S15 - Session P1 - Managing for multifunctionality: exploring the potential of healthy soils to support ecological functions in orchard agroecosystems

Authors: Amelie Gaudin *, Krista Marshall , Katherine Jarvis-Shean, Amanda Hodson , Timothy Bowles

Healthy soil ecosystems are a central component of Agroecological models as many of the biologically-driven functions that promote multifunctionality occur belowground. In contrast to prescriptive, synthetic input-based and extractive management practices, strategic implementation of Agroecological principles can help regenerate the resources and habitats necessary to promote healthy soil ecosystems and high levels of functioning. While there are well-defined principles for building healthy soil, the context specific nature of Agroecology requires that strategies be reflective of the unique socio-ecological characteristics of regionally-based cropping system. While there is an increasing body of empirical evidence showing the functional potential of healthy soil, strategies to enhance these functions and their benefits have yet to be fully captured in California orchard agroecosystems. This is especially urgent as California's agricultural landscapes, including more than 2 million acres of orchard agroecosystems, grapples with widespread soil degradation across ecologically fragile watersheds. The objectives of this study were to: 1) document soil health building principles in working orchard productions, 2) measure biochemical and physical indicators of soil ecosystem functions, and 3) explore the relationships between measured indicators, soil ecosystem functioning, and principally-based Agroecological management. A soil survey approach was used within a restricted pedologic and climatologic region to quantify a range of indicators in 23 mature orchards that spanned a gradient of individual and stacked soil health building principles. We documented a wide range of context-specific, innovative, and effective soil health building strategies used by growers. Results highlight the potential of these orchards systems to build healthy soils and that stacking principles are key to bolstering soil ecosystem functioning. This study and its results are being used to develop collaborative, interdisciplinary research projects to continue exploring the role of Agroecological management in building multifunctional orchard agroecosystems across the semi-arid irrigated agricultural landscapes of California.