Informing agricultural emissions management
Analysis of the costs and benefits of switching to paddy rice production suggests that farmers could increase profits while reducing greenhouse gas emissions.
Drainage of organic soils for agriculture has resulted in widespread soil subsidence (sinkage relative to surrounding areas) and increased greenhouse gas emissions. The Sacramento-San Joaquin Delta in California, once an expansive wetland, was drained and converted to agricultural production in the mid-1800s, and has since experienced subsidence rates that are among the highest in the world. Upland crops there are grown on rapidly sinking soils that emit large amounts of carbon to the atmosphere as previously flooded soils are exposed to air and begin to decompose. Pumping costs and associated saltwater intrusion risks are escalating, and drained agriculture in the Delta is considered unsustainable in the long term1.
A six-year project supported by USDA National Institute for Food and Agriculture, NASA, and DOE examined the costs and benefits of switching to flooded paddy rice production in the area, and the possibility of increasing resilience to climate risk and reducing greenhouse gas emissions while maintaining profits for farmers2. The project has provided information to farmers in the region on the on the economic viability of transitioning to rice and the potential to contribute to and benefit from California’s greenhouse gas emissions reduction goals. Results from the project suggests that converting drained agricultural peat soils to flooded land use types can help reduce or reverse soil subsidence and reduce greenhouse gas emissions while potentially increasing profits to farmers3.
1 Knox, S. H., C. Sturtevant, J. H. Matthes, L. Koteen, J. Verfaillie, and D. Baldocchi. 2015. Agricultural peatland restoration: Effects of land-use change on greenhouse gas (CO2 and CH4) fluxes in the Sacramento-San Joaquin Delta. Global Change Biology 21, 750–765. https://doi.org/10.1111/gcb.12745
2 Ye, R. and W.R. Horwath. 2016. Nitrous oxide uptake in rewetted wetlands with contrasting soil organic carbon contents. Soil Biology and Biochemistry 100, 110–117. https://doi.org/10.1016/j.soilbio.2016.06.009
3 Deverel, Steven; Jacobs, Paul; Lucero, Christina; Dore, Sabina; Kelsey, T. Rodd. 2017. Implications for Greenhouse Gas Emission Reductions and Economics of a Changing Agricultural Mosaic in the Sacramento-San Joaquin Delta. San Francisco Estuary and Watershed Science, 15 (3).