Increasing Soil Organic Carbon to Mitigate Greenhouse Gases and Increase Climate Resiliency for California
Rising air temperatures are projected to continue to drive up urban, agricultural, and rangeland water use, straining both surface and groundwater resources. Scientific studies have shown that managing farms, ranches, and public lands to increase soil carbon can increase soil waterholding capacity and increase hydrologic benefits such as increased baseflows and aquifer recharge, reduced flooding and erosion, and reduced climate-related water deficits. Coincident improvements in forage and crop yields are also indicated, while simultaneously sequestering carbon, reducing atmospheric greenhouse gases and mitigating climate change. This study was developed to consider the multiple benefits of increasing the organic matter content of soils across California’s working lands.
Climate change poses severe risks to working landscapes in California, including rangelands and croplands, and the ecosystem services they provide. These services include food, habitat, carbon storage, and water supply for urban and rural communities, agriculture and wildlife. A healthy landscape can increase resilience to climate change, increase water quality and net primary productivity, and buffer the impacts of environmental stress leading to forest die-off, wildfire, flood and drought.
Rangelands and croplands, including publicly and privately managed lands, represent a majority of the land base in California. Increasing soil carbon can serve as a climate adaptation strategy due to its documented beneficial effects on soil erodibility, soil-water holding capacity, soil temperature and net primary productivity. Enhancing soil carbon in working lands at large spatial scales has the potential to measurably reduce greenhouse gas levels in the atmosphere, increase the sustainability of working landscapes and ensure the provision of other ecosystem services, including water, food and wildlife habitat. Application of composted urban and agricultural organic waste materials to grasslands and croplands, in conjunction with a suite of strategic land management practices, can remove significant quantities of carbon dioxide (CO2) from the atmosphere and sequester that carbon beneficially in soils and vegetation.
Numerous scientific studies have shown that increasing organic matter (OM) in soils can have multiple benefits, including carbon sequestration and reduction of atmospheric greenhouse gases (GHG)(DeLonge et al., 2014; Ryals and Silver, 2013, DeLonge et al., 2013). Soil management strategies and active management of working lands for enhanced carbon sequestration, such as "carbon farming," have a critical role to play in helping California develop resilience to climate change while simultaneously reducing atmospheric greenhouse gases. "Carbon farming" is a systems approach to land management that involves implementing practices that can improve the rate at which CO2 is removed from the atmosphere and converted to plant material and/or soil organic matter. Carbon farming integrates ecological site assessment and mapping in conservation planning, uses dynamic ecosystem carbon models to predict and measure increases in farm-system terrestrial carbon stocks, and incorporates hydrologic modeling to evaluate potential long-term impacts to on-farm water resources. Benefits of carbon farming include improvement in soil health, increased forage and crop yields, increase in soil-water holding capacity and reduction in total landscape demand for water, carbon sequestration, reduction of atmospheric greenhouse gases (GHG) and diversion of urban and agricultural organic waste from methane-producing anaerobic disposal in landfills and manure lagoons, and from burning.
Water that stays in the watershed can serve to preserve baseflows and riparian systems during low-flow periods and can potentially serve to sustain infiltration to the groundwater system. Figure 1 illustrates the calculation, using a hydrologic model, of a reduction in climatic water deficit (CWD) of 0 to 4.5 inches per year with a 25% increase in soil water-holding capacity (WHC) associated with increased soil OM for the northern Sacramento Valley. This reduction implies greater soil moisture, less irrigation demand, an increase in net primary productivity (NPP, equivalent to actual evapotranspiration), lower fire risk, and increased drought resiliency and carbon capture capacity.
The California Natural Resources Agency (CNRA), which is conducting the California 4th Climate Change Assessment (CCA) for non-energy-related projects, and is seeking new and innovative approaches to increase resilience to climate change, has funded this project. The Berkeley Energy and Climate Institute (BECI) is serving as the administrative office for agreements and reporting.
Objective and Scope
This project will use data generated from published and ongoing field and lab trials to constrain water-balance model estimates of soil moisture and evapotranspiration in order to quantify the potential changes in WHC and carbon sequestration for all rangeland and cropland soils statewide in response to increases in SOM. This approach will rely on current soil properties and calculate maximum potential benefit of increased SOM for all grasslands, pasture and arable lands in California. Limits to soil improvements will be illustrated, as not all of these lands would benefit from increases in SOM (e.g. wetlands, vernal pools, serpentine soils). Additionally, results will be used to estimate the economic value of both no-action and management actions leading to SOM increases, with respect to system hydrology and carbon sequestration for a representative sample of agricultural crops and rangeland types.
Finally, we will identify barriers to, and incentives for, statewide farmland and rangeland carbon storage enhancement within a climate-smart land-use planning framework under current and projected climate and land-use scenarios.
The development of state-of-the-art climate and hydrological surfaces for baseline conditions and future climates at a fine spatial scale will serve to inform other California 4th Climate Change Assessment projects. Significant integration with Project 2B submittal "Soil water dynamics, carbon sequestration, and greenhouse gas mitigation potential of using composted manure and food waste on California's rangelands" will provide leveraged opportunities for further understanding and model validation.
Relevance and Benefits
The proposed work directly addresses several aspects of the USGS Science Strategy for the Decade, 2007-2017 (U.S. Geological Survey, 2007), specifically "Understanding Ecosystems and Predicting Ecosystem Change, Climate Variability and Change." In addition to uncertainties about water supply, increases in landscape stress and wildfires are becoming more prevalent in California as a result of changing climate. Land and resource managers are seeking understanding as to the most scientifically defensible strategies for successful water-supply and resource management. This study will provide refined tools and information to manage and prioritize landscapes to increase resilience to climate change.
