Previous studies showed the effectiveness of stone barrier contours on reducing slope lengths, retaining sediment and nutrients, and decreasing runoff, erosion rate and siltation of reservoirs. The extent of these benefits regarding to soil productivity in semiarid regions, however remained unknown. The aim of this study was to determine the effects of stone barrier contours on the productivity of a lithosol thirteen years after its construction. Experiments were carried out in areas of retained sediment and in areas where the topsoil layer was removed, in Quixadá, State of Ceará, Brazil, from March to July, 1994. Soil natural productivity was evaluated in both areas through yield and biomass production of cowpea (Vigna unguiculata) and corn (Zea mays). In areas of retained sediment, pod number per plant, grain weight per plant and yield of cowpea were respectively 48.6%, 140.0, 86.5 and 85.5% higher than those parameters estimated in areas of removed soil. Corn production was also affected beneficially by stone barrier contours since plant height, cob length and yield were 12.3, 20.7% and 16.5% higher in deposition sites than those in areas of removed soil.
erosion; soil conservation; stone barrier contour; soil productivity