Estoque de carbono e qualidade do solo em cambissolo do semiárido baiano

Abstract

The soil adequate use and management are fundamentals for maintenance of fragile ecosystems sustainability, as savanna in the semi-arid region of Bahia state . An early stage identification of soil degradation and the land use according to support capacity associated with management practices that no affect the ecosystem are key-factors for achieving soil sustainability. The study was developed close of Lapão city, localized in northeast region of the Brazil. This study quantified cultivation effects on the soil use with castor bean and maize in a rainfed and irrigated system on the total stock of C, N find based on total organic carbon (TOC) and total nitrogen (TN); labile carbon, microbial biomass carbon (MBC), basal respiration and microbial activity in a Cambissoil. The Carbon Compartment Index (CCI) was calculated through of COT´s change in the agroecossystems and in savanna according to the equation: CCI = COT-agro ecosystem / COT-savanna. The Carbon Management Index (CMI), and the Soil Deterioration Index (SDI) were also evaluated. Soils agroecosystems had negative IDS comparated to reference system (savanna), showing degrading action of the intensive handling in the soil quality. The index of handling of carbon (IMC) increased on depth in all studied treatments. The rainfed maize presented the highest deterioration values on depths 0-0.10, 0.20-0.40, 0.40-0.60 m, being 47.13, 50.41, 49.01% respectively, while the system under center pivot presented lowest SDI.