الخلاصة:
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.
