Soil fertility characteristics were evaluated on a typical dystrophic Red Latosol (Typic Haplorthox) located in Passo Fundo, State of Rio Grande do Sul, Brazil, after eight years of use under mixed production systems (1993 to 2000). The effects of production systems integrating grain production 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 + red clover + birdsfoot trefoil)]; and system IV [perennial warm season pastures (bahiagrass + black oat + rye grass + white clover + red clover + birdsfoot trefoil)]; and system V (alfalfa as hay crop), which was established in an adjacent area in 1994. The areas under systems III, IV, and V returned to system I after the summer of 1996. The treatments were arranged in a randomized complete block design, with four replications. Exchangeable Al and Ca + Mg, organic matter, extractable P, and exchangeable K levels were influenced by crop production systems. The production systems increased the contents of organic matter, extractable P, and exchangeable K, mainly at 0-5 cm depth. Organic matter, exchangeable Al, extractable P, and exchangeable K levels decreased from the 0-5 cm layer to the 15-20 cm layer, while the opposite occurred with pH and exchangeable Ca + Mg contents.
crop rotation; ley farming; annual pasture; perennial pasture
