Evaluation of agricultural byproducts and cover crops as anaerobic soil disinfestation carbon sources for managing a soilborne disease complex in high tunnel tomatoes

Authors: Testen, Anna; ROTONDO, FRANCESCA - The Ohio State University; MILLS, MATTHEW - The Ohio State University; HORVAT, MADELINE - The Ohio State University; MILLER, SALLY - The Ohio State University

Submitted to: Frontiers in Sustainable Food Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2021
Publication Date: 5/13/2021
Citation: Testen, A.L., Rotondo, F., Mills, M.P., Horvat, M.M., Miller, S.A. 2021. Evaluation of agricultural byproducts and cover crops as anaerobic soil disinfestation carbon sources for managing a soilborne disease complex in high tunnel tomatoes. Frontiers in Sustainable Food Systems. 5. Article 645197. https://doi.org/10.3389/fsufs.2021.645197.
DOI: https://doi.org/10.3389/fsufs.2021.645197

Interpretive Summary: In this study, agricultural byproducts (corn gluten meal, distillers dried grains, soybean meal, wheat bran, and whey) and cover crops (buckwheat, cowpea, crimson clover, mustard, oilseed radish, sorghum-sudangrass, white clover, and winter rye) were evaluated as carbon sources to feed soil microbes in anaerobic soil disinfestation for managing a soilborne disease complex in protected culture tomato production in the Midwestern United States. These alternative carbon sources have the potential to improve treatment efficacy and reduce costs and environmental impacts associated with anaerobic soil disinfestation. Several carbon sources were identified that were as effective or more effective than a standard wheat bran ASD treatment. While no cover crop was as effective as a standard wheat midds ASD treatment, several cover crops showed potential efficacy and could be used to reduce amendment rates of conventional ASD carbon sources based on agricultural byproducts. Field trials were conducted with the most promising byproduct carbon sources (soybean meal, wheat midds, and distillers dried grains) but cool soil temperatures limited treatment efficacy. This research will be used to develop better recommendations to Midwestern vegetable producers for applying anaerobic soil disinfestation.

Technical Abstract: Anaerobic soil disinfestation (ASD) is a viable option for disease management in tomato production and reduces damage due to a soilborne disease complex consisting of Pyrenochaeta lycopersici, Colletotrichum coccodes, Verticillium dahliae, and Meloidogyne spp. There are plentiful options for ASD carbon sources using byproducts of Midwestern United States agriculture or cover crops, yet these potential carbon sources have not been evaluated for use in Midwestern settings. Low (10.1 Mg/ha) and high (20.2 Mg/ha) rates of corn gluten meal, distillers dried grains, soybean meal, wheat bran, and whey were evaluated as ASD carbon sources in growth chamber and greenhouse bioassays. Cover crops including buckwheat, cowpea, crimson clover, mustard, oilseed radish, sorghum-sudangrass, white clover, and winter rye were evaluated in similar bioassays with one amendment rate (20.2 Mg/ha). Reducing conditions developed in soils regardless of carbon source or rate. Use of high rates of corn gluten meal, distillers dried grains, soybean meal, and wheat bran led to the lowest levels of root rot severity compared to non-treated controls. The higher rate of any byproduct carbon source was always more effective than the lower rate in reducing root rot severity. Use of both rates of soybean meal or corn gluten meal and the high rate of distillers dried grains or whey led to significant increases in dry root and shoot biomass compared to controls. For cover crops, ASD with crimson clover, sorghum-sudangrass, white clover, or winter rye amendments reduced root rot severity relative to the aerobic control, but not relative to the anaerobic control. Use of cover crops did not significantly impact plant biomass. A subset of three ASD carbon sources (distillers dried grains, soybean meal, and wheat middlings (midds), all 20.2 Mg/ha) were evaluated in five on-farm ASD trials in high tunnels. Soil temperatures were low during the application period, limiting treatment efficacy. Reducing conditions developed in all soils during ASD treatment, and a moderate but significant reduction in root rot severity was observed following ASD with the soybean meal or wheat midds compared to ASD with distillers dried grains. Tomato yield was not significantly affected by ASD treatment.