Structure and composition of bacterial and fungal community in soil under soybean monoculture in the Brazilian Cerrado

Abstract

Soybean is the most important oilseed cultivated in the world and Brazil is the second major producer.Expansion of soybean cultivation has direct and indirect impacts on natural habitats of high conservation value, such as the Brazilian savannas (Cerrado). In addition to deforestation, land conversion includes the use of fertilizers and pesticides and can lead to changes in the soil microbial communities. This study evaluated the soil bacterial and fungal communities and the microbial biomass C in a native Cerrado and in a similar no-tillage soybean monoculture area using PCR-DGGE and sequencing of bands. Compared to the native area, microbial biomass C was lower in the soybean area and cluster analysis indicated that the structure of soil microbial communities differed. 16S and 18S rDNA dendrograms analysis did not show differences between row and inter-row samples, but microbial biomass C values were higher in inter-rows during soybean fructification and harvest. The study pointed to different responses and alterations in bacterial and fungal communities due to soil cover changes (fallow x growth period) and crop development. These changes might be related to differences in the pattern of root exudates affecting the soil microbial community. Among the bands chosen for sequencing there was a predominance of actinobacteria, -proteobacteria and ascomycetous divisions. Even under no-tillage management methods, the soil microbial community was affected due to changes in the soil cover and crop development, hence warning of the impacts caused by changes in land use.

Microbial community structure and chemical composition from dark earth in a native archaeological site of the lower Amazon

“…The properties affect the native microbial populations (Bresolin et al, 2010). This study showed small amounts of aluminum in the Amazon soil (Table 3).…”

“…The large variability is due the incorporating of different types and quantities of organic matter (Bissett et al, 2013). Recently, Bresolin et al (2010) observed microbiota present in Brazilian Cerrado soil using DNA analysis by PCR-DGGE. The microbial species isolated were related to Uncultured soil fungus and Uncultured soil bacteria.…”

Estrutura metabólica e genética de comunidades bacterianas em solo de cerrado sob diferentes manejos

“…Diferenças entre as comunidades bacterianas de solo sob vegetação nativa e sob cultivo também foram relatadas por outros autores em solos de cerrado, em Santo Antônio de Goiás, GO (Peixoto et al, 2006), Cristalina, GO (Bresolin et al, 2010) e Planaltina, DF (Peixoto et al, 2010). Segundo Garbeva et al (2004), isso ocorre porque a estrutura das comunidades microbianas é afetada pela estrutura e pela composição da vegetação de cobertura, em virtude da liberação de formas específicas de carbono que podem representar importantes fontes de energia.…”

Isolation and genetic characterization of endophytic and rhizospheric microorganisms from Butia purpurascens Glassman

“…Microorganisms are essential components of ecosystems that participate in 80 to 90% of soil processes, such as the carbon and nitrogen biogeochemical cycles, and are efficient and dynamic indicators of soil quality (Bresolin et al, 2010). Different types of soils and plants possess specific microbial communities, and each plant species is colonized by a different microbial population that is mostly controlled by edaphic variables, especially pH (Berg and Smalla, 2009).…”

“…These new techniques are able to analyze the high complexity of microbial communities, especially because a minority of microbial groups cannot be grown in vitro (Bresolin et al, 2010).…”