Indicadores microbianos e bioquímicos do solo em sítios de vereda, mata seca semidecídua e cerrado sensu stricto

Abstract

The Cerrado has an area of approximately two million square kilometers, being the second largest Brazilian biome, composed of several phytophysiognomies. In its area is found a third of Brazilian biodiversity and about 5% of the world's flora and fauna. Although much of the fauna and flora is known, much remains to be learned about microbiology in soils under native Cerrado vegetation. This knowledge is important to understand the functioning of these threatened environments, providing a database for their monitoring and conservation. The present work evaluated microbial and biochemical indicators of the soil in the dry and rainy season, correlating with physical and chemical aspects under three contrasting native phytophysiognomies of the Cerrado: semideciduous dry forest, cerrado sensu stricto and vereda. The analyzes showed that the microbiology of the soil is different according to the phytophysiognomy, being the path that most differentiated. The hydromorphic nature of the soil of the pathway determines higher levels of organic matter, which explains the greater potential of enzymatic activity and greater respiration when the soil is incubated. In general, the soils of cerrado sensu stricto are the ones that present the lowest values of the microbial and biochemical indicators, and the semideciduous dry forest has intermediate values of these attributes. Thus, a gradient of activity is formed that follows the descending order: vereda, semideciduous dry forest and cerrado sensu stricto. This gradient can be explained by the N content and relative accumulation of organic matter in the soil. Thus, microbial basal respiration, phosphatase, urease and FDA activities were variables indicative of phytophysiognomies, positively related to N content and organic matter, which, in turn, is a consequence of soil moisture content.