Based On Meta-analysis To Study The Effect Of Vegetation Restoration On The Eco-stoichiometric Characteristics Of Soil In The Loess Plateau

Soil eco-stoichiometric characteristics are important indicators for measuring the stability of soil ecosystems.Vegetation restoration on the Loess Plateau affects changes in soil carbon,nitrogen,and phosphorus,and thus changes in soil eco-stoichiometric characteristics.In this study,by using Metaanalysis comprehensive research methods,I read a large number of related literature and research reports,and collected more than 260 articles published independently related to soil carbon,nitrogen,phosphorus nutrient content and eco-stoichiometric characteristics after vegetation restoration in the Loess Plateau.And according to the purpose of the study to obtain relevant data from the literature,establish a database.The database includes parameters such as soil organic carbon,total nitrogen,total phosphorus,C:N ratio,C:P ratio,N:P ratio,and experimental background data such as latitude and longitude,average annual precipitation,vegetation restoration years,and vegetation restoration types.The overall impact of vegetation restoration on C,N,P elements and eco-stoichiometric characteristics in the 0-20 cm soil layer is analyzed,as well as the effects of vegetation restoration types,vegetation restoration years,and average annual precipitation on eco-stoichiometric characteristics.The main conclusions are as follows:(1)After vegetation restoration,the C and N contents of the soil surface increased significantly by 52.20% and 32.31%(P<0.05),but there is no significant change in the P content(P>0.05);the C:N,N:P,C:P ratio of the soil surface increased significantly by 17.35%,25.86%,and 55.27%(P<0.05).Surface soil C:N increases,soil organic matter gradually accumulates;N:P increases,reducing the limiting effect of nitrogen on soil nutrients,and is beneficial to the growth of vegetation with strong phosphorus absorption capacity;C:P increases,soil microbial phosphorus fixation ability strengthens,and the potential of releasing phosphorus in mineralized soil organic matter decreases.(2)The type of vegetation restoration has a significant effect on the topsoil eco-stoichiometric characteristics C:N,N:P,C:P(P<0.05).After arbor restoration,the C:N,N:P,C:P ratio increase by 31.00%,32.31%,and 68.21%.After shrub restoration,C:N,N:P,C:P ratio increase by 18.53%,24.61%,and 58.41%.After herbal restoration,the C:N ratio and N:P ratio don't increase significantly,and the C:P ratio increases by 25.86%.The degree of influence of vegetation type on soil eco-stoichiometric characteristics: arbor > shrub > herb.Under the premise of adjusting measures to local conditions,artificial trees and shrubs can be used to restore vegetation in loess plateau.(3)The period of vegetation restoration has a significant effect on the topsoil eco-stoichiometric characteristics C:N,N:P(P<0.05),but not on C:N(P>0.05).Vegetation restoration 1-5yr,6-10 yr,11-20 yr,21-30 yr,>30yr,N:P ratio increases by 7.25%,6.18%,16.18%,33.64%,44.77% respectively,and C:P ratio increases by 20.92%,17.35%,43.33%,58.41%,78.60% respectively.With the increase of vegetation restoration years,the surface soil C and N content gradually increase,and the P content is stable,so that N:P and C:P increase.After vegetation restoration,the soil C and N contents respond to environmental changes in a consistent manner,and the surface soil C:N is relatively stable.(4)Average annual precipitation has a significant effect on the topsoil eco-stoichiometric characteristics C:N,N:P(P<0.05),but not on C:N(P>0.05).When the average annual precipitation is <450mm,450-550 mm,> 550 mm,N:P ratio decreases by 6.76%,increases by 23.37%,37.71%,and C:P ratio increases by 12.75%,28.40%,40.49% respectively.The increase of precipitation in the Loess Plateau is beneficial to the increase of C and N contents in the soil,and P content is stable,so that N:P and C:P increase.