Activity of soil microbial biomass altered by land use in the southwestern Amazon

• Published in: Bragantia 2016-03, Vol.75 (1), p.79-86
• Main Authors: Mazzetto, André Mancebo, Cerri, Carlos Eduardo Pellegrino, Feigl, Brigitte Josefine, Cerri, Carlos Clemente
• Format: Article
• Language: English
• Subjects: AGRICULTURE, MULTIDISCIPLINARY
• ISSN: 0006-8705; 1678-4499; 1678-4499
• DOI: 10.1590/1678-4499.066

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. RESUMO A demanda crescente de alimentos gera problemas ambientais, principalmente devido à remoção das coberturas vegetais nativas para a expansão da agricultura no Brasil. Essas alterações no uso da terra acarretam mudanças na dinâmica da matéria orgânica do solo. Os micro-organismos representam a maior diversidade biológica e fisiológica do solo, além de serem responsáveis por mais de 95% dos processos de decomposição e ciclagem de nutrientes. O objetivo deste trabalho foi verificar se há diferenciação dos padrões de atividade da biomassa microbiana dos solos sob as diferentes vegetações naturais, pastagens em uso e sistemas agrícolas recém-implantados. A área de abrangência desta pesquisa corresponde aos Estados de Rondônia e Mato Grosso. Foi realizada a análise de variável canônica de atributos físicos, químicos e microbiológicos de cada ecorregião e uso da terra, buscando evidenciar os padrões e as variáveis que os diferenciam. As áreas nativas apresentaram padrões distintos na din