CARBONO ORGÂNICO E ATRIBUTOS FÍSICOS DO SOLO SOB MANEJO AGROPECUÁRIO SUSTENTÁVEL NA AMAZÔNIA LEGAL

Abstract

Studies aimed at raising the quality of Amazonian soils have grown in the last decade because their inadequate use may limit the capacity of their production. In the Amazon Region, research shows that agriculture contributes to the increase of degraded areas correlated to deforestation, however, this practice has considerable importance in the economy. Thus, the objective of this work was to evaluate the levels of density, total porosity, macro and microporosity, organic carbon contents and to quantify the carbon stock in the soil profile layers in an ICLF system and in conventional systems in the municipality of Paragominas, Pará. A completely randomized design was used, with three replications, in a plot scheme subdivided with four plots (soil management systems) and seven subplots (soil layers). The plots were composed of: ICLF-Paricá system, conventional tillage maize (TM), pasture managed with cattle breeding in extensive system (PE) and as a secondary forest (FS). The subplots were the sampling depths: 0-10, 10-20, 20-30, 30-40, 40-60, 60-80 and 80-100 cm. The ICLF-Paricá integration system, at five years of cultivation, improved the physical conditions of soil density and porosity, as well as the levels and stocks of organic carbon in the subsurface layers. PM promoted increased soil density and loss of total porosity and microporosity in depth, but presented levels and stocks of organic carbon similar to the integrated croplivestock-forest (ICLF) system. The pasture showed levels and stocks of organic carbon similar to the secondary forest, but indicated a reduction of macroporosity. (English) [ABSTRACT FROM AUTHOR]