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Inner Mongolia Agricultural University (2010)

Study on Slope Erosion Differentiation Law and Control Measures in Desert Grassland

蒙仲举; Meng Zhong Ju

Titre : Study on Slope Erosion Differentiation Law and Control Measures in Desert Grassland

Auteur : 蒙仲举; Meng Zhong Ju

Grade : Doctoral Dissertation 2010

Université : Inner Mongolia Agricultural University

Résumé
As the changing of global environment and the negative disturb by human being, the vulnerable desert grassland in north of China had different kinds of degradation and desertification. Based on this, the study conducted on Xilamuren desert grassland, and did the research on environmental variation character systematically by using the method combining field periodic observation with artificial simulation. The paper focus on wind erosion and water erosion on the slope, the related mechanical analyses was done. The research also covered the counter points restore of slope and discussed a little on water conservation and erosion control. The result showed as follow :(1) Coarse grained in the top slope, fine particle significantly reduced. The distribution of fractal dimension of soil particle and isohypse line showed some regulations, as the topography went from high to low, the fractal dimension increased. Fractal dimension of soil particle and sand grain content were negative related, but positive related with clay content. The soil texture had important effect on soil organic matter. The fine particle and organic matter reduced because of the different vegetation coverage in different position of slope. The organic matter had the negative relationship with coarse grain, but positive relationship with fine particle.(2) In the different spatial scale, soil moisture affected by many factors. For 0-30cm layer, the soil moisture had the better consistence in the low swale, while the soil moisture in the middle of slope showed uneven distribution, and the worse consistence. Soil water supply ability and water holding ability in low land and bottom of swale were better. The infiltration rate was top of slope >middle of slope>bottom of slope> low swale. Soil initial moisture content , total pore space and soil compaction were significantly related with soil infiltration rate. The procedure of soil water infiltration can be better reflected by Horton infiltration equation.(3) Big spatial differences were among the intensities of wind erosion, the wind erosion decreased from top of slope to the bottom. Vegetation coverage and wind erosion showed power function relationship. The effective vegetation coverage of resisting wind erosion in grassland was 60%. The surface soil moisture and wind velocity had negative relationship, sediment discharge improved as the wind velocity increased. The different interactions were found among vegetation coverage, wind velocity and soil moisture on sediment discharge. The interaction of wind velocity and vegetation coverage was the most effective one.(4) Highest silt content appeared in runoff yield prophase, it took 69.06% of all collected silt content, the most soil lost in runoff yield prophase. Gravel content was high in runoff prophase, the content of silt、clay obviously increased in the late part of runoff. The relationship of sediment content and antecedent soil moisture showed the parabolic trend. In desert grassland, the soil moisture is 17.5% in the early time of surface soil loss. Vegetation can help in reduce soil surface runoff, the river closure function of vegetation acted early stage of runoff yield.(5) After applying of water-retaining agent, the water holding capacity decreased in different level. The ability of releasing water improved and as more water-retaining agent was applied, the soil erosion was decreased. Cover of litter and rocks had the significant effect on reducing sand and water. Irrigation showed the significant improving effect on the growth of vegetation

Mots clés : Desert grassland; Wind erosion; Water erosion; Water conesrvation; Surface cover; Supplementary irrigation;

Présentation (CNKI)

Page publiée le 2 mai 2013, mise à jour le 3 mai 2018