Soil physical attributes under different grazing management of winter forage crops in crop-livestock system at Southern Brazil

The effects of different species and grazing management of winter forage crops on the physical properties of a clayey Red Latosol of the western region of Parana State under crop-livestock integration systems were investigated in the present study. Treatments consisted of three different winter crops [white oat (Avena sativa), dual-purpose wheat (Triticum aestivum) and triticale (X Tritico secale)] and three grazing management (one and two grazing with 15 cm of residue height, and without grazing), followed by soybean cultivation, in a randomized block design. Undisturbed soil samples were collected at 0.00-0.10 and 0.10-0.20 m depths, after the winter crops harvest (October/2012) and soybean harvest (March/2013) and was determined the soil bulk density until 0.35 cm depth. The soil macroporosity in the 0.00-0.10 and 0.10-0.20 m soil layers and the total soil porosity in the 0.10-0.20 m layer, after winter crops harvest, were influenced by the crops and management of winter forage. In the evaluation performed after the soybean harvest, there were changes in the soil macroporosity in the 0.0-0.10 m layer and for microporosity and total soil porosity in the 0.10-0.20 m soil layer. The soil bulk density was not affected by the crops and management of winter forage. The different species and grazing management of winter crops in integrated crop-livestock systems promoted changes in soil penetration resistance in the 0.20-0.30 m soil layer. The cultivation of white oat during winter and management with two grazing resulted in lower soil penetration resistance levels.   Key words: Physical quality, soil structure, soil penetration resistance, conservation cropping systems.