The changes in some soil chemical properties, bulk density, and microbiological activity due to the replacement of a native forest by orange cultivation were evaluated in an Yellow-Red Podzolic Soil. The study was conducted at the Cambuhy orange farm, Matão (SP) in April, 1996. Two areas were selected: (a) a native forest, and (b) a 15-year-old orange plantation. Ten sites were randomly selected in each area and soil samples were taken at 0-20 and 20-40 cm depths. In the cultivated area, sampling was carried out in two positions: row (1 m from the tree), and interrow (4 m from the tree). The samples were analyzed for pH, base saturation percentage, phosphorus, cation exchange capacity, organic matter, bulk density, and microbiological activity. Statistical analysis was conducted using the t test. Orange cultivation had an effect on all the variables, mainly at the 0-20 cm depth. Cultivation decreased pH, base saturation percentage, organic matter, and cation exchange capacity. Conversely, there was an increase in the phosphorus content in the row and in the bulk density at both positions. The t value indicated that bulk density was the soil property most affected by orange cultivation, followed by cation exchange capacity, and organic matter.
soil management; natal orange; soil quality; soil degradation; sampling position; soil physical properties