Abstract
ABSTRACT The increasing demand for food creates environmental problems, mainly due to the removal of native vegetation cover for agriculture expansion in Brazil. These changes in land use lead to changes in the soil organic matter dynamics. Microorganisms represent the most biological and physiological diversity in soil, as well as are responsible for more than 95% of the decomposition and nutrient cycling processes. The objective in this research was to check if there is difference of patterns in activity of soil microbial biomass under varied natural vegetation, pastures in use and agricultural systems recently established. The area covered by this study corresponds to the states of Rondônia and Mato Grosso. Canonical variate analysis was used in physical, chemical and microbiological factors in each ecoregion and land use, looking for patterns and variables that can differentiate them. The native areas showed distinct patterns in the dynamics of microbiological attributes mainly related to the amount of litter in each biome studied. For the disturbed areas, there were similar results between pastures and native areas, significantly different from the results obtained in agricultural areas, which, due to differences in management and kind of cultures analyzed, showed a great variability in the final result. The results support the recommendation for use of microbiological attributes as indicators of land use change, combined with chemical and physical factors of the soil.
Highlights
MATERIAL AND METHODSThe growing demand for food, fiber and biofuel creates various environmental problems, mainly caused by the disorderly occupation of the largest agricultural border in the world, that between the Amazon Forest and the Cerrado of Central Brazil (Borlaug 2002)
There was a great similarity between the values of native areas and pastures, with significant differences from agricultural areas (Table 1)
The relationship between carbon immobilized in the microbial biomass and total soil organic carbon followed the same trend, i.e. 25% higher in pasture areas
Summary
The growing demand for food, fiber and biofuel creates various environmental problems, mainly caused by the disorderly occupation of the largest agricultural border in the world, that between the Amazon Forest and the Cerrado of Central Brazil (Borlaug 2002). The microbial biomass is the living and active part of the soil and can indicate changes in the amount of nutrients due to changes in land use (Brookes 2001). Microbial biomass fluctuates to reach a new equilibrium (Powlson et al 1987). In this way, the demand for rapid and reliable indicators to detect changes in soil quality has been continuously growing, mainly those based on microorganisms (Anderson 2003; Ananyeva et al 2008)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
