Spatial variability of the physical properties and organic carbon in a Epiaquic Melanic under three management systems

Abstract

Understanding the spatial distribution of soil attributes is very important for setting the proper management of this resource. This study aimed to evaluate the variability of the physical properties and organic carbon in a Gleysoil Alitic Melanic typical clayey under three management systems in the municipality of Arari, located in the northwest of the state of Maranhão. Three areas of one hectare were selected in regular format of 100x100 m, with soil used for rice and livestock (area A), extensive cattle ranching on native vegetation (area B) and irrigated rice (area C), where soil samples were collected deformed in the 0-0.20 m depth, with a regular spacing of 10 x 10 m, totaling 121 samples per area and a total of 363. The variables analyzed were penetration resistance, bulk density, porosity (total, macro and microporosity), sand, silt, clay and organic carbon. Data analyzes were performed using descriptive statistics, average test and geostatistics. The values were higher for the variable resistance to penetration in the three areas, with an area A that had the highest average value (5.73 MPa), indicating the influence of crop-livestock combination in increased soil compaction. The variables exhibit spatial dependence in all areas, with the exception of sand and organic carbon in area A, whose variability may have been changed by management. Total porosity have greater spatial dependence and less variability, with different values for the three areas, despite the textural similarity, indicating that there were changes in their values with the management.