Submitted to: ASHS Centennial Conference
Publication Type: Abstract Only
Publication Acceptance Date: 7/10/2013
Publication Date: N/A
Technical Abstract: Anaerobic soil disinfestation (ASD) is a process in which organic amendments are applied to soil, covered with a polyethylene film, and saturated with water to create conditions conducive for soil bacteria to deplete oxygen levels and generate organic acids in soil. The generation of acids and reduced oxygen availability serve to decrease plant pathogen populations in soil and reduce weed propagules. This method is being evaluated as an alternative to soil fumigants for the production of specialty crops in multiple U.S. states. In the Florida application of ASD, clear polyethylene tarps have been used to allow for soil solarization in addition to generation of anaerobic conditions. Each component in the system appears to have specific effects on different members of the pathogen complex. For example, the addition of poultry litter has a significant effect on fungal plant pathogens, while the water component is important for the control of root-knot nematodes. Control of weeds over multiple cropping seasons required the addition of a carbon source, nitrogen source, and 5 to 10 cm of drip irrigation. Multiple plastic films have been tested for use in this approach, in an attempt to eliminate the need for a solarization period. While anaerobic conditions can be achieved without clear film, nutsedge (Cyperus spp.) control is significantly improved when clear films are used. Previous field trials were conducted in the raised-bed plasticulture vegetable system and currently, test applications are being conducted for flat-field production of cut flowers. It is theorized that facultative anaerobic bacteria, either endemic to the soil or introduced from the soil amendments, play a key role in the treatment. Molecular analysis using length heterogeneity pcr (LH-pcr), cloning, and next generation sequencing have been used to identify bacterial populations that may be essential for ASD treatment.