Effect of compost tea on plant growth performance and the fate of microbial communities in soil

Valdes, Elise Claire
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Compost tea is a popular amendment used to improve soil quality and to control soil-borne diseases in plants. With proper brewing, compost tea contains many of the beneficial microbes and nutrients of compost, but is more easily applied to plants. The purpose of this study was to (i) analyze the fate of microbial communities in spent mushroom substrate compost tea applied to soil microcosms planted with corn, and (ii) determine if growth of corn is influenced by specific constituents from compost tea, including microbes only, nutrients only, or a combination of both (i.e. the complete compost tea). Two trials were performed, one with anaerobic soil conditions and a second with aerobic soil conditions. Bacteria and Eukarya were quantified over the 30 days with sampling events on days 0, 1, 2, 5, 10, 20, and 30, as were plant growth performance characteristics like root and sprout length or their biomass. Results demonstrated a significant drop (70-90%) in abundance of microbes after application of compost tea, without recovery during the 30-day incubation period. Plant growth performance characteristics were not statistically significantly different for corn on soil receiving compost tea or separated components (i.e. microbes or nutrients) only, or a water control. While these results cannot support assumptions on beneficial effects of compost tea on plant growth performance and microbial communities in soil after application, further scientific research should consider long-term studies with different plant species and soils to further investigate potential beneficial effects of compost tea.
Compost tea, Microbes
Valdes, E. C. (2015). <i>Effect of compost tea on plant growth performance and the fate of microbial communities in soil</i> (Unpublished thesis). Texas State University, San Marcos, Texas.