Knowledge on chemical and physical soil properties provides the theoretical basis for a sustainable planning of natural resources. This study evaluated the alteration of chemical and physical soil characteristics in a Haplustox in the Zona da Mata region of the State of Minas Gerais (Brazil), under different crop systems. The systems evaluated were orange orchards, sugar-cane plantation, pasture and forest, as control. Orange orchards and pasture had been established more than 20 years before, both in succession to sugar-cane, previously grown for over a century. The sugar cane is a reminiscent of crop cultivated for more than 120 years. Soil was sampled in pits at depths of 0.0-0.2 and 0.2-0.4 m. The following chemical properties were evaluated: soil organic matter (MOS); pH in H2O, P, Ca2+, Mg2+, K, Al3+, H + Al, SB, CTC (t), and V, and the physical properties: texture, soil density, particle density, porosity, water retention curve, soil penetration resistance, and aggregate stability, as well as the ratio field capacity/soil total porosity. In the data evaluation, the crop systems represented treatments in a completely random design, and analysis of variance was performed for each depth separately. In the crop systems orange and sugar cane the chemical properties were improved, raising the nutrient levels and reducing the exchangeable Al3+, level but SOM was reduced and intermediate levels of physical degradation were observed. In the pasture system, low fertility and a dystrophic character were Stated, reduced SOM and high physical degradation, indicated by increased soil density and soil penetration resistance, and by lower porosity and aggregate stability.
Oxisol; soil use and management; soil degradation
