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United States Department of Agriculture

Agricultural Research Service

Research Project: Alternatives to methyl bromide soil fumigation for vegetable and floriculture production

Location: Subtropical Plant Pathology Research

Title: Status of ASD development for Florida specialty crops

Authors
item Rosskopf, Erin
item Burelle, Nancy
item Butler, David -
item Hong, Jason

Submitted to: Proceedings of International Research Conference on Methyl Bromide Alternatives
Publication Type: Proceedings
Publication Acceptance Date: September 12, 2012
Publication Date: N/A

Interpretive Summary: Anaerobic soil disinfestation (ASD) is a process in which a carbon source (molasses), a nitrogen source (composted broiler litter), and water are added to soil and tarped with an oxygen-impermeable tarp to create conditions conducive for soil bacteria to generate organic acids and deplete the soil of oxygen. The generation of acids and reduced oxygen availability serve to decrease the plant pathogen population in the soil as well as reducing weed propagules. The method is being evaluated as an alternative to the use of soil fumigants for the production of specialty crops in Florida, California, and a number of other east coast vegetable-producing states. In the Florida application of ASD, clear polyethylene tarps have been used to allow for soil solarization in addition to oxygen depletion. Recent work on ASD in Florida has included evaluating this approach for the production of strawberries, cut flowers, and solanaceous vegetables. In field trials conducted for the production of a bell pepper/eggplant double crop, weeds emerging in the planting hole could be reduced using solarization and composted broiler litter, without the addition of significant irrigation water, but this effect did not carry through the next crop. Weed control was significantly better in treatments that included either 2 or 4 inches of irrigation water combined with solarization, composted litter, and molasses. This effect however, was not correlated with high levels of anaerobicity. Consequently, another trial was conducted in which multiple plastic types were evaluated for their effect on generation of anaerobic conditions. While the level of anaerobicity was not impacted by the type of plastic chosen, weed control was significantly better in all plots that were treated with a clear plastic during ASD.

Technical Abstract: Anaerobic soil disinfestation (ASD) is a process in which a carbon source (molasses), a nitrogen source (composted broiler litter), and water are added to soil and tarped with an oxygen-impermeable tarp to create conditions conducive for soil bacteria to generate organic acids and deplete the soil of oxygen. The generation of acids and reduced oxygen availability serve to decrease the plant pathogen population in the soil as well as reducing weed propagules. The method is being evaluated as an alternative to the use of soil fumigants for the production of specialty crops in Florida, California, and a number of other east coast vegetable-producing states. In the Florida application of ASD, clear polyethylene tarps have been used to allow for soil solarization in addition to oxygen depletion. Recent work on ASD in Florida has included evaluating this approach for the production of strawberries, cut flowers, and solanaceous vegetables. In field trials conducted for the production of a bell pepper/eggplant double crop, weeds emerging in the planting hole could be reduced using solarization and composted broiler litter, without the addition of significant irrigation water, but this effect did not carry through the next crop. Weed control was significantly better in treatments that included either 2 or 4 inches of irrigation water combined with solarization, composted litter, and molasses. This effect however, was not correlated with high levels of anaerobicity, measured as Eh. Consequently, another trial was conducted in which multiple plastic types were evaluated for their effect on generation of anaerobic conditions. While the cumulative anaerobicity during treatment was not impacted by the type of plastic chosen, weed control was significantly better in all plots that were treated with a clear plastic during ASD.

Last Modified: 4/23/2014
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