Soil physical properties and soybean yield after one year of a cropping livestock integration system in an area under notillage / Atributos físicos do solo e produtividade da soja após um ano de integração lavoura-pecuária em área sob plantio direto

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The inadequate use of tillage systems and grazing pressure above the capacity of support of the soil and the pasture are related to the degradation of the soil, especially by compaction. The negative effects of the animal on the soil are one of the main problems in managing cropping-livestock integrated systems. With the objective of evaluating the effects of beef cattle grazing during the winter on soil physical properties and soybean yields, a study was carried out in Castro, PR, in southern Brazil. The soil is a clayey Reddish-yellow Latosol, light wavy relief, with a Cfb climate type. The experiment had four grazing levels on the wheat (Triticum aestivum), followed by soybean crop (Glycine max), with three replicates in a random block experimental design. The treatments were: without grazing; 15, 30 and 45 days of grazing. The introduction of the animals in the area happened 50 days after the wheat emergence. Steers used have a mean live mass of 260 kg, with a stocking rate of 4.0 AU (animal unit = 450 kg LM) per ha. The soil samples were collected at the end of the wheat cycle, in the layers of 0 to 5; 5 to 10 and 10 to 20 cm depth. The performed analyses were pore size distribution, wet stability of the aggregates, flocculation degree, bulk density and resistance to penetration of the soil. The grazing intensity negatively affected soil macroporosity, total porosity, wet aggregate stability, flocculation degree, bulk density and penetration resistance, mainly under the more intense grazing treatments, 30 and 45 days, showing soil physical modifications due to animal trampling. These soil changes were more pronounced in the 5 to 10 cm depth, indicating effects of the previous use under no-tillage systems. Soil bulk density levels were considered low to this textural class, but macroporosity and resistance of the soil to the penetration were near to critical levels, showing compaction. Soybean grain yields were similar among the grazing intensity treatments at the end of first year study, possibly related to satisfactory soil physical conditions adequate to plant root development.

ASSUNTO(S)

pastures plantio direto soil physics soja fisica do solo física do solo pastagens soybean

ACESSO AO ARTIGO

Documentos Relacionados