Nutrient availability and organic matter content under different soil use and management

Abstract

The use of the system, handling and time adoption of these can effectively alter the quantity of organic matter (OM) and change the cycling of nutrients in the soil. This paper aimed at evaluating the availability of nutrients and OM contents in an Oxisol (Xanthic Ferralsol) located within a Cerrado area (Savannah ecosystem) of the Piauí State in Brazil, after years under different soil use and management systems. The treatments consisted of soils under no-tillage for three, six and nine years (NTS3, NTS6, and NTS9); pasture for two and six years (PA2 and PA6, respectively); eucalyptus plantation for six and 12 years (EU6 and EU12); conventional tillage system for two and eight years (CTS2 and CTS8) and native Cerrado (NC), which represented conditions of equilibrium. For each area, we assessed the levels of OM, pH in water, Al3+, H+ + Al3+, P, K+ , Ca2+ and Mg2+ at four soil depths (0.0-0.10, 0.10-0.20, 0.20-0.30 and 0.30-0.40 m) as well as the levels of Cu, Mn, Zn, Fe, B and S at 0.0-0.40 m depth, all with four replicates. Use and management systems provided significant effects on the availability of soil macronutrients and OM contents, but have inadequate levels of micronutrients in the soil, especially Boron. In areas under tillage, there is an increase in pH, availability of nutrients and OM in the surface layer, especially during the first six years of adoption of the system, while in the areas with nine years; there were an increase in P levels in subsurface. The areas under cultivation with eucalyptus show higher potential in increasing the OM levels in soil subsurface layers.