Biota do solo e a atividade microbiana de áreas em diferentes estágios sucessionais e aspectos sócio-econômicos no município de Santa Terezinha-PB.

Abstract

The Caatinga is currently undergoing in strong process of degradation, caused mainly by deforestation and inappropriate use of natural resources, in which there is irretrievable loss of plants and animals diversity, acceleration of erosion and declining soil fertility. This study aimed to evaluate the evolution of CO2 from the soil and to quantify the organic matter, organic carbon and light organic matter of the soil, knowing the diversity of macro-and mesofauna in Caatinga at different stages of natural regeneration during the period July 2007 to June 2008, located on the Tamanduá Farm, Santa Terezinha County, Paraíba. It was determined the evolution of CO2 from the soil, the quantification of organic carbon and organic matter and the light organic matter soil by flotation in water. The content of soil moisture and temperature are the factors that most influenced the microbial activity. Regardless of the level of cover vegetation of the caatinga, the CO2 production is similar across the four levels of regeneration studied, the highest levels of organic carbon and organic matter occurs in the Climax area, the area covered by pasture grass traps larger amount of organic matter of light fraction and, organic carbon and organic matter are the parameters that best reflect the decline of carbon in different stages of regeneration of the savanna, and can be used as indicators of soil quality. For the evaluation of edaphic macrofauna were used PROVID trap type and modified for the extraction of mesofauna we used the method of Berlese - modified Tullgren. The availability of water, vegetation and temperature are crucial in the distribution of animal groups. In the composition of macrofauna in different areas and periods studied, the main groups are Hymenoptera and Diptera in the dry season and Diptera and Hymenoptera in the rainy season. The dominant groups in mesofauna are Collembola and Acarina in the dry season and Acarina and Collembola in the rainy season. The abundance of macro and mesofauna little change as a function of successional stages evaluated. When evaluating the vulnerabilities and identify the key socioeconomic and environmental impacts in the city. The results indicate that the contents of the vulnerabilities social, economic, technological and dry, with values 28.1, 66.5, 69 and 70.2%, respectively, relate to the socioeconomic and environmental constraints and lack of public policies geared to the needs of the population. Farmers have no technical 13 assistance from government agencies, poverty is portrayed disturbing and retirement of the peasants for many families is the main or only source of income. Insufficient water infrastructure enhances the vulnerability to droughts and family farming dominates the city, based on subsistence agriculture.