California Air Resources Board

Senate Bill (SB) 1383  (Lara, Chapter 395, Statutes of 2016) established methane emissions reduction targets, including a reduction in statewide methane emissions of 40 percent below 2013 levels by 2030 and an equivalent methane emissions reduction target for the dairy and livestock sector. SB 1383 also requires the California Air Resources Board (CARB), in consultation with the California Department of Food and Agriculture (CDFA), to conduct or consider research on dairy and livestock methane emissions reduction projects, including projects that utilize alternative manure management practices. These practices include solid or dry scrape manure management systems, solid-liquid separation systems, compost-bedded pack barns, and increasing amount of time animals are at pasture. The California Dairy and Livestock Methane Emissions Working Group also recommended research to inform a better understanding of the potential benefits and impacts of alternative manure management practices.  

This study builds on a study funded by CDFA—Benchmarking of Pre-Alternative Manure Management Program—which assessed emissions at six dairy operations prior to the implementation of alternative manure management practices. This follow-up study investigates post implementation emissions measurements at two of those six dairies. It also assesses the accuracy of three different dairy emissions modelling tools at predicting emissions of methane, nitrous oxide, ammonia, and hydrogen sulfide from all six dairies. A companion CARB-funded study—Benchmarking of Post-Alternative Manure Management Program (AMMP) Dairy Emissions and Prediction of Related Long-Term Airshed Effects—assesses the post-implementation emissions measurements at the remaining four dairies.