The Tree-Crop Remote Sensing of Evapotranspiration eXperiment (T-REX): Exploring Smart-Agricultural Practices for Sustainable Water Management and Climate Mitigation

Aridification trends in the Western United States of America threaten the productivity of one of the world’s most fertile agricultural regions: California’s San Joaquin Valley. During the last decade, historically severe droughts led to unprecedented water conflicts. Under projected changes in climate, droughts of increased severity and duration will exacerbate this situation. California produces 80% of the world’s almonds, which require consistent water supplies for irrigation. In response to these challenges, almond growers and organizations are considering alternative management strategies to save water and mitigate climate change. The Tree-crop Remote sensing of Evapotranspiration eXperiment (T-REX) aims to evaluate these water and orchard management opportunities to maximize water use efficiency and carbon sequestration in almonds and other woody perennial tree crops. The project combines satellite imagery, remotely piloted aerial systems, and proximal sensing technologies to retrieve critical variables used to model surface fluxes and biophysical properties to advance our understanding of how management strategies regulate water-carbon relationships in tree-perennial agroecosystems. A 10% decrease in almond orchard irrigation across the state equates to the average annual residential water use of 2.2 million California households. From a carbon perspective, almond orchards could sequester ~8% of the state’s current greenhouse gas emissions by transitioning toward climate-smart practices. As such, the almond industry is uniquely positioned to curb water use and mitigate climate change while continuing to sustain family growers and agricultural workers economically. California growers are beginning to implement climate-smart agricultural practices such as cover crops, regulated deficit irrigation, no-to-moderate tilling, and organic fertilizers to provide ecosystem services from food-productive working land. We discuss novel micrometeorological and remote sensing and modeling approaches to investigate water, carbon, and other greenhouse gases fluxes over a wide range of conventional-to-climate-smart management practices.