| At present,due to the high initial planting density of cypress plantations and the construction of pure forests,resulting in the decline of soil fertility,single stand structure and low biodiversity,the multi-functional benefits of plantations are reduced,the ability of forests to absorb carbon dioxide decreases,and their surface carbon pool functions are affected.Forests have become an important part of the global carbon pool,and soils are important places for carbon metabolism,which are significantly affected by the functional taxa of soil microorganisms.As an important management method,the cultivation of edible fungi under the forest changes the forest environment,thereby affecting the functional groups of microbial community structure,and the soil carbon storage may be changed.However,there are limited reports assessing the effect of edible fungus cultivation under cypress funebris forests in the hilly area of central Sichuan on the microbial communities and soil carbon storage.Therefore,in this study,the 25 a cypress plantation in Zitong County,Sichuan Province was taken as the research object,and the edible fungus bags were planted under the cypress forest.Three edible fungus test plots were established,A.morel(Morchella esculenta),B.shiitake mushrooms(Lentinula edodes),C.oyster mushrooms(Pleurotus ostreatus)and CK(without any treatment in cypress forest).After the experimental plot was established in October 2020(before edible fungi were planted),according to measurement of each single wood,the growth index and soil physicochemical properties of the stand were measured.In October of the following year,the above indicators were continued to be measured and metagenomic sequencing were used to obtain soil microbial community composition function and carbon metabolism functional genes,and structural equation model(SEM)was constructed to analyze the interaction and relationship(index)between soil physicochemical properties-microbial community-carbon storage,aiming to explore the influence mechanism of environmental factors and microbial synergy on soil carbon storage,and the main results were as follows:(1)Morel and shiitake mushrooms were planted to promote the growth of chest diameter and crown width in cypress forests,respectively.The diameter of the breast diameter(>14 cm)of cypress plantations planted with shiitake mushrooms was significantly higher than that of the control CK(P<0.05),and the planting of shiitake mushrooms under the forest increased the forest stand stock.Compared with the control,the soil microbial biomass carbon was significantly increased by the cultivation of shiitake and oyster mushrooms under cypress plantation(P<0.05).The soil microbial biomass nitrogen of morels was significantly higher than that of oyster mushroom(P<0.05).The soil urease and invertase activities of morels mushrooms were significantly higher than those of the control(P<0.05),and the catalase activity was the highest in the plot of shiitake mushrooms.Compared with the control,there were significant differences in soil quality moisture content,capillary water holding capacity and field water holding capacity in the plots planted with oyster and shiitake mushrooms(P<0.05).The soil temperature was significantly lower than that of the control(P<0.05).The three edible fungi planted under cypress were closely related to the contents of total phosphorus,total nitrogen and available potassium in the soil(P<0.05).(2)The cultivation of edible fungi under cypress forests had a significant effect on soil microbial community.Compared with the control,the bacterial sequence number(P<0.05)was significantly reduced by the cultivation of the three edible fungi,while the fungal sequence number(P<0.05)was significantly increased by the cultivation of morels.There were significant differences in the Fungus Shannon index,bacteria and archaea Chao1 index in the three edible fungus plots(P<0.05).At the level of the phylum,the dominant bacterial species of the four treatments were proteobacteria,acidobacteria,and actinobacteria,ascomycota occupies an overwhelming position in all fungal treatments,The species composition of morels was quite different from that at the fungal genus and class level compared with other treatments,and the proportion of hyporeales at the class level exceeded50%.The cultivation of edible fungi significantly increased the relative abundance of nitrosocosmicus(P<0.001).Microbial differential species LEFse analysis showed that fungi had the most differential species,followed by archaea and bacteria.(3)After planting three edible fungi,the gene abundance of soil microbial metabolic pathway in KEGG and CAZy databases decreased.The abundance of por A,por C and acl B genes in morel-like plots was significantly increased(P<0.05).The abundance of met F of the anaerobic acetyl Co A pathway decreased significantly after cultivation of edible fungi(P<0.05).Overall,the reduction of tricarboxylic acid cycle pathway after planting edible fungi was significantly improved(P<0.05).mcr A and pmo A were most abundant in shiitake mushroom plots.Compared with the control,the abundance of starch,pectin,hemicellulose,cellulose,chitin and lignin was significantly reduced after planting three edible fungi(P<0.05).(4)SEM analysis showed that urease,available phosphorus and sucrase have a significant impact on carbon metabolism through bacterial and fungal microbial communities;After planting edible fungi,soil carbon storage was significantly increased(P<0.05).Among them,the shiitake mushroom plot has the highest soil carbon storage.The cultivation of edible fungi significantly affected the soil physicochemical properties,followed by the soil physicochemical properties through bacteria,fungi and archaea(P<0.05),while invertase affected soil carbon storage through positive correlation with fungi.In summary,the cultivation of edible fungi significantly affected the growth of DBH and stand volume of cypress forest,changed the species composition of microbial community,and affected the abundance of carbon metabolism functional genes.Understory edible fungi mainly affect the change of soil carbon storage by changing soil physical and chemical properties and microbial community structure,composition and function,and promote the growth of cypress forest.By implementing this fungus-forest composite model management(edible fungi planted under cypress forests),it not only promotes the change of underground microbial community ecosystem,but promotes the growth of aboveground plantations,which helps to improve the functional value of forest ecosystem services,thereby providing scientific basis for the sustainable management of cypress plantations in the hilly area of central Sichuan. |
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