Effects Of Salix Paraqplesia Restoration On Soil Properties And Vegetation In Alpine Desertified Meadow

Taking Hongyuan county and Ruoergai county as the research area,this paper studied the soil properties and vegetation characteristics under different years of restoration.Through the investigation and statistical analysis of vegetation under different restoration years,the change rules of plant community were revealed.Through laboratory experiments,the effect of Salix paraqplesia community on the physical and chemical properties of desertified soil were analyzed.In order to obtain the dynamic changes of soil and vegetation during the restoration of Salix paraqplesia community in the high alpine sandy soil in northwestern Sichuan,it provided a reliable basis for the further restoration and treatment of degraded and desertified grassland in northwest Sichuan.This study will provide a reference for formulating reasonable,effective planning for strategies of sand control.The main conclusions are as follows:(1)The restoration of desertified grassland by Salix paraqplesia community has made significant changes in soil water content,soil bulk density and soil porosity.The soil water content of desertified grassland increased with the increasement of restoration years.Compared with the none restored sample plot,the average soil water content in plots 3,5,7,9 and 12 years increased by 4.45%,16.22%,25.20%,49.65% and 88.12%,respectively.The soil bulk density dropped with the increasement of the restoration time of the Salix paraqplesia community.The soil bulk density about 3,5,7,9,and 12 years in the 0-10 cm soil layer decreased 0.06%,1.12%,2.09%,3.40% and 5.05%,respectively,compared with the none restored sample plots.Soil porosity increased slowly with the increase of restoration time.The average growth rate of soil total porosity in 3,5,7,9,and 12 years was 0.18%,1.44%,2.75%,4.44% and 8.75%,respectively,compared with the none restoration sample plots.(2)Soil fertility has been effectively improved during the restoration of Salix paraqplesia community.The results indicated that the content of soil organic carbon,nitrogen,phosphorus and potassium increased significantly with the increasement of the repair time of Salix paraqplesia community.There was an evident positive association between total nitrogen,ammonium nitrogen,nitrate nitrogen and organic carbon(P<0.01,r=0.947**,0.812**,0.972**).There was also an evident positive association between total potassium,quick-acting potassium and organic carbon(P<0.01,r=0.819**,0.956**).At the same time,total phosphorus and available phosphorus had evident positive association with pH value(P<0.05,r=0.501*,0.469*).(3)With the growth time of Salix paraqplesia community,the crown size of Alpine willows increased,creating better conditions for other plant growth.The number of plant species increased from 2 species to 13 species,and species richness index and evenness index increased.The quality of desertified grassland has been improved,and it has begun to develop towards a benign direction.(4)The species diversity and soil nutrient content of the desertified grassland vegetation are all showing a trend of continuous improvement,indicating the effectiveness of the engineering measures using the Salix paraqplesia community to repair the desertified grassland.This is the initial stage of the restoration of desertified grassland.The ecosystem is still very fragile and needs monitoring and protection.