Evaluating Benefits of Cover Crops on Yuma Soil Health

Soil health is the essential capacity of a soil to function as a living ecosystem that sustains plants, animals, and humans. Soil health conservation is a top research priority identified by Yuma growers, but they currently lack data for best management practices to improve soil health. One potential beneficial practice is planting cover crops during the spring and summer fallow period when vegetables can’t be grown, instead of leaving soils bare. Cover crops have been shown to improve physical, chemical, and biological components of soil health in wetter climates, but there’s no evidence from hot, hyper-arid regions like Yuma. Improving soil health may also help fend off Fusarium wilt. Therefore, this project will address two urgent questions: (1) Does cover cropping improve Yuma soil health? (2) Which currently used cover crop improves soil health more—cotton or Sudan grass? In a field with the same winter vegetable and soil type, the research team will quantify benefits of cotton and Sudan grass compared to fallow areas using a suite of soil health metrics. Soils will be evaluated in July 2020 after cover crops are incorporated but before beds are prepared for vegetables. Project outcomes will be: (1) a methodology for Yuma soil health assessment, (2) a scientific publication advancing knowledge of cover crop effects on desert soil health, and (3) preliminary results to increase the competitiveness of multiple $500k+ grant proposals for future studies of novel cover crops, long-term trends, and additional management practices to conserve and enhance soil health in desert agriculture.