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vegetation cover defines the percentage of soil which is covered by green vegetation. leaf area index (lai) is an alternative measure of plant cover which gives the area of leaves in square meters corresponding to an area of one square meter of land. in a wide range of environments, vegetation cover greatly affects both surface water runoff and sediment loss (elwell and stocking, 1976; lee and skogerboe 1985, francis and thornes 1990). a vegetation cover of 45-50% is considered a critical value since above this value soils are adequately protected from raindrop impact and soil erosion is significantly reduced. vegetation cover can be measured in the field by assessing the percentage of the ground that it is covered by the existing annual or perennial vegetation. aerial photographs or satellite images can also be used for measuring vegetation cover of extensive areas.
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