[Soil physical properties of different hedgerow systems in upper reaches of Yangtze River]

Based on the investigation of present hedgerows in the upper reaches of Yangtze River, this paper analyzed the soil physical properties at different positions of three kinds of hedgerows (arbor, shrub, and grass). Comparing with those between the hedgerows, the soil physical properties within the hedgerows improved significantly. The average values of soil porosity, moisture content, saturated conductivity, water stable aggregates content, anti-erodibility index, anti-scouribility index, and clay content within the arbor, grass, and shrub hedgerows increased by 18.8%, 30.1%, 12.9%, 139.3%, 108.3%, 95.9%, and 25.5%, and the soil bulk density and sand content averagely decreased by 17.3% and 9.6%, respectively. The soil properties within the three hedgerows differed significantly. The soil anti-scouribility index within arbor hedgerow was the highest; the soil porosity, moisture content, saturated conductivity, anti-scouribility index, water-stable aggregates content, and clay content within the shrub hedgerow were higher than those within the tree and grass hedgerows; while the soil bulk density within the shrub hedgerows was lower than that within the tree and grass hedgerows. Because of the differences in the affecting degree of hedgerow on the soil physical properties at different positions of the three hedgerow systems, the related parameters presented definite horizontal variation at steep lands within, before, and behind the hedgerows, and between the hedgerows. The coefficient of variation (CV) of soil moisture content, anti-erodibility index, saturated conductivity, and clay content of arbor hedgerows was bigger than that of shrub and grass hedgerows, while the CV of soil bulk density, porosity, water-stable aggregates content, and anti-scouribility index of shrub hedgerow was bigger than that of arbor and grass hedgerows.