Two Field experiments were carried out in Wadi-Maged, west Matrouh city,
North Western Coastal Zone of Egypt (NWCZ), under natural rainfall conditions,
during winter seasons 2001-2002 and 2002-2003, to evaluate the rate of water soil
erosion under different percentages of gravel or natural vegetation cover. Soils of
Wadi-Maged are mainly sandy loam in texture with shallow profile. Soil cover by gravel or natural vegetation showed great potential for erosion
control on sloped area. The obtained results revealed that the depths of natural
rainfall through the two successive winter seasons were 123.1 and 118.3mm. The
lowest runoff value and amount of soil loss were observed for 25% natural vegetation
cover and 20% gravel mulch treatments. The average annual soil loss was
4.87ton.ha-¹ for bare soil treatment, while it reaches 2.41 ton.ha" for 25% vegetation
mulch treatment. The average annual soil losses were 2.81, 2.17 and 1.59ton.ha-¹ for
5, 10 and 20% gravel mulch of the soil surface, respectively. Leaving natural
vegetation and gravels at 25 and 10%, respectively, on the surface of cultivated
slopped soils in NWCZ areas led to decrease runoff and soil loss (wash erosion)
values by approximately 50%. Data indicate that the significant relationship between
average annual soil loss (y, ton.ha") or average annual runoff ~y, mm) and soil cover
by gravel (X, %) are fitted with the exponential equation: (Y=ab ). The results from this study demonstrate the extreme variability of erosion
measurements. This variability severely limits the usefulness of the data for
determining percentage of soil surface coverage needed to achieve a given level of
erosion control. Further studies are needed to define the relationship between soil
cover by natural vegetation and soil loss under the NWCZ conditions, Egypt.