FRAÇÕES E QUALIDADE DA MATÉRIA ORGÂNICA EM LATOSSOLO SOB DIFERENTES COBERTURAS NA CAATINGA

Abstract

Native vegetation plays a variety of ecosystem services, and are important for maintaining global climate balance and sequestering carbon from the atmosphere, thus, changing land use from anthropogenic action has the significant effect of changing the dynamics of matter The aim of this work was to determine, from organic matter quality indicators, the less degraded soil management and use system in Caatinga soils, between the agricultural system and pasture, through the physical fractionation of organic matter of soil and stratified ratio in Latosol. The research was developed in the municipality of Santa Luz (PI). The experimental design was a randomized block, consisting of three soils under the Caatinga domain: an area with native forest, pasture and agriculture. Samples of undisturbed and deformed soils were collected at depths (0-10,10-20, 20-30, 30-40, 40-60, 60-80 and 80-100 cm) with three replicates for each area. Physical fractionation of the MOS: particulate organic matter (PMO), C - associated with particulate organic matter (C - POM), C - associated with minerals (CAM), carbon management index (CMI) and stratified ratio. The vertical distribution of carbon affects the amount of PMO, C-PMO, CAM and CMI of the studied soil use systems. The pasture and agriculture coverages decreased the values of PMO, C-POM and CAM in the soil profile, none of these coverages had the capacity to restore the initial values of the soil, making it difficult to protect these fractions in the soil. Soil coverages with pasture and agriculture have a carbon management index of less than 100, which indicates a negative impact of soil management on the physical quality of these areas. The stratification ratio of organic carbon showed potential to be sensitive in identifying differences in management systems as a parameter of soil quality.