition to the sequestration benefits associated with application.
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HOW LONG WILL THE BENEFITS OF COMPOST APPLICATION LAST?
PAPER: “Long-Term Climate Change Mitigation Potential with Organic Matter Management on Grasslands,” Ecological Applications 25, no. 2 (2015): 531–545, 2015 by the Ecological Society of America
RESEARCH TEAM: Melanie D. Hartman, William J. Parton, Marcia S. DeLonge and Whendee L. Silver (Department of Environmental Science, Policy, and Management, University of California at Berkeley, and Natural Resource Ecology Laboratory, Colorado State University, Fort Collins)
FINDINGS: Using field data from previous studies, this paper modeled patterns in C and greenhouse gas dynamics following compost applications on three soil types and over long time periods (100 y). Results indicated that C storage would persist for 30 to 100 years, and that compost application resulted in a long-term increase in C capture and associated nutrient cycling. Few differences were seen when applying small amounts for multiple years versus a single one-time application. Compost with lower C:N ratios led to greater sequestration but higher N2O emissions.
WHAT ROLE COULD MANURE PLAY?
PAPER: “Long-Term Impacts of Manure Amendments on Carbon and Greenhouse Gas Dynamics of Rangelands,” Global Change Biology (2015), doi: 10.1111/gcb.13044
RESEARCH TEAM: Justine J. Owen, Whendee L. Silver, William J. Parton (Department of Environmental Science, Policy, and Management, University of California at Berkeley, and Natural Resource Ecology Laboratory, Colorado State University, Fort Collins)
FINDINGS: Here we explored the long-term implications of manure amendments to rangeland soils. We used data from amended and unamended fields in California to parameterize the DayCent Model to estimate C, nitrogen, and greenhouse gas fluxes. While manure amendments do increase C storage in soils, over time C gains are completely offset by N2O.
PAPER: “Greenhouse Gas Emissions from Dairy Manure Management: A Review of Field-Based Studies” Global Change Biology (2014), doi: 10.1111/gcb.12687
RESEARCH TEAM: Justine J. Owen and Whendee L. Silver (Ecosystem Science Division, Department of Environment Science, Policy, and Management, University of California at Berkeley)
FINDINGS: In this paper, we conducted a meta-analysis on literature regarding global dairy manure emissions and used the results to update the IPCC Tier 2 model for dairy manure emissions. Results showed that the current models underestimate CH4 and N2O from dairy manure management and allowed us to identify gaps in knowledge and opportunities for emissions reduction.
PAPER: Greenhouse Gas Mitigation Opportunities in California Agriculture Review of Emissions and Mitigation Potential of Animal Manure Management and Land Application of Manure Nicholas Institute for Environmental Policy Solutions, February 2014
RESEARCH TEAM: Justine J. Owen, Ermias Kebreab, and Whendee Silver University of California at Berkeley
FINDINGS: Like the above paper we conducted a meta-analysis on literature regarding California dairy manure emissions and used the results to update the IPCC Tier 2 model for dairy manure emissions. This exercise allowed us to identify strategic areas for better manure management that would reduce emissions and enhance compost supply in the state.
