The Study On The Law Of Soil And Water Losses And Treatment Facilities Of The Arbor-Shrub-Hedge-Gutter Method

Shanxi province is one of the most serious soil erosion in Loess Plateau region and is one of the key provinces of soil erosion in our country.The main way of soil erosion is water erosion,followed by the wind erosion. Aimed at the characteristics of physical geography,climate conditions,sand of storm and soil and water losses in the north of Shanxi province,and with the purpose of controlling the sand of storm and soil and water losses synthetically,a new method of controlling soil erosion -water conservation in arbor-shrub-hedge-gutter has been studied.The research of the method is still in initial stage.Combine the project supported by capital water resources sustainable utilization technical,this paper study on generation of runoff and sediment and related facilities under the conditions of arbor-shrub-hedge-gutter.Based on information collected the research was carded out by experimental research and the integration of numerical simulation techniques line.The main investigation contents are as follows:1.The experimental investigation of the effect of slope length on runoff and soil erosionIn this paper,the experiment are carried about the effect of slope length on runoff and soil erosion.The variety features of runoff and soil erosion are discussed and analyzed.The result shown that the runoff and soil erosion increases with the slope length increasing.2.The establishment and verification of mathematical model for runoff and sediment process on slop under the condition of arbor-shrub-hedge-gutter.Based on the characteristics of the runoff and sediment production on slope,generation and conflux of runoff under the condition of rainfall and producing sediment by rainfall and runoff this three process kinematic wave equation,a new model is set up coupled by soil moisture equation sediment transport equation.To calculate the model by using the finite method and to verify the model with measured data,the result indicates that the model can be used to simulate the rainfall-runoff and sediment process on slop under the condition of arbor-shrub-hedge-gutter.3.Research on design of section of water-storing ditchesDesign of section of water-storing ditches of different slope length according to 24h maximum rainfall once in a decade with observational data combined with model runoff on slope,the depth and bottom width of section of water-storing ditches of 30 meters,50 meters,80 meters are 0.774, 0.624meters;0.999,0.829 meters and 1.265,1.50 meters respectively.Lay out horizontal pipe with 30cm diameter to store runoff and prevent water and soil loss.4.Selection of afforestation speciesTaking the approach of factor analysis and comprehensive evaluation model comprehensively evaluate the vegetation site factors,according to the comprehensive index to implement the suitable tree species chosen.By using the gray interrelated analytical method to evaluate the main species suitability,The results shown that:The order of sand-binding and wind-controlling tree species is:the order of the arbor:Pinus sylvestris L.var.mongolica＞Pinus tabulaeformis＞Populus simonii;the order of the shrub:Hippophae rhamnoides＞Caragana microphylia＞Artemisia sp.＞Salix psammophila.5.The research on the structure configuration of artificial vegetation Proposing the reasonable vegetation structure based on the land resource,the water balance.The reasonable densities of shrubs are:Caragana microphylia 9913 strain/hm,Hippophae rhamnoides 1007 strain/hm:The reasonable densities of arbor is:Pinus sylvestris L.var.mongolica 4907 strain /hm.The space between main belts should be 15m,the direction of the broad-belt should be perpendicular to the main wind direction,and the direction of the narrow-belt also should be more than 45°angle to the main wind direction.