Comunidade bacteriana, atributos do solo e fluxo de gases em solo sob Cerrado e cana-de-açúcar / Bacterial community, soil properties and gas fluxes in a soil under Cerrado and sugarcane

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

The sugarcane crop plays an important role on Brazilian economy, and is passing through an expansion process concentrated mainly on the Cerrado (savannah) biome (Middle West region of Brazil). In order to understand the influence of sugarcane cultivation and management on soil chemical, physical and biological properties, we studied two sugarcane areas, with (burnt cane) and without burning before harvest (green cane), and a fragment with native vegetation located at the municipality of Porteirão (Goias state, Brazil) (17 ° 55 35 S "N 50 ° 0836" W). We analyzed the structure of total (16S rDNA) and functional (nitrifying and denitrifying microorganisms) soil bacterial community, as well as some physical and chemical factors. Significant changes were observed in several attributes. The management with and without burning responded differently to soil changes, resulting on areas with distinct properties. The changes observed in at least one of the treatments were mainly related to the following soil properties: density and temperature increase, reduction of aggregation, C and N levels, enrichment of 13C and 15N values, denitrification potential reduction, qualitative and quantitative changes in mineral N content and on net mineralization and net nitrification of N. Soil greenhouse gases flows have undergone little change in level of treatment, and the flow of CH4 and N2O where very low in studied areas. There were significant changes on structure of total, nitrifying and denitrifying bacteria community, but the groups responded differently to soil changes. The direction of changes in total soil bacterial community structure where given by the interaction of physical-chemical factors together, especially those related to soil aggregation, mineralogy, fertility and temperature. But changes in the structure of functional groups, were not explained only by that standard, and showed great importance of biological interactions on community structure. The flow of greenhouse gases from the soil, the denitrification potential and cycling of C and N in general, correlated with changes in total and/or functional bacterial communities, showing the influence of the microorganisms in these factors. However, the net rates of mineralization and nitrification of soil N did not correlate, suggesting that others factors were involved.

ASSUNTO(S)

soil microbiota cerrado land use change mudança no uso do solo microbiota do solo cerrado

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