Carbon stock and emission of CO2 in managed and native areas in the south Cone Region of Mato Grosso do Sul

Abstract

Great demand in food, fibers and energy triggers the modifications of native areas in production system which, throughout time, jeopardize soil and carbon stock. Current analysis evaluates the dynamics of total organic carbon (COT) of the soil at different management systems in the municipality of Mundo Novo MS Brazil. Two managed areas were evaluated: permanent pasture with coast-cross (Cynodon dactylon), (pasture - PA) and an area with the same conditions as the PA area which, in March 2016, was isolated and planted with native trees (recovery area - AR) and a reference are (native wood -MN). Three soil collections were undertaken, at layers 0-0.05, 0.05-0.1 and 0.1-0.2 m, or rather, at implantation of recovery, after six months and after twelve months. Soil density (Ds), total organic carbon (COT), stratification indexes (IE), carbon stock (EstC), variation in EstC (ΔEstC) and mineralizable carbon (C-CO2) were calculated. PA area had the highest Ds rate, with 1.72 Mg m-3. AR had the highest rates of COT, with increase (17.31, 18.70 and 22.67 g kg-1) at 0, 6 and 12 months respectively and a subsequent increase in IE, and greatest EstC rates after 12 months. AR and PA areas show positive rates of ΔEstC with regard to MN area. There was a greater biological activity represented by C-CO2 emission in AR up to six months after the isolation of the area, with a decrease after 12 months. Isolation and reforestation contribute towards an improvement in edaphic environment due to time when compared to the soil´s organic fraction.