Qualidade do solo em áreas cultivadas e sob vegetação nativa no semiárido brasileiro

Abstract

Given the importance of the Caatinga biome, in recent years it has been exploited inappropriately, causing changes in its physical, chemical and biological structure. These alterations can be observed with the growing number of areas in the process of desertification, which brings with it erosion, compaction, alteration in the thermo-hydric behavior, reduction of biota and organic matter, that is, processes responsible for the availability of nutrients for plants. The present work aimed to understand the thermo-hydric and biological dynamics of the soil in two seasons of the year, as well as to verify its quality through the chemical and physical attributes, in different managements, namely: an area of native vegetation, one with the cultivation of the species Anadenanthera macrocarpa and another with the cultivation of Moringa oleifera, located at the São Gabriel Farm, in São José de Espinharas, Paraíba. To verify the quality of the soil, changes in physical and chemical attributes were analyzed, and these parameters were observed in the three study areas, at depths of 0-10 and 10-20 cm. The physical attributes studied were: soil density, particle density and total porosity. Among the chemical attributes of the soil, the following were studied: pH, P, K+, Na+, H+ + Al+3, Al+3, Ca+2, Mg+2, MO, sum of bases and CTC. For the survey of soil macrofauna, the “Provid” method was used, where ten traps were placed in the three areas, remaining in the soil for 96 h. After that time, they were taken to the laboratory to perform the counting and determination of the number of individuals and measurement of their biomass. Related to the soil thermo-hydric study, a digital thermometer was used to evaluate the temperature on the surface and in depth; to determine the water content, aluminum capsules were used, and these parameters were collected every three hours for a period of 24 hours in the study areas. After collection, the aluminum capsules were weighed to obtain the wet mass and then placed in an oven at 105º C for a period of 24 h to determine the dry mass weight. To calculate the terrestrial surface temperature of the images obtained from the thermal sensors of the Landsat-8 satellite, the Open Source software Qgis version 3.10 was used, which aimed to compare with the data obtained with the measurement carried out with a digital thermometer. Then it is concluded that there are physical and chemical differences in the types of management, and the area where water management was used had a greater number of edaphic individuals; and that obtaining orbital images is a satisfactory methodology for studies of thermal amplitudes on the Earth's surface.