Frações de matéria orgânica de um argissolo enriquecido com cálcio em função da qualidade da biomassa aplicada

Abstract

Intcnsivc agriculturc causes land degradation and contributes to global warming due to C02 conditions rclcased into thc atmosphcrc becouse of thc conversion of nativc to agricultural ccosystcms. In this context, soil organic mattcr (MOS) is esscntial for maintaining thc productivity of tropical soils. This study aims to determine thc variations in thc carbon fractions of an ARGISSOL cnrichcd with calciuni submittcd to a no-tillagc systcm and thc application of biomass of differcnt qualities. Thc cxperimcnt was conductcd in thc experimental arca of thc State University of Maranhão, São Luís campus. In this experiment, thc trees wcrc previously preparcd in 1996 and, in 2020, thc number of plots of thc cxperimcnt was reduced for two, which wcrc divided in rclation to the prcsencc or absence of Mombaça grass, thc design used for randomized blocks, with 4 blocks and 6 treatments, which arc: Sombrciro + Leuccna (S + L); Acacia + Leuccna (A + L); Leuccna + Glyricidia (L + G); Acacia + Glyricidia (A + G); Sombrciro + Gliricidia (S + G) and Control. The analyzcs carricd out wcre in rclation to thc fractions of organic matter in the soil, from the total organic carbon and its fractions, particulatc organic carbon and associated with the mineral, as wcll as indicators such as soil microbial biomass and Chemical attributes for Ca + 2 and organic matter. The results of this study confirm our hypothesis that higher quality biomass favors an increase in the MOS fraction associated with the mineral. The variations of the organic matter fractions, the microbial quotient and the organic carbon associated with mineral / soil microbial biomass ratio causcd an increase in thc stable fraction of MOS. These results indicate that the use of high-quality biomass is an adequate strategy to increase soil carbon sequestration, which can dccisively contribute to reduce thc release of C02 into thc atmosphcrc, change land suitability and cmancipalc farmers from the humid tropies.