Atributos físicos e biológicos do solo sob diferentes condições de uso nas várzeas de Sousa (PB)

Abstract

Changes in the soil are capable of modifying the natural functioning of the soil. This makes it a constant necessity to monitor the impacts of different types of use. Thus, the objective of this study was to evaluate biological and physical attributes of the soil under different usage conditions in Várzeas de Sousa, in the state of Paraíba. Sample collections were taken from Chromic Vertisol under different conditions of use (Tifton grass cultivation, pomegranate cultivation, and native vegetation) and sample depths (0-10 and 10-20 cm). The biological attributes that were analyzed were microbial diversity (colony forming units), microbial activity (basal respiration) and edaphic macrofauna (Tropical Soil Biology and Fertility). Physical characterization was performed for the attributes of textural analysis; soil density, macro and micro porosity, and total porosity, and water retention in the soil, specifically, field capacity, wilting point, and available water. According to the results obtained, it can be seen that the biological part of the overall microbial diversity was larger in the area under native vegetation, with highlights on the fungal genus Mucor, Gram negative bacteria, bacilli and cocci, regardless of the condition of use and depth. Microbial activity was greater in the area under Tifton hay and at superficial depth, regardless of the different uses. This area was also the one with the highest density of individuals of macrofauna, with highlights on Hymenoptera. However, diversity indexes show less diversity and equitability in it, probably due to the dominance of this group. Regarding the physical attributes, the textural analysis showed the predominance of silt and clay, micropores and low water retention capacity, regardless of the use and sample depths. The average density was higher in the sub-superficial layer.