Submitted to: Microbial Ecology International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2008
Publication Date: 8/31/2008
Citation: Buyer, J.S., Zasada, I.A., Roberts, D.P., Teasdale, J.R. 2008. Effects of cover cropping on soil and rhizosphere microbial community structure in tomato production systems [abstract]. Microbial Ecology International Symposium. p. 51.
Technical Abstract: Black polyethylene film is frequently used in vegetable farming systems to promote rapid warming of the soil in spring, conserve soil moisture, and suppress weeds. Alternative systems have been developed using cover cropping with legumes to provide a weed-suppressive mulch while also fixing nitrogen. In a previous study (Carrera et al., (2007) Applied Soil Ecology 37:247-255) we found that soil microbial community structure was distinctly different under black polyethylene film than under hairy vetch cover crops in tomato production systems. In order to determine the major factors affecting microbial community structure in these systems we set up a replicated field experiment with nine treatments: bare soil, black polyethylene, white polyethylene, hairy vetch cover crop, hairy vetch above-ground biomass, hairy vetch below-ground biomass, rye cover crop, rye above-ground biomass, and rye below-ground biomass. Soil temperature and moisture were monitored. Tomato rhizosphere and bulk soil were sampled and analyzed for phospholipid fatty acids (PLFA). The black polyethylene treatment had the highest soil temperatures, while both polyethylene treatments had the highest soil moisture levels. Soil and rhizosphere microbial community structure were significantly different for black and white polyethylene compared to all other treatments, suggesting that soil temperature was not a major factor while soil moisture may have been. Total PLFA, and the amount of each PLFA biomarker, were greater in cover-cropped treatments than in polyethylene and bare soil treatments. We conclude that the effects of vetch and rye cover crops on microbial communities were primarily due to vetch shoots and rye roots, respectively.