Qualidade física, química e do estoque de carbono do solo em áreas sob diferentes sistemas de manejo no cerrado

Abstract

The management systems used significantly affect soil attributes in areas included in the production process of the Brazilian cerrado, which generally cause some type of deterioration in soil quality. This study aimed to quantify and qualify the physical, chemical attributes and soil carbon stock in areas under different uses. The experimental design was completely randomized, where four areas with different management were evaluated: Agroforestry system (SAF); Area cultivated with sugar cane (Cane); Brachiaria pasture (PA) and; Native semi-deciduous riparian forest (MN), with five replications. Deformed and undisturbed soil samples were collected during the rainy season at four depths, from 0.0-0.10; 0.10-0.20; 0.20-0.30 and 0.30-0.40 m, to evaluate chemical attributes, total organic carbon (TOC) and its stock in the soil (EstC) and the following physical attributes: Soil density (Ds) , macroporosity, microporosity, total porosity and mechanical resistance to root penetration (RP). The geometric mean diameter, weighted mean diameter, aggregate stability index (IEA), percentage of aggregates with a diameter greater than 2 mm (AGRI index) were calculated, and the sensitivity index (SI) was calculated for some attributes evaluated. . The Agroestat software was used to perform the analysis of variance and, when significant, apply the F test to the data. Soil uses and occupation alter the chemical and physical attributes and carbon stock in the soil significantly, regardless of the time of use of each of them. The MN area presented the highest values of the macronutrients and micronutrients evaluated, followed by the area in SAF, then by the area with sugarcane and pasture, which presented similar values to each other. For most physical attributes, low values were almost always found in the area cultivated with CA, where through Ds and RP it was found that the soil was compacted; The highest aggregation indices (IEA and AGRI index) were observed in the SAF area, followed by PA, MN and CA; The IS showed that all systems reduced the TOC content and EstC of the soil by more than 60% compared to native forest. The highest EstC values were found in MN in all soil layers, while in the CA, PA and SAF areas they have equal values up to 0.20 m depth.