Experimental Study On The Effects Of Vegetation Removal On Soil Nutrients In Eroded Environment

The Loess Plateau is one of the most vulnerable areas in China's ecological environment.Soil erosion causes a large loss of soil nutrients,and vegetation restoration is an effective measure to improve soil erosion.After vegetation restoration,a large amount of plant biomass and litter are input into the soil,which improves the quality of the soil and plays an important role in the management and restoration of the local ecological environment.In this study,five typical small watersheds with different latitudes were selected in the Loess Plateau,and different terrains(erosion areas,sedimentary areas)were selected in each small watershed to set up test plots for a two-year vegetation removal test.We explored the relationship between topography,location and vegetation removal time,to establish the effect mechanism of vegetation on soil nutrients.The main conclusions obtained in this study were as follows:(1)There were differences in the changes of soil nutrients in different topography after vegetation removal.The effects of vegetation removal on soil p H,organic matter,nitrate nitrogen,available phosphorus and available potassium in the erosion area was larger than the sediment area;the ammonium nitrogen in the sediment area was larger than the erosion area;there was no significant difference in total phosphorus.(2)The response of soil nutrients after vegetation removal varied with vegetation removal time and topography.Soil p H,organic matter,ammonium nitrogen,nitrate nitrogen in the eroded area,total phosphorus,available phosphorus and other nutrients in the sediment area increased with the removal time of the vegetation;soil total phosphorus,available phosphorus,available potassium in the eroded area,deposition area the nutrient content of soil p H,organic matter,ammonium nitrogen,nitrate nitrogen and available potassium decreased with the time of vegetation removal.(3)The response of soil nutrients after vegetation removal varies with the time,place and topography of the removal.The p H value of the entire profile is in the deposition areas of Changwu,Guyuan and Ansai,the organic matter content in the deposition areas of Guyuan,Ansai,Changwu and Shenmu,and the ammonium nitrogen content in the deposition areas of Guyuan,the erosion area of Ansai and the deposition area of Suide.Erosion area of Shenmu,nitrate nitrogen content in deposition area of Guyuan,Ansai and Shenmu,total phosphorus content in deposition area of Changwu,Ansai,erosion area of Suide and Shenmu,available phosphorus content in deposition area of Guyuan,erosion area of Suide,erosion area of Shenmu,the content of available potassium in sediment area of Changwu,the erosion area of Guyuan,Ansai,Suide and sediment area of Shenmu are as follows: vegetation removal for 1 year > vegetation removal for 2 years;p H value is in erosion area of Suide,Shenmu,Changwu,organic matter content in erosion area of Suide,Shenmu,Changwu,ammonium nitrogen content in erosion area of Changwu,Guyuan,deposition area of Ansai,erosion area of Suide and deposition area of Shenmu,nitrate nitrogen content in erosion area of Changwu,Guyuan,Suide,total phosphorus content in erosion area of Guyuan,Ansai,deposition area of Suide,available phosphorus content in deposition area of Changwu,erosion area of Guyuan,Ansai deposition area,deposition area of Suide and deposition area of Shenmu.The content of available potassium in the eroded area of Changwu,the deposition area of Suide and erosion area of the Shenmu are vegetation removal for 2 years > vegetation removal for 1 year.(4)The dependence of soil nutrients of different terrains on vegetation removal is related to vegetation removal time.The dependence of the response of different soil nutrients to vegetation removal in the eroded area decreases with the extension of vegetation removal time;while the dependence of the response of different soil nutrients to vegetation removal in the sediment area increased with the extension of vegetation removal time.(5)The effects of vegetation factors and clay content on soil nutrient changes in eroded areas are higher than those in sedimentary areas.And it is related to the time of vegetation removal,and the impact on vegetation removal in one year is higher than that in two years.