California Agriculture

California’s Healthy Soils Program (HSP) funds demonstration projects to assess and showcase the impact of HSP practices in California agroecosystems. Here, we summarize findings from seven controlled field trials, each 2 to 3 years in length, and assess the potential of various HSP practices to improve soil health and mitigate climate change in California’s Central Coast vineyards, orchards, cropland, and rangeland. The effect of compost application on soil health and carbon (C) sequestration varied between trials and was impacted by application rate, compost source, and soil properties. Reducing tillage intensity decreased yield in one of three project years and had limited effects on soil health and C sequestration in dryland forage, while no-till did not affect yield or winegrape quality in a biodynamic vineyard. Cover crops in two lemon orchards also showed few effects, likely due to low biomass production of rainfed cover crops during drought. We emphasize the importance of long-term assessments to quantify HSP practice effects and evaluate potential returns on investment across varying soils, environments, and agroecosystems, especially under climate change.