| Granite area in south China is the main soil erosion areas, which occupy28.58%of the area of granite erosion area. Because of climate, soil characteristics and human and other factors, red granite surface vegetation were serious damage and soil erosion is serious. Through the water and soil conservation engineering measures we can prevent soil erosion, and improve the soil physical and chemical conditions, then to promote vegetation recover quickly, but different engineering measures have different effects to improve soil conditions and vegetation restoration. Therefore, the study set three measures on granite, as slope were reverse-slope, platform and bamboo ditch. We research three soil conservation measures in the same site conditions of slope surface soil conditions and the influence of the vegetation restoration. The main research results are as follows:(1)the study researches vegetation growth after the same time in the arrangement of different measures. It show that the measures of Fish-scale Pits slope has the biggest influence to vegetation. The average growth in the face of Fish-scale Pits is the largest after five months, and the Anti-slope terrace measures growth is the second smallest, and bamboo groove within minimum growth measures. Growth of iquidambar formosana on the slope of Fish-scale Pits plot is also most in one year.(2)Survey analysis of the plant community alpha diversity change of within and without show that:three measures of measures inside and outside vegetation recovery naturally are different role, which Fish-scale Pits community best in vegetation restoration. The measures in vegetation diversity index measures:the measures in the measures Shannon-Weiner diversity index order:within the slope Fish-scale Pits> bamboo groove> Anti-slope terrace; Simpson dominance index performance: bamboo ditch> the slope platform inner> Fish-scale Pits inside; Pielou evenness index performance:within the slope Fish-scale Pits> bamboo groove> Anti-slope terrace. Measures for the vegetation diversity sort in outside:Fish-scale Pits> bamboo groove> Anti-slope terrace>control plot. (3)The influence of different measures on runoff sedimentThe three kinds of measures play a good role in reducing soil and water loss, they can also well control soil erosion.The order of reduce soil and water loss efficiency of the three kinds of measures is:Fish-scale Pits plot (24.60%)<Anti-slope terrace plot (34.24%)<bamboo groove plot (35.25%).(4) Soil erosion of different plot and Sediment deposition in different measuresTotal excavated volume of fish-scale pits plot, anti-slope terrace plot and bamboo groove plot was7.5m3, after a year, the Sediment deposition in three measures in sequence of fish-scale pits> bamboo groove> anti-slope terrace, and the soil erosion of all test plots in sequence of fish-scale pits plot> anti-slope terrace plot> bamboo groove plot> reference plot.(5) The distribution of soil moisture content under different treatments at slope scaleThe heterogeneity of soil moisture content at slope scale is upon the table. If we want to rationally allocate the vegetation on the granite red soil slope, we need to understand the variability of its soil moisture content. We studied the CV (coefficient of variability) of soil moisture content at different plots and directions, the results list below:values of CV in contour direction:control plot> anti-slope terrace> bamboo groove> fish scale pit; values of CV in slope direction:fish scale pit> bamboo groove> anti-slope terrace> control plot; values of CV in vertical direction:control plot> bamboo groove>fish scale pit>anti-slope terrace; values of CV in two-dimensional horizontal:fish scale pit> bamboo groove> control plot> anti-slope terrace; values of CV in three-dimensional:fish scale pit> control plot> bamboo groove> anti-slope terrace.(6) Soil physical and chemical properties under different measuresAll three kinds of measures can reduce soil bulk density, improve soil porosity condition, and benefit to the increasing of soil water retention. The bulk density in surface of all test plots in sequence of reference plot> bamboo groove plot> anti-slope terrace plot> fish-scale pits plot, while the sequence of capillary pore is opposite.We can draw the conclusion through the analysis of nutrient that fish-scale pits plot has a good function of fertilizer retention; the level trench and level bench have a significant improvement in available nutrient of different soil position, with an ascension range above30%. |
