Carbon Sources for Anaerobic Soil Disinfestation in Southern California Strawberry

Anaerobic soil disinfestation (ASD) has been adopted in over 900 ha California strawberry production as an alternative to chemical fumigation. Rice bran, the predominant carbon source for ASD, become increasingly expensive. In 2021–22 and 2022–23 field studies, we evaluated 20–30% lower-priced wheat middlings (Midds) dried distillers’ grain (DDG) at 21,800 kg ha−1 (in 2021) 17,000 2022) sources rice bran. The study was placed Santa Paula, September of each season preparation planting October. Soil air temperatures were 18–26 °C during that time. After incorporation into top 30 cm bed soil, beds reshaped, irrigation drip lines installed covered with totally impermeable film (TIF) prevent gas exchange. Beds irrigated saturate within 48 h after TIF installation. conditions measured redox potential (Eh) sensors 15 depth all plots. Both DDG Midds plots maintained Eh −180 0 mV two ASD weeks, while untreated aerobic 200 400 mV. Permeable bags inocula Macrophomina phaseolina, a lethal soil-borne pathogen strawberry, tubers perennial weed Cyperus esculentus deep initiation retrieved weeks later analyses. Two that, holes cut aerate ‘Victor’ or ‘Fronteras’ bare-root strawberries transplanted them. reduced viable microsclerotia M. phaseolina by 49% first 75 85% both second season. treatments tuber germination C. 86–90% compared one years. Additionally, provided greater sufficiency plant-available nitrogen phosphorus synthetic pre-plant fertilizer improved fruit yields 11–29%. these can suppress pathogens weeds help sustain organic California.