Estabilidade de agregados, carbono orgânico e glomalina do solo em um sistema agroflorestal em estágio inicial

Abstract

The evaluation of the physical and chemical attributes is important to measure the soil quality. Thus, the aim of this study was to analyze dystroferric Red Latosol (Oxisol) samples in a two-years-area of agroforestry. The study was conducted at APAE Rural in Campo Mourão - PR. Ten points were delimited in the area called Agro 2, to verify the attributes of the soil at each point, collecting deformed and nondeformed samples of soil. The parameters evaluated through particle-size analysis, gravimetric moisture content, bulk density, organic carbon, organic matter, carbon stock, easily extractable glomalin, and stability of aggregates, which were related to each other. It was verified that the moisture and density contents presented similar behavior when compared to each other, and this second one showed the variation of the results in the points within the limits of the clayey soils, texture verified through particle-size analysis. The carbon and organic matter contents were predominant in the superficial layers of the area points. The carbon stock was directly influenced by the carbon content and bulk density. The soil of the area presented high levels of glomalin (5.38 mg/g at 27.53 mg/g), a glycoprotein which has influence on carbon content and soil aggregation. In addition, this soil presented stable characteristics in all points of the area, with samples of mean weight diameter (MWD) higher than 0,25mm.