Soil fertility characteristics were evaluated on a typical dystrophic Red Latosol located in Passo Fundo, Rio Grande do Sul, Brazil, after five years of combined production systems (1993 to 1997). The effects of integrated grain production systems and with winter annual and perennial pastures under no-tillage were assessed. Four production systems were evaluated: system I (wheat/soybean, white oat/soybean, and common vetch/corn); system II (wheat/soybean, white oat/soybean, and grazed black oat + grazed common vetch/corn); system III [perennial cool season pastures (fescue + white clover + birdsfoot trefoil)]; and system IV [perennial warm season pastures (bahiagrass + black oat + rye grass + red clover + birdsfoot trefoil)]; and system V (alfalfa for forage), which was established in an adjacent area in 1994. The treatments were arranged in a randomized complete block design, with four replications under no-tillage. The production systems increased the contents of organic matter, extractable P, and exchangeable K, mainly at 0-5 cm depth. There was an increase in the pH value and exchangeable Ca + Mg contents in the first four production systems from the soil surface (0-5 cm) to deeper layers (15-20 cm). The reverse occurred with values of exchangeable Al. The systems with grazed perennial pastures showed higher organic matter content at soil surface, as compared to systems with annual pastures.
crop rotation; crop - pasture integration; annual and perennial pasture