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China Forestry Science Academe (2018)

Effect of Two Types Sand Barriers on Changing Sandy Environment and Vegetative Restoration

申景昕;

Titre : Effect of Two Types Sand Barriers on Changing Sandy Environment and Vegetative Restoration

Auteur : 申景昕;

Grade : Master’s Theses 2018

Université : China Forestry Science Academe

Résumé partiel
Mechanical sand barrier is one of the main technical means of desertification control in China.Salix Sand Barrier is a widely used type of sand barrier in the arid and semi-arid regions of Northwest China.Polylactic acid sand barrier(PLA)is a new type of sand barrier that does not pollute the environment.PLA sand barrier and Salix sand barrier are divided into two types(1 m×1 m、2 m×2 m).The study observes the diversity,amount,plant height,crown breadth of vegetation,analyses how the two sand barriers influences the spatial distribution and difference of vegetation.The study also research how sand barriers influence the ecosystem of sand dune by analyzing the chemical,physical,enzymatic and microbial characteristics of the sand dune.The main results are as follows :(1)In the study of restoration of natural vegetation in sand dunes,different types and sizes of sand barriers have different effects on vegetation restoration.PLA sand barrier and Salix Salix barrier increased vegetation density and vegetation coverage.The vegetation density of 1 m×1 m PLA sand barrier is 8.33 times that of bare sand dune.The vegetation density of 1 m×1 m and 2 m×2 m PLA sand barriers is 8.33 and 8.42 times that of bare sand dunes.The vegetation density of 1 m×1 m and 2 m×2 m Salix sand barrier is 3.67 times and 3.46 times that of bare sand dunes.The vegetation density of the PLA sand dunes in the middle of the sand dunes is larger.The vegetation density of the Salix sand dunes in the middle of the sand dunes is larger.The vegetation coverage of 1 m x 1 m and 2 m x 2 m PLA sand barrier is 13.32 times and 13.68 times than that of bare sand dunes.The vegetation coverage of 1 m×1 m and 2 m×2 m Salix sand barrier is 8.15 times and 8.38 times that of bare sand dunes.The vegetation coverage of PLA sand barrier in the middle part of the dune is larger,and the Salix sand barrier is largerr in the lower part of the dune.The plants diversity of PLA sand barrier is higher than Salix sand barrier.The plant diversity of 1 m x 1 m specification PLA sand barrier is better than 2 m×2 m PLA sand barrier.According to the above results,sand barrier is conducive to the restoration of dune vegetation,and PLA sand barrier is superior to Salix sand barrier.(2)In the study of vegetation distribution in the sand barrier,the vegetation is unevenly distributed in the sand barrier.In Grid of PLA Sand Barriers and Salix Sand barrier,vegetation density was the highest at corner and boundary of the grid.The vegetation within small-sized grid is concentrated.With size of grid increases,the vegetation is randomly distributed.The vegetation of the Salix Sand Barrier is evenly distributed.(3)The soil physical properties of the sand dune have been improved.The 1 m×1 m PLA sand barrier and the 2 m×2 m sand silage barrier significantly increased the soil water content in the 0-10 cm layer.The trend of soil water content distribution within the barrier was that the soil water content in the middle of the PLA sand barrier was higher than that in the marginal area of the sand barrier,and there was no significant difference in the Salix sand barrier barrier.With the increase of soil vertical depth,the daily change of soil temperature tends to be stable.The daily variation of soil temperature in 5 cm,10 cm and 20 cm soil layers was larger,and the trend was to increase first and then decrease ;30cm,50 cm layer soil temperature is stable.The distribution of soil temperature in sand barrier is changed with the change of solar radiation angle.Both the PLA sand barrier and the Salix sand barrier increase the hardness of the soil surface.The hardness of the soil in the PLA sand barrier is smaller on the upwind and downwind,and the middle of the sand barrier is larger.The hardness of the soil near the upwind in the 1 m×1 m Salix sand barrier is smaller.

Mots clés : PLA sand barrier; vegetation restoration; desertification; physical and chemical properties of the soil;

Présentation (CNKI)

Page publiée le 24 mai 2019