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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Water Management Research » Research » Research Project #441590

Research Project: Linking Soil Carbon Building Practices to Almond Nutritional Quality

Location: Water Management Research

Project Number: 2034-13000-013-006-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Feb 1, 2022
End Date: Jan 31, 2025

The importance of heart-healthy, shelf-stable almonds and almond products became clearer in light of the pandemic. Few studies directly link management for soil health to food nutrition outcomes and to-date no studies have examined soil organic carbon (SOC) and biota, critical components of soil health, and almond nutritional quality. Whole orchard recycling (WOR), i.e. wood chipping excised trees for soil amendment, and cover cropping (CC) both enhance SOC, but have different carbon inputs. We hypothesize that soils under WOR or CC management will have differential slow/stable and fast/labile SOC pools, which will stimulate divergent soil microbial communities. We will evaluate if induced shifts in SOC pools and soil microbiota will impact nutritional and shelf stability quality of the almonds. WOR not only enhances SOC, but also provides a burning alternative, helping growers manage the near-to-complete-phase-out of agricultural burning to be implemented by 2025 in the San Joaquin Valley. Cover crops can enhance soil fertility and water infiltration, provide beneficial insect habitat and weed management, and be an additional revenue if harvested for forage. We will assess two CC treatments, a mixture of beneficial plants (non-forage) and alfalfa, a deep-rooting, nitrogen-fixing forage crop that provides an economic incentive for growers. We will gain fundamental insight into SOC storage under WOR and CC management and potentially link SOC and biological soil health metrics with marketable almond traits. This research helps California almond growers meet consumer demand for healthy and sustainable agricultural products. Project impacts will be based on grower adoption of WOR and CC and on industry shifts in purchasing priorities.

1. Manage research plots to evaluate soil building practices, whole orchard recycling (WOR) and cover cropping (CC), including two cover crop treatments; (i) alfalfa and (ii) a plant species mixture. 2. Model the quality and bioavailability of carbon in soils under WOR and CC and their paired controls using estimated decomposition parameters. 3. Reveal correlations between microbial community characteristics and soil carbon decomposition kinetics and/or indicators of almond nutritional quality. 4. Evaluate quality and yield of forage CC (alfalfa) when intercropped with almonds. 5. Determine if management induced shifts in SOC constituents impact almond shelf life and nutritional quality indicators. 6. Disseminate project results to growers and farm managers, crop advisors, industry supply chain representatives, and consumers.