Microbial Communities in Soil Cultivated with Muskmelon under Different Management Systems

ABSTRACT Microorganisms have a fundamental importance in agricultural ecosystems and may be influenced by several factors, including soil management. The aim of this study was to evaluate the effects of cropping systems and soil covers on the microbial community in soil cultivated with muskmelon (Cucumis melo L.). The experiment was conducted in a randomized complete block design with four replications. The treatments were arranged in a split plot design with cropping systems (no-tillage and conventional tillage systems) assigned to the whole plot treatments, while a group of seven soil covers (sunn hemp; millet; sunn hemp + millet; corn + brachiaria; spontaneous vegetation; bare soil; and spontaneous vegetation + polyethylene film) defined the subplot treatments. Total bacteria, sporulating bacteria, fluorescent Pseudomonas sp., and total fungi were quantified at six different times (in fallow soil, at planting of green manures in the soil, when transplanting muskmelon seedlings, and 20, 40, and 60 days after transplanting [DAT]). To determine the quantity of microorganisms, the plate count method was used, with a specific culture medium for the groups. The cultivation of sunn hemp associated with no-tillage at transplanting of muskmelon showed a greater quantity of colony forming units (CFUs) of total bacteria compared to the conventional tillage system. In most treatments, conventional tillage showed greater amounts of sporulating bacteria in relation to no-tillage at the time of transplanting muskmelon and at 40 DAT. The tillage systems and soil cover did not change the total amount of fungi and fluorescent Pseudomonas sp