Effects of Compost and Lime Application on Soil Chemical Properties, Soil Microbial Community, and Fusarium Wilt in Florida-grown Tomatoes

Soils used for vegetable production in Florida are sandy, have low organic matter content and fertility, and can support the growth of soil-borne pathogens. Some growers choose to apply compost as an antagonistic suppression approach to combat soil-borne disease effects on crop yields or to increase organic matter and improve soil fertility. The objective of this on-farm study was to determine the effect of compost and lime on soil chemical properties, the soil microbial community (including Fusarium spp.), and the incidence and severity of fusarium wilt in commercially produced tomato with a history of fusarium wilt. Seasonal trials were conducted in spring and fall of 2010, where soil treatments (composted yard waste and lime) were applied to plots in a randomized complete block design with three replications using a calibrated tractor spreader. Composite soil samples were collected immediately following application of soil treatments, at flowering, and at fruit set and analyzed for soil chemical properties (e.g., organic matter, pH, soil test nutrients, etc.) and soil microbes (e.g., total bacteria, Fusarium oxysporum spp., etc.). Incidence of fusarium wilt was assessed on a periodic basis over the course of tomato production. Data showed that the application of compost and/or lime to soils prior to bedding had no effect on soil pH, EC, or Mehlich 3 nutrients, with the exception of organic matter and Mehlich 3-Mg in fall 2010. Soil organic matter increased when compost was applied at the 30 ton/acre application rate in the fall season, while Mehlich 3 Mg increased when