Influência da variação sazonal, sobre os atributos químicos e biológicos do solo nos sítios do LBA e PPBIO em Caxiuanã/PA, Amazônia Oriental

Abstract

Several environmental factors, such as pH, temperature and soil moisture influence the density and the activity of microorganisms. It is possible that the balance of the biosphere is being changed by global changes of natural origin and influencing of human activities environmental factors that determine the behavior of the soil phase microbiota. In order to verify the influence of these changes, the present study has been developed in the area of the ESECAFLOR experiment, which simulates the occurrence of extreme phenomena such as the El Niño and the area of the PPBio Programme (Primary Forest area), which aims to study the biodiversity of the Amazon, being last used for comparative purposes (witness). The soil samples for chemical analysis, physical and biological properties were collected into the depths: 00 – 05, 05 -10, 10-20 and 20 – 30 cm in seasonal Transition periods, Rainy and Less rainy. It was also determined the temperature of the soil under the same depths. The methods used were described by Embrapa (1997), Clark (1965), Gerhardt (1994), Yang et al. (1998) and Keeney (1982). The treatment of data and the statistical tests (ANOVA: two criterion, Tukey test and simple Linear Correlation) were performed by means of statistical programme Bioestat 5.0. The highest levels of macro and micro nutrients were found in natural primary forest area (PPBio). The greatest values of colony-forming units of Colonies (196 x 10 4 UFC/g the soil and 124 x 10 2 UFC/g the soil) for the population of bacteria and fungi, respectively, were also identified in the area of PPBio and rainy and the intermediary periods, respectively. Was identified significant differences between the data obtained for both areas and also significant difference of each area in relation to seasonal periods and the depths studied. The area that changed human (ESECAFLOR) presented the lowest levels for macro and micronutrients, demonstrating the influence of the deletion process of rainwater in the availability of these elements in the soil.