Frações oxidáveis do carbono orgânico total e macrofauna edáfica em sistema de integração lavoura-pecuária

• Autor(a) principal: Batista, Itaynara [UNESP]
• Data de Publicação: 2014
• Outros Autores: Correia, Maria Elizabeth Fernandes, Pereira, Marcos Gervasio, Bieluczyk, Wanderlei, Schiavo, Jolimar Antonio, Rouws, Janaína Ribeiro Costa
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1590/S0100-06832014000300011; http://hdl.handle.net/11449/114124
• topic: matéria orgânica; sazonalidade; manejo; invertebrados; organic matter; seasonality; management; invertebrates

The increasing level of land degradation has led to the adoption of agricultural management practices that seek to combine agricultural production and soil conservation. Among these, the practice of Crop-Livestock Integration (CLI) has intensified in West-Central Brazil. In order to assess the long-term effect of the CLI system and seasonality on the community of soil macrofauna and oxidizable fractions of total organic C in croplands and the Cerradão (Brazilian tropical savanna), a study was developed at the Cabeceira Farm in the municipality of Maracaju, State of Mato Grosso do Sul, which measured the effect of CLI on oxidizable fractions of total organic C and soil macrofauna. The CLI system has been used in this area since 2003. The soil was identified as a Latossolo Vermelho (Ferrasol), on flat land. The areas sampled have the following history of use: soybean/corn + brachiaria grass/cotton/oat + pasture/soybean/implantation of pasture/pasture. Sampling was carried out in two seasons, dry and wet. In the dry season, the crops were pasture, corn+brachiaria grass and cotton; in the rainy season there were corn+brachiaria grass, cotton, and soybeans. Thus, the areas in the two evaluation periods were pasture/corn, corn+brachiaria/cotton, cotton/soybeans, and an area of native Cerrado. Sampling was performed at the depths of 0-10, 10-20, and 20-30 cm, and the following determinations were made: analysis of soil macrofauna, particle size fractionation of soil organic matter (SOM), and oxidizable fractions of total organic C. The areas do not have an experimental design as this is an observational study. Data were compared by the Kruskal Wallis test at 5 % probability and through analysis of redundancy. Compartmentalization of SOM can be used to assess the quality of management, with the most sensitive compartments being the F1 and F2 fractions in the assessment of oxidizable fractions. These fractions are more labile in the soil, whereas the F3 and F4 fractions are more recalcitrant. Isoptera (termites) may be acting as a wetting agent of organic matter in the Cerrado area, contributing to higher levels of F3 and F4, compared to F1 and F2, in the dry season. This pattern was only observed in the Cerrado area since in the production areas, Isoptera is controlled by management practices. The lack of these insects in the CLI system may be reducing the stabilization of SOM in the F3 and F4 fractions.