Matter of Trust is proud to be one of the sponsors of this program and Dr. Whendee Silver’s important work.

The food system accounts for more than one third of global greenhouse gas emissions. Agricultural land use and waste combined are the largest greenhouse gas emitters in the food system. The Silver Lab is working to minimize emissions from agriculture and the waste stream by determining the carbon and greenhouse gas dynamics of composting urban and agricultural waste and studying the carbon sequestration potential of applying compost to grassland and cropland. Results from ongoing field experiments show that a single application of compost can increase the capacity of rangeland ecosystems to store carbon, while enhancing other ecosystem services including forage production and soil water holding capacity. Field and modeling data suggest that compost amendments can lead to long-term soil carbon storage on the scale of decades to a century. Using lifecycle assessment modeling, we have determined that composting high emitting organic wastes followed by land application leads to net negative carbon fluxes – i.e. carbon dioxide removal from the atmosphere. If scaled to 5 % of California’s rangelands, this practice could lead to an offset of approximately 28 MMt CO₂-eq, or nearly one year of emissions from the state’s agriculture and forestry sectors.

The Silver Lab is also exploring the use of waste rock for carbon dioxide removal via enhanced weathering. Preliminary field trials are underway using rock dust alone and in combination with compost and biochar. Our work in high emitting agricultural systems includes dairy farming and peatland agriculture. In these ecosystems we are exploring ways in which irrigation and amendment management can lower emissions and increase soil carbon sequestration while enhancing ecosystem sustainability. Our goals are to rigorously assess the carbon and greenhouse gas dynamics of working lands and determine the potential for them to contribute to climate change mitigation. More information can be found at https://nature.berkeley.edu/silverlab/.