Enzymatic activity of the soil under two forest fragments from Brazil

Abstract

The effects of the monthly variation of the climate and the soil depth (0 - 2 cm and 0 -2 cm) were evaluated on the microbial enzymatic activities from two forest fragments located in Jaboticabal, state of São Paulo, Brazil, in which the covering vegetation was of the Forest and Savannah types and the soil chemical compositions were different. While the dehydrogenase activity did not vary significantly (p>0.05) during the period from October of 2004 to June of 2005, the amylase activity decreased of 96% and the celulase of 9%. This reduction of the activity may be attributed to the litter removal and to the consequent decrease of nutrients in the soil. The activity of these enzymes decreased from the 0 - 2 cm soil layer to the 0 -2 cm. This is supposed to be due to the soil organic matter and fertility decrease. Organic matter and soil moisture contents ranged from 8 to 9% and from 5 to 5% in the Savannah soil and from 6 to 7% and from 8 to 27% in the Forest soil. Soil temperatures oscillated from 9.4 ^oC to 25. ^oC. The small variation of the climatic factors is not supposed to have influenced the variation of the enzymes activities. Additional keywords: amylase; cellulose; dehydrogenase; forest, savannah.