The effects of irrigation and cropping on the properties of soils were studied in the region of the low-medium São Francisco river basin. Six sites were selected, three of them involving Oxisols collected at the Senador Nilo Coelho Project, in Casa Nova, BA, while the remaining three involved Ultisols collected at the Curaçá Irrigation Perimeter in Juazeiro, BA. The selected sites involved non irrigated and irrigated land, different crops and irrigation methods. The soils were morphologically characterized and samples were taken from each horizon to determine particle size distribution, -0.034 and -1.52 Mpa percent moisture, bulk density, particle density, total porosity, macroporosity, microposity, and saturated hydraulic conductivity. The results showed that the agricultural use of soil with irrigation promoted morphological changes resulting in the development of an Ap horizon showing abrupt transition to the underlying BA horizon and very hard consistency. The BA horizon was also affected in sites undergoing more intensive management. A significant increase in the surface textural gradient of the ultisols was observed to be directly related to the intensity of the management and water use. In the studied soils, the agricultural use with irrigation promoted an increase in the bulk density, and a decrease in macroporosity, total porosity and, consequently, in the hydraulic conductivity of the surface horizon.
Oxisols; Ultisols; physical properties; management practices; irrigation