The impact of vegetative cover type on runoff and soil erosion under different land uses

Abstract

The effects of different vegetation types on runoff generation and soil erosion were investigated. The study was conducted at the Southern part of West Bank, about 10 Km north-west of Hebron city, during 2005, 2006 and 2007. Five treatments were implemented; forests planted with P. halepensis (F), natural vegetation dominated by S. spinosum (W.S), natural vegetation where S. spinosum was removed (W/o.S), cultivated land (C), and deforestation (Df). Three types of data were estimated in each plot: runoff after each rainfall event, sedimentation at the end of the rainy season, and chemical and physical soil properties. The obtained results indicate that there are significant and important differences in runoff generation and sediment production with respect to the different types of vegetative cover. Forest and natural vegetation dominated by S. spinosum treatments exhibited the lowest amounts of runoff, with averages of 2.02 and 1.08 mm, respectively, in comparison to other treatments. The removal of S. spinosum significantly increased the total amount of runoff and sedimentation compared to the forest and S. spinosum treatments. In addition, runoff significantly increased (4.03 mm) for the Df treatment compared to that of the forest site. The greatest amount of sedimentation was observed in cultivated land and with deforestation. The forest and S. spinosum treatments exhibited the highest percentages of organic matter of the five investigated treatments. The results indicate that forests and natural vegetation dominated by S. spinosum prevent or decrease the risk of runoff and soil erosion. In conclusion, the removal of S. spinosum and forest trees as a means to improve rangeland productivity increases runoff and sediment fluxes if not accompanied by careful grazing management. In addition, interchangeably using arid and semi-arid lands as rangeland and for cultivation may have significant negative impacts on the production potential of these lands.