Effects Of The Different Restoration Measurements On Soil Property Improvement And Soil Erosion Reduction On Cutslope

Traffic inconvenience has been a bottleneck which restricted the economic development in mountainous areas. In recent years, in order to develop the rural economy, great progress has been made in the construction of the road network. However, owing to the long-term and short-term effects of the road on the ecological environment of the mountainous areas, road construction becomes increasingly controversial. An important manifestation of mountain road construction impacting on the environment expression is that the bare surface formed by the excavation will be serious soil erosion under rainfall.Cut slope is a production of high digging and deep filling in the mountain road construction. The characteristics of high steep slope, slope, low vegetation coverage, soil conditions, as well as the frequent anthropogenic disturbance make the natural recovery of the vegetation in cut slope extremely difficult. Taking the mountainous soil cutting slope as the research object, By setting up different models, including the ladder bucket+grass, grass and shrub, herbs, vegetations and natural restoration etc, combine with the long-term observation, studying the improvement of the different vegetation restoration models impacting on the soil properties and nutrient status of cut slope, and to explore its mechanism of prevention and control on slope erosion, we can draw the conclusion as follows:(1) Natural restoration of vegetations on the cut slope is so long a process that the speed is very slow without human’s intervention. The requirements of soil and water conservation can be achieved through the artificial cultivation of herbs and shrubs, which is the way to cover the surface quickly. Most of all, the restoration speed of vegetations is fastest in two ways, that is to say the ladder bucket+grass and grass and shrub.(2) In terms of improving the efficiency of soil physicochemical properties, the methods of ladder bucket+grass and grass and shrub can do more well on the improvement of some indexes such as soil bulk density, saturated hydraulic conductivity and water stable aggregate, besides, it is remarkable of the way of combining the herbs of fibrous root and shrubs with taproot system to enhance the soil infiltration ability on the road slope. (3) The improvement of vegetations acting on soil nutrient properties can be easily found in the index of organic matter and total nitrogen, whereas there is little effect in improving soil phosphorus content within a short time.(4) The vegetation cover can control the.rainfall-runoff on slope greatly and increase the threshold of rainfall erosion. By comparison, the method of ladder bucket+grass does best in alleviating soil erosion on the slop, followed by grass and shrub. The ability of intercepting sediment is much stronger in the methods of herbs and vegetations when the rainfall (P)<20mm.(5) Road slope erosion is affected by time factor. The natural restoration areas are lack of vegetation cover, so that it’s inapparent of the relationship between erosion per unit rainfall and time. The negative correlation between erosion per unit rainfall and time can be found in the methods of ladder bucket+grass, grass and shrub, herbs. In addition, when we use the method of vegetations, the relationship declines in power functionTo conclude, it’s much better to use the method of ladder bucket+grass than other methods to improve soil properties and reduce the slope soil erosion, but its high cost make it difficult for large area promotion, so the application field is limited. The measure of grass and shrub has a great advantage in deep soil, because the organic collocation of deep and shallow root system can not only protect the soil from rainfall erosion, but also effectively stabilize soil which is used for increasing the stability in deep soil. When it comes to herbs, the first thing we should consider is the survival rate, especially the grass seeding. Also in this measure, the early management and investment are higher, and the ability of intercepting sediment is lower than in grass and shrub on the cut slop.