Masters Theses

Date of Award

12-2012

Degree Type

Thesis

Degree Name

Master of Science

Major

Plant Sciences

Major Professor

David M. Butler

Committee Members

Annette L. Wszelaki, Bonnie H. Ownley

Abstract

Anaerobic soil disinfestation (ASD) is a non-chemical, pre-plant soil treatment recently developed for control of pests such as soilborne plant pathogens, plant-parasitic nematodes, and weeds in specialty crop systems. Soil treatment by ASD includes incorporating a labile carbon (C) source, tarping with plastic, and irrigation of the topsoil to saturation to facilitate the development of strongly anaerobic soil conditions driven by soil microbes. Processes occurring during the anaerobic decomposition of the added C source have been reported control plant pests. The goal of this project was to evaluate and adapt the ASD procedure to environmental conditions and production systems in Tennessee and examine the potential for on-farm implementation. To meet this goal, study objectives were to 1) evaluate both cover crop and off-farm C inputs for ASD treatment for production of bell pepper and tomato in a research station field experiment, 2) evaluate cool-season cover crop and off-farm inputs as C sources for ASD treatment in a growth chamber pot experiment with introduced sclerotia of Sclerotium rolfsii and propagules of key weed species, and 3) demonstrate and evaluate on-farm implementation of ASD on a commercial tomato farm. Data collection included soil properties, pest assessment, and crop performance. Results indicated no differences in total marketable fruit yields between treatments in any of the studies, likely due to low disease pressure, plant-parasitic nematode populations, and weed populations apparent in all studies. Accumulation of anaerobic soil conditions generally did not differ among treatments, possibly due to the generally low C amendment rates and the soil properties in study locations. Treatment by ASD did impact a number of soil properties, including levels if inorganic soil nitrogen, which will need to be addressed when developing best management practices for ASD implementation. Additional studies are needed on sites with high existing pest pressure to further evaluate the feasibility of ASD for commercial production systems.

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