Avaliação de Propriedades Físicas dos Solos e da Macrofauna Edáfica em Áreas Submetidas a Manejo Florestal de Vegetação Nativa na Chapada do Araripe

Abstract

Anthropization of native forests causes imbalances of ecosystems, changing the physical, chemical and biological properties of soil. Among those imbalances, we can mention the reduction in groundwater recharge. Springs or the slope of the Araripe plateau show signification reduction in discharges, and deforestation, with its effects on soil structure and on the recharge to aquifers, may be the cause. For the Araripe plateau there are forest management plans aiming at regional economic development; but without monitoring those plans can cause soil damage. In this study we evaluated the following parameters of the soil macrofauna a forest management unit of native vegetation on the Araripe plateau and compared them to the parameters in a preserved area: levels of organic matter and soil moisture, infiltration capacity, soil resistance to penetration, macro and micro porosity and density of individuals.of soil macrofauna. Soil samples collected were sorted into three groups of quantitatively similar organic matter, so that the group having the highest value represented preserved forest (Group 1) and the other groups represented managed areas (Groups 2 and 3). The plots already exploited (Group 3) presented lower organic matter content than those under exploitation, those not yet exploited and that of legal reserve area (Group 2). Group 1 presented a higher moisture content and infiltration capacity. Even in the dry period, the moisture of this group was higher than that of the others in the rainy season, indicating that the organic matter maintains moisture. The infiltration rate in Group 1 presented a lower coefficient of variation, indicating soils of homogeneous infiltration; Group 2 presented an intermediate infiltration variation, indicating soils under restoration and tending to uniformity of infiltration; and Group 3 showed a high level of infiltration rate variation, indicating soils with heterogeneous infiltration. In the 0 to 40 cm layer. Soils from Group 1 had a lower resistance to penetration than those from Groups 2 and 3. However, at depths from 40 to 60 cm, soils did not differ significantly, indicating a low influence of anthropogenic activity in this profile. The macroporosity presented a higher value for Group 1, indicating that the high amount of organic matter contributes to the increase in macropores, leading to a reduction in resistance to penetration and, as a result of that, to an increase in infiltration capacity. The density of individuals of the soil macrofauna in the upper 30 cm layer and soil presented the highest average value for Group 1, an intermediate value for group 2 and the lowest one for Group 3. We observed that the anthropogenic influences on vegetation and soil cause a direct and indirect reduction in the organic matter content, in density of individuals of the soil macrofauna and in biological porosity, contributing to a lower water infiltration rate.