Below are other science projects associated with this project.
Basin Characterization Model (BCM)
Rising air temperatures are projected to continue to drive up urban, agricultural, and rangeland water use, straining both surface and groundwater resources. Scientific studies have shown that managing farms, ranches, and public lands to increase soil carbon can increase soil waterholding capacity and increase hydrologic benefits such as increased baseflows and aquifer recharge, reduced flooding and erosion, and reduced climate-related water deficits. Coincident improvements in forage and crop yields are also indicated, while simultaneously sequestering carbon, reducing atmospheric greenhouse gases and mitigating climate change. This study was developed to consider the multiple benefits of increasing the organic matter content of soils across California’s working lands.
Climate change poses severe risks to working landscapes in California, including rangelands and croplands, and the ecosystem services they provide. These services include food, habitat, carbon storage, and water supply for urban and rural communities, agriculture and wildlife. A healthy landscape can increase resilience to climate change, increase water quality and net primary productivity, and buffer the impacts of environmental stress leading to forest die-off, wildfire, flood and drought.
Rangelands and croplands, including publicly and privately managed lands, represent a majority of the land base in California. Increasing soil carbon can serve as a climate adaptation strategy due to its documented beneficial effects on soil erodibility, soil-water holding capacity, soil temperature and net primary productivity. Enhancing soil carbon in working lands at large spatial scales has the potential to measurably reduce greenhouse gas levels in the atmosphere, increase the sustainability of working landscapes and ensure the provision of other ecosystem services, including water, food and wildlife habitat. Application of composted urban and agricultural organic waste materials to grasslands and croplands, in conjunction with a suite of strategic land management practices, can remove significant quantities of carbon dioxide (CO2) from the atmosphere and sequester that carbon beneficially in soils and vegetation.
Numerous scientific studies have shown that increasing organic matter (OM) in soils can have multiple benefits, including carbon sequestration and reduction of atmospheric greenhouse gases (GHG)(DeLonge et al., 2014; Ryals and Silver, 2013, DeLonge et al., 2013). Soil management strategies and active management of working lands for enhanced carbon sequestration, such as "carbon farming," have a critical role to play in helping California develop resilience to climate change while simultaneously reducing atmospheric greenhouse gases. "Carbon farming" is a systems approach to land management that involves implementing practices that can improve the rate at which CO2 is removed from the atmosphere and converted to plant material and/or soil organic matter. Carbon farming integrates ecological site assessment and mapping in conservation planning, uses dynamic ecosystem carbon models to predict and measure increases in farm-system terrestrial carbon stocks, and incorporates hydrologic modeling to evaluate potential long-term impacts to on-farm water resources. Benefits of carbon farming include improvement in soil health, increased forage and crop yields, increase in soil-water holding capacity and reduction in total landscape demand for water, carbon sequestration, reduction of atmospheric greenhouse gases (GHG) and diversion of urban and agricultural organic waste from methane-producing anaerobic disposal in landfills and manure lagoons, and from burning.
Water that stays in the watershed can serve to preserve baseflows and riparian systems during low-flow periods and can potentially serve to sustain infiltration to the groundwater system. Figure 1 illustrates the calculation, using a hydrologic model, of a reduction in climatic water deficit (CWD) of 0 to 4.5 inches per year with a 25% increase in soil water-holding capacity (WHC) associated with increased soil OM for the northern Sacramento Valley. This reduction implies greater soil moisture, less irrigation demand, an increase in net primary productivity (NPP, equivalent to actual evapotranspiration), lower fire risk, and increased drought resiliency and carbon capture capacity.
The California Natural Resources Agency (CNRA), which is conducting the California 4th Climate Change Assessment (CCA) for non-energy-related projects, and is seeking new and innovative approaches to increase resilience to climate change, has funded this project. The Berkeley Energy and Climate Institute (BECI) is serving as the administrative office for agreements and reporting.
Objective and Scope
This project will use data generated from published and ongoing field and lab trials to constrain water-balance model estimates of soil moisture and evapotranspiration in order to quantify the potential changes in WHC and carbon sequestration for all rangeland and cropland soils statewide in response to increases in SOM. This approach will rely on current soil properties and calculate maximum potential benefit of increased SOM for all grasslands, pasture and arable lands in California. Limits to soil improvements will be illustrated, as not all of these lands would benefit from increases in SOM (e.g. wetlands, vernal pools, serpentine soils). Additionally, results will be used to estimate the economic value of both no-action and management actions leading to SOM increases, with respect to system hydrology and carbon sequestration for a representative sample of agricultural crops and rangeland types.
Finally, we will identify barriers to, and incentives for, statewide farmland and rangeland carbon storage enhancement within a climate-smart land-use planning framework under current and projected climate and land-use scenarios.
The development of state-of-the-art climate and hydrological surfaces for baseline conditions and future climates at a fine spatial scale will serve to inform other California 4th Climate Change Assessment projects. Significant integration with Project 2B submittal "Soil water dynamics, carbon sequestration, and greenhouse gas mitigation potential of using composted manure and food waste on California's rangelands" will provide leveraged opportunities for further understanding and model validation.
Relevance and Benefits
The proposed work directly addresses several aspects of the USGS Science Strategy for the Decade, 2007-2017 (U.S. Geological Survey, 2007), specifically "Understanding Ecosystems and Predicting Ecosystem Change, Climate Variability and Change." In addition to uncertainties about water supply, increases in landscape stress and wildfires are becoming more prevalent in California as a result of changing climate. Land and resource managers are seeking understanding as to the most scientifically defensible strategies for successful water-supply and resource management. This study will provide refined tools and information to manage and prioritize landscapes to increase resilience to climate change.
Below are other science projects associated with this project.