Research On Community Structure And Soil Microbial Diversity During Recovery Process Of Degraded Masson Pine (Pinus Massoniana) Forest

Masson pine is one of the important timber tree species in southern China.However,the masson pine forest has been affected by a large area of pine wood nematode disease in recent years,resulting in the death of plants in the masson pine forest.Regeneration of degraded Pinus massoniana forest after nematode disturbance.Therefore,carrying out research on the restoration of degraded masson pine forest has become an important research topic in the discipline of forest cultivation and ecology.In this study,the degraded forest of Pinus massoniana formed in Wanling Forest Farm of Xuanzhou District,Xuancheng District,Anhui Province was selected as the research object,and a community structure survey during the restoration process of degraded Masson pine forest was carried out.The Guideline divides the degradation degree of degraded forest,analyzes the community structure characteristics and species diversity of Pinus massoniana forests with different degrees of degradation,and samples the soil to analyze the physical and chemical properties and the characteristics of soil microbial diversity.Recovery provides theoretical basis and practical guidance.(1)There are three types of Pinus massoniana forest.In this survey,1074 surviving woody individuals with DBH?3cm were recorded,which were divided into 15 families,17 genera and 19 species;the number of shrub layer species was 32,divided into 24 families and 29 genera;There are fewer species in the strata,which belong to 6 families and 4 genera,a total of 7 species.The three different types of Pinus massoniana forests can be divided into three levels in the vertical direction: tree,shrub,and grass.Holly and sassafras wood have obvious dominance in heavily degraded and moderately degraded masson pine tree layers.(2)The Shannon-Winer and Simpson indices of severely and moderately degraded Masson pine forests are both: arbor layer>shrub layer>herb layer,in mildly degraded forests are: shrub layer>herb layer>arbor layer rule,severe The Simpson index of degraded and moderately degraded was significantly higher than that of mildly degraded masson pine forest.The important values of the main tree species in the tree layer are: the heavily degraded forest in the Wood(33.97)>Masson pine(29.66)>wintergreen(17.15),and the moderately degraded forest: the Masson pine(45.07)>Wood(26.17)>Wintergreen(11.91),mildly degraded forest: Masson pine(87.51)>Holly(5.67),indicating that Holly and Coatwood can adapt to local climate,soil and other environmental factors,as the main broad-leaved tree species recovered under the forest.(3)Ammonia nitrogen,total P,total TC,and TN in the soil all decrease with the deepening of the soil layer.Total N and water content are different in heavy,moderately and slightly degraded Masson pine forests,and the soil nutrient content is basically The severely and moderately degraded masson pine forest was higher than the mildly degraded masson pine forest,in which the total N content of the heavily degraded masson pine forest in the 0-20 cm soil layer was 20.91g/kg,the moderate degradation was 23.75g/kg,and the mild degradation was only 12.91g/kg;generally speaking,the two soil layers showed a significant correlation between vegetation diversity and nitrate nitrogen,total P,total C and DOC in slightly degraded masson pine forest,and total P and total C in soil in severely and moderately degraded masson pine forest And DOC content had the most obvious effect on the vegetation diversity in the community.(4)The AWCD values of severely and slightly degraded Masson pine forests were higher than those of moderately degraded Masson pine forests;the Shannon-Winer diversity index of soil microorganisms was higher,with severe degradation being 2.88,moderate degradation being 3.02,and mild degradation being 3.13;the correlation between soil microbial diversity and vegetation diversity in severely and moderately degraded Pinus massoniana forests;the utilization rate of six types of carbon sources in the severely and moderately degraded Masson pine forests and the average absorbance of soil microorganisms AWCD and trees The three diversity indexes in the layer,shrub layer,and herb layer all showed insignificant negative correlations.In the slightly degraded masson pine forest,only polymers and polyphenols had insignificant negative correlations;In moderately degraded masson pine forests,total P and N in soil nutrients showed significant positive correlations with soil microbial diversity index and vegetation diversity index(P<0.05);in mildly degraded masson pine forests,total P and DOC also There is a significant positive correlation with soil microbial diversity index and vegetation diversity index(P<0.05).