UC Davis

In an increasingly unstable climate, it is critical to study and quantify water inputs for agriculture. This understanding allows us to optimize what is needed for crop irrigation and secure food production and livelihoods while reducing environmental impacts. Here, we focus on water use in almond orchards—a crop at the center of a $6 billion industry that has long been the focus of scrutiny in California. Regenerative agriculture, a relatively new term used to describe systems that increase soil health, biodiversity, resilience and profitability while reducing greenhouse gas emissions, water use, and pollution, offers a potential solution to modern agriculture’s negative effects. We used eddy covariance, micrometeorological, and soil moisture measurements from 2022 and 2023 to quantify the evapotranspiration of California almond orchards under variable soil and plant management and produce comprehensive estimates of the water footprint of different practices. In an exploratory case study of five almond orchards, we find that there is little difference between evapotranspiration at regenerative and conventional sites in winter months, and that regenerative sites have similar or slightly lower evapotranspiration during the growing season. Yield normalized by cumulative evapotranspiration during the growing season showed decreasing water use efficiency with increasing regenerative practices across studied orchards; however, due to data limitations, these findings require more supporting research. Soil moisture did not appear to be related to whether orchards employed conventional or regenerative management practices, although higher infiltration rates of winter precipitation were observed in orchards with cover crops. These findings indicate that, in California’s Central Valley, regenerative management practices such as cover cropping and livestock integration may not require additional water use in orchards. While more research is needed into the effects of management on yield and potential water stress, our subset of evapotranspiration data suggests shifting almond farming practices towards regenerative management might allow low-cost improvements in water infiltration, soil health, nutrient cycling, and pest suppression, without increasing the water use footprint of agriculture.