Microbial Communities in Soil Cultivated with Muskmelon under Different Management Systems

Paula Gracielly Morais Lima Do Nascimento,Rui Sales Júnior,Beatriz Letícia Silva Da Cruz,Andréa Mirne De Macêdo Dantas,Francisco Cláudio Lopes De Freitas,Márcia Michelle De Queiroz Ambrósio

doi:10.1590/18069657rbcs20160130

Paula Gracielly Morais Lima Do Nascimento, Rui Sales Júnior + Show 4 more

Open Access

https://doi.org/10.1590/18069657rbcs20160130

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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.

Highlights

Brazil is one of the main global producers of muskmelon, and the Northeast part of the country is responsible for approximately 95 % of the total fruit production (IBGE, 2013)
The maximum temperature of the soil with the muskmelon showed the highest variation among treatments in the no-tillage system, and the treatments with millet and spontaneous vegetation cover were the ones that offered the lowest temperature along the crop cycle (Figure 1) due to greater shading of the soil in relation to the soil with no plant cover
Within the period from 10 to 18 days after transplanting (DAT) the seedlings, the spontaneous vegetation + polyethylene film treatment in the conventional tillage system was among the treatments with the highest temperatures; in the period from 30 to 46 days after transplanting, this did not occur, due to shading of muskmelon

Summary

Introduction

Brazil is one of the main global producers of muskmelon, and the Northeast part of the country is responsible for approximately 95 % of the total fruit production (IBGE, 2013). Despite the high technology used on muskmelon crops, there is little information on the effects of these soil management practices on the environment. Growth-promoting bacteria of plants, among them sporulating bacteria such as Bacillus spp. and fluorescent Pseudomonas sp., have major agricultural importance since, in addition to favoring plant development, they may act as biological control agents for plant diseases. Several researchers have reported on the importance of these bacteria for development of different crops and induction of resistance to and control of phytopathogens that attack both the shoots and root system of the plant (Teixeira et al, 2005; Araújo and Marchesi, 2009). In turn, may be modified by the management system, due to how the residues of previous crops are deposited and the degree of soil disturbance (Vargas and Scholles, 2000)

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