Comparison And Analysis Of Soil Physical And Chemical Properties In Different Types Of Rhodiola Ex-situ Conservation In The Changbai Mountain

The research on ex-situ conservation of rare and endangered plants has become a hot issue now.Most of the studies focus on biological aspects,that is,from the protection of rare and endangered plants,to study how the ex-situ conservation has impact on plants,as well as summarizing experiences,so as to contribute to the conservation of biological diversity.However,there are few researches on that plants have impact on natural environment after ex-situ conservation.In this paper,I chose Rhodiola ex-situ conservation in the Changbai Mountain as my subject,to study how ex-situ conservation of plants had impact on soil which is one of the important natural elements.Based on large amounts of outdoor and indoor data,through comparative analysis of soil physical and chemical properties in different typesof Rhodiola ex-situ conservation,I hope it could contribute to the choice of Rhodiola ex-situ conservation in the furore,and at the same time,it could provide a theoretical basis to a better protection of rare and endangered plants and natural environment of the ex-situ conservation site.The main conclusion of this paper are as follows:(1) Different types of ex-situ conservation have different soil textures:it's sticky loam in sticky-leaved Korean pine forest,clay in Populus davidiana and Betula platyphylla,loam in base,and sandy loam in garden:The main factors are biological factors and human interference,in addition,Rhodiola ex-situ conservation changed the composition of the soil particles,and it made soil texture more porous. Soil bulk density values are lower than 1 g/cm~3 in different plots.Among them,the broad-leaved Korean pine forest,the Populus davidiana and Betula platyphylla have lower soil bulk density,but the base and the garden have higher ones.Rhodiola ex-situ conservation made the local soil bulk density smaller,but its changing rate was small.(2)The pH values are changing between 5.11 and 5.83 in different plots,soil there are all acid,Rhodiola ex-situ conservation made little influence on soil.(3) There're differences in soil organic matter content among different types of ex-situ conservation,in which the Populus davidiana and Betula platyphylla's is the highest,reaching 205.85g/kg,while the base and the gradenare a little lower. Rhodiola ex-situ conservation is better for accumulation of soil organic matter,but it played different roles in different types of ex-situ conservation.That there're differences between the two forests is related to the different forest types and the number of litter composition,nutrient uptake of different tree species,different quantities and types of micro-organisms under different conditions,and there're little relation to Rhodiola.The differences between the base and the garden are mainly related to the Rhodiola,the ones that ex-situ longer have more effects to soil organic matter accumulation. (4) Soil total nitrogen,total phosphorus,available nitrogen and available phosphorus content are changing between 4.68～11.56g/kg,1.86～4.78g/k,50.2～328.71 mg/kg,2.19～36.17mg/kg in different types of ex-situ conservation.Rhodiola had effect on the accumulation of soil nitrogen,but because the growing process of Rhodiola consumed large quantities of phosphorus,soil phosphorus content got significant reduction.(5) Soil bulk density,organic matter,total nitrogen,total phosphorus and available phosphorus content have high correlation to soil nutrient content,and played an important role in the principal component analysis,it could be used as the main indicator of soil fertility evaluation.To sum up,Rhodiola ex-situ conservation have greater impact on soil chemical properties than the physical ones.Among them,the effects on soil phosphorus is the most significant,on organic matter and nitrogen is a little,and on the texture,bulk density and pH value is little.