Alterações dos atributos físicos e estoque de carbono do solo em diferentes sistemas de manejo no Cerrado

Abstract

The conversion of native Cerrado areas into agricultural systems has promoted changes in soil physical attributes and organic carbon dynamics, potentially affecting soil structure maintenance, water availability, and carbon storage capacity in cultivated environments. This study evaluated the effects of different sugarcane management systems on soil physical attributes and organic carbon stocks in Red Latosols in the Triângulo Mineiro region, Minas Gerais, Brazil. Six soil use and management systems were evaluated: Conv. 2 (conventional cultivation with two years of implementation), Conv. 3 (conventional cultivation with three years of implementation), Min. Till. 2 (minimum tillage with two years of implementation), Min. Till. 3 (minimum tillage with three years of implementation), Pasture, and Native Forest as an environmental reference. Soil samples were collected at depths of 0–10, 10–20, and 20 40 cm and analyzed for soil bulk density, macroporosity, microporosity, total porosity, mean weight diameter, geometric mean diameter, aggregate stability index, total organic carbon, and carbon stocks. The experiment was conducted in a completely randomized design in a factorial arrangement, considering six management systems, three soil depths, and five replications. Data were subjected to analysis of variance, and means were compared using Tukey’s test at a 5% significance level. The results demonstrated that management was the main factor responsible for changes in the evaluated attributes, whereas soil depth and the interaction between management and depth had a lower influence on most variables. The Min. Till. 3 system showed more favorable soil physical conditions, characterized by lower soil bulk density, higher macroporosity (24.17%), and higher total porosity (47.93%), presenting a similar behavior to Native Forest. The attributes related to aggregate stability showed greater structural preservation in Pasture and Native Forest systems, which presented higher values of geometric mean diameter, mean weight diameter, and aggregate stability index, highlighting the importance of permanent soil cover and continuous organic residue input. Management systems also influenced total organic carbon contents, with higher values observed in Min. Till. 2, Conv. 2, and Min. Till. 3 systems. Carbon stocks were affected by the evaluated management systems, with Min. Till. 3 presenting the highest carbon stock (43.40 Mg ha⁻¹), followed by Pasture and Native Forest. It is concluded that conservation management systems, especially minimum tillage after three years of implementation, have the potential to improve soil physical quality and increase carbon stocks in sugarcane cultivated areas in the Cerrado, contributing to agricultural sustainability strategies and natural resource conservation.