Study On Soil Nutrient And Microbial Characteristics Of American Ginseng Root Zone Under Different Land Use Patterns

American ginseng is planted in three modes: under-forest conservation,forest cultivation and non-forest cultivation.Due to the implementation of forest protection and green water Qingshan project,it is strictly prohibited to grow American ginseng by cutting forest(forest cultivation),and it is inevitable to cultivate American ginseng in non-forest land.In this paper,the soils of three kinds of American ginseng under-forest conservation,forest cultivation and non-forest cultivation were studied.The soil nutrient,soil enzyme activity,soil microbial flora characteristics and interaction of the roots of American ginseng under three different land use patterns were discussed.Taking soil index of Under-forest conservation American ginseng as control standard,it provides a theoretical basis for soil improvement of non-forest cultivation American ginseng.Experimental results show that:(1)The content of nutrients in the rhizosphere soil of American ginseng is root zone layer> bottom layer of roots;the content of N,K,Zn,K,Cu,available and Ca,Mg,and Mn in the rhizosphere soil of under-forest conservation American ginseng,Both increased with the growth period of American ginseng;the non-forest cultivation American ginseng rhizosphere soil quick-acting and total N,P,and K contents were Huangyu area> Zuojia area> Ji'an area,Ca,Mg,Mn,Fe,Cu,Zn quick-acting and full-effect content are higher in Ji'an area;Forest cultivation American ginseng soil quick-acting Ca,Fe,Cu,Zn and full-effect N,Ca,5-year-old American ginseng root area soil content is higher,other elements distribution rules are not significant;The contents of quick-acting elements and total-effect elements are significantly and positively correlated.(2)Soil invertase,urease,acid phosphatase,catalase active root zone layer> root bottom layer under different land use methods;under-forest conservation American ginseng soil invertase,acid phosphatase urease,catalase,laccase The activity of ginseng increased with the extension of the growth period of American ginseng,while the activity of urease and cellulase decreased with the extension of the growth period of American ginseng.The soil microbial AWCD value of under-forest conservation American ginseng> Forest cultivation American ginseng> Non-forest cultivation American ginseng area showed that the soil microbial activity of Under-forest conservation American ginseng was the highest in the rhizosphere;Abundant,more diverse microorganisms,and strong ability to use different carbon sources.(3)The content of total saponins,Re and Rb1 in American ginseng is significantly positively correlated with the growth period of American ginseng.The total saponin content is very significantly positively correlated with the contents of available Zn and total Mn,and the contents of available Mn,Fe,Cu,and total P,Ca There is a positive correlation between monomer saponins and most soil nutrients;the total saponins and monomer saponins of American ginseng are significantly correlated with soil urease,acid phosphatase,catalase activities,and soil invertase,laccase,fiber The enzyme activity is significantly negatively correlated.(4)Alpha diversity and bacterial colony abundance of soil in the root zone of American ginseng are all under-forest conservation American ginseng> Forest cultivation American ginseng> Non-forest cultivation American ginseng.The composition of soil bacterial phylum and genus horizontal colonies in the root zone of Under-forest conservation American ginseng is similar to that in the root zone of Forest cultivation American ginseng.The species of bacterial colony markers in the soil of the root zone of Under-forest conservation American ginseng mainly include Acidobacteria,Proteobacteria,Rhizobia,Flavobacteriaceae,Chthoniobacterales and so on.(5)Alpha diversity of soil fungi in the root zone of American ginseng,non-forest cultivation American ginseng> forest cultivation American ginseng> under-forest conservation American ginseng;soil abundance,non-forest cultivation American ginseng> under-forest conservation American ginseng> forest cultivation American ginseng;soil fungus Beta Diversity is under-forest conservation American ginseng> Non-forest conservation American ginseng> Forest cultivation American ginseng.The composition of the mycophyta and genus levels in the root zone of Forest cultivation American ginseng and the root zone of non-forest cultivating American ginseng had a high similarity,and it was significantly different from that of the mycophylla and genus level in the root zone.The main species of fungal colony in the root zone soil of Under-forest conservation American ginseng are Amycolatopsis,Chrysospora,Chrysaceae,Russulaceae,Russula,Inocybe sindonia and so on.This article systematically analyzes the soil micro-ecological environment in the root zone of American ginseng under different land use methods,and clarifies the characteristics of soil microbial flora,soil nutrients,soil enzyme activities and their occurrence in different roots of American ginseng in different cultivation methods.It is the currently promoted non-forest land(Farmland)Cultivate American ginseng,provide data support for land selection and soil improvement.