SOIL QUALITY INDICATORS UNDER DIFFERENT LAND USE SYSTEMS IN THE AGRESTE REGION OF PARAIBA, BRAZIL

Cropping systems modify soil attributes and may change its quality. The work had the objective to evaluate the changes in physical, chemical and biological soil under organic farming systems (soils cultivated organically for more than seven years), in conversion to organic and conventional, with reference to the soil under native forest, and identify the attributes used as indicators of soil quality. Three areas of farm crops, located in the municipalities of Areia, Remigio, and Lagoa Seca, the state of Paraiba, Brazil were selected, and soil samples deformed collected in the layers 0-10 and 10-20 cm. The data were analyzed using ANOVA, the Tukey Test, and the Principal Component Analysis. There was a reduction of soil density (Ds) and increased porosity (PT) in the system of organic farming compared to cropping systems in conversion organic and conventional. The contents of phosphorus and organic carbon (CO), the base sum (SB), cation exchange capacity (CTC), light particulate organic matter (MOPL), carbon particulate organic matter light (CMOPL), edaphic respiration (RE) and pH of soils under organic cultivation are higher than soils under conventional tillage. The growing organic basis contributes to the maintenance of soil quality under similar conditions and/or even better than the condition forest and, under the conditions of this study, the most appropriate indicators to analyze the cultivation organic basesare Ds, PT, CO, MOPL, CMOPL, pH, SB, CTC e RE.