BIOMASS AND MICROBIAL ACTIVITY IN SOILS UNDER DIFFERENT CROPPING SYSTEMS IN THE SÃO FRANCISCO VALLEY

The inadequate management of the soil can intensify the degradation and change the soil structure, providing a significant increase in gas emission, affecting mainly the dynamics of CO2emission, besides favoring the increase of the mineralization rate of the soil organic matter and reduction of microorganisms that act as biological indicators. In this context, the objective of this work was to evaluate the changes on soil biomass and microbial activity, due to the implementation of viticulture, mangiculture and forage crops in areas of the Caatinga Biome. The experiment was carried out in Petrolina-PE. Soil samples were collected at 0-5 and 5-10 cm depth, in areas cultivated with grapevine (in different phenological stages), mango, elephant grass and caatinga. The following were analyzed; pH, P, K+, Na+, Ca++, Mg++,total organic carbon (TOC), bulk density, particle density, total porosity, microbial biomass carbon (MBC), basal respiration and metabolic quotient. The soil chemical and biological properties are affected by the removal of natural vegetation. The managed areas presented high CO2emissions per unit of soil microbial biomass (SMB), favoring high carbon losses. The phenological phase of the vine in which the leaf mass is reduced, influenced the SMB.