Land use change in Matopiba: impact of soil textural class variation on carbon quantity and quality

Abstract

Brazil has witnessed an accelerated agricultural expansion process in recent decades, with emphasis on the MATOPIBA region. Disturbance of natural areas is known to have a direct impact on soil organic carbon (C) dynamics, an attribute that plays a fundamental role in a series of biogeochemical processes. However, little is known about the impact of land use change on areas that had not been explored before and which are characterized by unique climate and soil aspects, as in the case of MATOPIBA. The objective of this study is to evaluate the effect of land use change on C quantity and quality in soils with different particle size classes located in areas of agricultural expansion in the Cerrado of Maranhão. The study will be conducted in the region of Maranhão, under the use of native forest and annual crops, the latter in textural gradients. The soil will be sampled to a depth of 1 m to evaluate the accumulation of C, nitrogen, microbial biomass C, ² - glucosidase activity, physical fractionation of soil organic matter (SOM), humification index and aggregate stability. The data will be submitted to analysis of variance (ANOVA) and the averages obtained will be compared through the Scott-Knott multiple comparison test (p <0.05) and principal component analysis (PCA). The analytical results will be integrated to express Carbon Management Index (CMI) and Soil Management Assessment Framework (SMAF), useful indicators as subsidies for decision makers associated with the expansion of Brazil's largest agricultural frontier. (AU)