Atributos ed?ficos e fauna do solo em ?reas de integra??o lavoura-pecu?ria no Bioma Cerrado, Mato Grosso do Sul

• Autor(a) principal: Batista, Itaynara
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRRJ
• Texto Completo: https://tede.ufrrj.br/jspui/handle/jspui/2717
• topic: Mat?ria org?nica; Agrega??o do solo; Invertebrados; Organic matter; Soil aggregation; Invertebrates; Agronomia

The growing demand for food and the search for new productive areas, plus the concern about the impact of agricultural practices on environment stimulated development of production systems in which conservation is emphasised. The integrated crop-livestock (ICL) system shows great potential for improving pasture quality, since the crop rotation, particularly of cereals, deposit a large quantity of crop residues in the soil, thus protecting the agroecosystem and providing nutrients. This study was conducted in the integrated crop-livestock (ICL) areas of Cabeceira Farm, Maracaj?, State of Mato Grosso do Sul, Brazil. The areas evaluated were: Cerrad?o woodland, pasture/corn, corn/cotton and cotton/soybean rotation. Evaluations were carried out in the dry season (May 2009) and in the rainy season (March 2010), to analyse the impact of the integrated crop-livestock system on chemical, physical and biological soil properties. The evaluations comprised characterization of sorption complex, granulometry analysis, granulometry fractionation of soil organic matter (SOM), determination of oxidizable fractions of organic matter, and identification of edaphic macrofauna and aggregation formation pathways, where three types of aggregates were established: physiogenic, biogenic and intermediate. The relative composition (%) and the stability of different aggregate types were evaluated, and their sorption complex was characterized. The dynamics of the sorption complex and SOM were affected by seasonal variations. The carbon pools varied with both granulometry fraction and oxidizable fractions. The type of SOM compartmentalization can be used to evaluate quality of soil management. The most important compartments are the particulated organic carbon (POC) in the granulometry fraction, and the F1 and F2 fractions of oxidizable fractions. In general, the structure of edaphic macrofauna community was influenced by the crop present at the time of the evaluations, and the crop residues from previous cultivation, due to different levels of nutrients available upon their decomposition. The highest values for density of individuals, mean richness, and total richness were found in Cerrad?o woodland area, for both evaluation periods. However, the diversity and richness indices observed in this area were not the highest, because some groups dominated, principally Isoptera. The areas with the highest values of evenness were the corn/cotton rotation area, in the dry season, and the cotton/soybean one in the rainy season. The Pielou index values were of 0.75 and 0.80, respectively, both showing high levels of total richness (17 and 14), and low group dominance. When comparing only the aggregate formation pathways and evaluation seasons, the quantities of biogenic aggregates were generally lower than the quantities of physiogenic, and intermediate aggregates. The greatest content of total organic carbon was found in the biogenic aggregates, in the dry season, and in the intermediate aggregates, in the rainy season. This pattern suggests that the biogenic aggregates of the dry season originated the intermediate aggregates in the rainy season.