| Scale effect is that certain value change with the scale of the space and time change. Soil physical properties and affected by the vegetation also have spatial scale effect, it is important to effects on hydrological adjusting function of vegetation. Therefore, to accurately evaluate and reasonable regulate the effect of forest vegetation hydrology, It is need to clear the spatial distribution and variation of soil physical properties Especially in an independent unit of the space-slope scale, Quantify the spatial scale effect, breaking the scaling bottlenecks.In the sub-humid small watershed of Xiangshuihe of the Liupan Mountains,We selected 2 representative slopes, one covered by the plantation of Larix principis-rupprechtii and another by natural shrubs,. In the Semi-arid small watershed of Diediegou of the Liupan Mountains, We selected 2 representative slopes, one covered by the plantation of Larix principis-rupprechtii and another by Natural grassland, Sample plots were set up continuously from the slope top downwards to slope foot. The soil physical properties were investigated in 2014 and 2015, through the ring core samples from different soil layers within the soil profiles of each plot. The results showed that:1) 10 years of vegetation restoration, soil physical properties has been some improvement. Comparative study soil physical properties covered by four vegetation types in the Semi-arid small watershed of Diediegou of the Liupan Mountains showed that:Compared with 10 years ago (2005), soil bulk density, total porosity and capillary porosity are reduced, Each soil layers vary between interannual are belonging weak variability, the variation in 0-100cm cross-sectional scale of change over time is significant; 0-80cm Each soil non-capillary porosity were significantly increased, An increase of Larix principis-rupprechtii (9.92%)> Hippophae rhamnoides Linn. (9.10%)> Ostryopsis davidiana Decaisne (7.06%)> grassland (2.37%), Corresponding increase in the amount of non-capillary water as Larix principis-rupprechtii (79.4mm)> Hippophae rhamnoides Linn. (75.21mm)> Ostryopsis davidiana Decaisne (56.48mm)> grassland (18.97mm); Different soil infiltration rate of the soil has increased significantly, an increase of larch (1.65mm/min)> Tiger hazelnut shrubs (0.85mm/min)> grassland (0.74mm/min)> Seabuckthorn shrub (0.28mm/min).2)The Soil physical properties increased linearly with increasing soil depths.but the amplitude is different. In four different slopes. With the increase of soil depth, soil density increases linearly, soil porosity, capillary porosity, non-capillary porosity, saturated hydraulic conductivity decreases linearly. Porosity corresponding holding capacity also gradually decreases with depth, the rate of physical properties change with depth in semi-arid area is better than change in sub-humid areas.3) Four slopes Soil physical properties showed a clear difference among slope positions, The whole-slope average of 4 slopes of soil physical properties are not appeared at the middle position of the slope. But in the entire portion of the slope or lower slope slope. The main cause of soil physical properties slope variation are difference:In the sub-humid the Larix principis-rupprechtii southeast slope is altitude, However, slope, vegetation growth also have affected. In the sub-humid the Natural shrub southwest slope is Vegetation growth status. In the semi-arid region of North China Larch Song Linxi North Slope is the slope, elevation and vegetation growth, but also have some impact; natural grassland in semi-arid area southeast slope elevation, slope, terrain and other factors.4) Analysis of soil physical properties scale effectand achieve a scale effect of slope scaling. Soil density, porosity, water holding capacity, saturated hydraulic conductivity rate exist obvious Slope effect, And different manifestations in different slope segments. The establishment of a different slope positions plots of soil physical properties and slope mean the difference between leaving the top of the hill with the level of change with increasing slope length relationship,... |
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