UC Davis

Identifying strategies to rebuild healthy, living soils is critical to not only ameliorating widespread soil degradation resultant from industrial agriculture, but importantly enhancing a multitude of soil ecosystem functions that are fundamental to an Agroecological transition. While many soil health building practices have gained traction, the benefits of these practices are highly dependent on cropping system, co-management practices, climate, and soil type. This is particularly true in California’s almond agroecosystems where a combination of semi- arid climates, no-tillage management, and a historical emphasis on aboveground production components has left soils degraded and strategies to build healthy soil unclear. Therefore, this study tested the use of a regionally-specific survey approach in almond agroecosystems to evaluate relationships between soil health building principles underlying management and soil ecosystem multifunctionality. Specifically, the objectives of this study were to: 1) document the range of soil health building principles used in almond orchard management strategies; 2) measure physical, chemical, and biological indicators of soil ecosystem functioning associated with these strategies; 3) identify linkages between soil health building principles, measured soil indicators, and soil ecosystem functioning in perennial systems; and 4) reflect on the impacts of soil health and principally-based management strategies for more multifunctional agroecosystems.The results of this study indicated that a diverse and stacked application of soil health building principles in practice may be the most effective strategy to enhance multiple soil ecosystem functions simultaneously. The highest performing cluster of orchards utilized animal grazing to manage diverse vegetative understories and had the highest soil organic carbon, total nitrogen, ACE soil protein, available P, soil respiration, and robust and diverse soil communities – resulting in the highest overall multifunctionality score. In contrast, management strategies that reflected minimal soil health building principles (e.g., organic amendments and/or winter living cover) clustered with the conventional management of this region, bare soils that reflect no soil health principles in management. Although more research is needed to investigate the capacity of popular management practices to meaningfully shift soil ecosystem functional indicators in these agroecosystems, this study and its approach offers new insights into the efficacy of a principally-based framework and analysis of management’s impact on soil ecosystems and their functions.