Physical attributes and organic carbon of a Typic Hapludalf under soil management systems

The objective of this research was to evaluate the physical properties and organic carbon of a Typic Hapludalf in Pelotas, State of Rio Grande do Sul, Brazil, under different soil management systems on a farm. The assessed physical attributes were: soil bulk density, total porosity, macro and microporosity, particle size distribution, water dispersed clay, mean weight diameter of water-stable aggregates, and soil water infiltration, as well as organic carbon, in a factorial scheme in a completely randomized design with six replications. The management systems were studied for three years: no-tillage system with oats + vetch in winter and corn in summer; conventional tillage system with oat winter covering and corn in summer; conventional tillage (once plowing and once disking) with oats + vetch in winter and corn in summer; and native grassland. It was observed that soil under conventional tillage systems presented a higher total porosity and macroporosity in the 0.0-0.10 m, but higher microporosity in the 0.10-0.20 m layer; the no-tillage system presented the greatest values of soil bulk density in the 0.0-0.10 m layer. There was an increase in the soil organic carbon content for the no-tillage system, which was not reflected in an increase in the mean weight diameter of the water-stable aggregates.