六盘山生态移民迁出区不同植被恢复模式土壤微生物功能多样性研究

Effects of Different Vegetation Restoration Models on Soil Microbial Functional Diversity in Eco-emigration Area of Liupan Mountains

为了揭示宁夏六盘山生态移民迁出后,不同植被恢复模式下土壤微生物群落功能多样性的变化特征,以泾源县移民区6种人工混交林(青海云杉Picea crassiflolia+油松Pinus tabuliformis+河北杨Populus hopeiensis、刺槐Robinia pseudoacacia+油松、旱柳Salix matsudana+刺槐+山杏Prunus armeniaca、油松+山杏、刺槐+山杏+紫花苜蓿Medicago sativa、油松+旱柳+红豆草Onobrychis viciaefolia)为对象,自然恢复为对照,采用Biolog-ECO微平板法研究不同植被恢复模式土壤微生物功能多样性特征。结果表明,(1)7种不同植被恢复模式0～20 cm土层土壤微生物AWCD值以刺槐+山杏+紫花苜蓿模式为最高(0.94±0.44),青海云杉+油松+河北杨最低(0.26±0.18)。(2)不同植被恢复模式土壤微生物对各碳源的利用状况有所差异,碳水化合物类是7种植被恢复模式土壤微生物利用的主要碳源,其次为氨基酸类、羧酸类和聚合物类,而其他化合物和胺类的利用较低。(3)7种不同植被恢复模式土壤微生物多样性指数均存在显著性差异(P<0.05),其中刺槐+山杏+紫花苜蓿和油松+山杏混交林土壤微生物Shannon指数、Brillouin指数和Pielou均匀度指数显著高于其他植被恢复模式(P<0.05)。(4)PCA分析显示,PCA1和PCA2分别占总方差的36.54%和26.83%。刺槐+山杏+紫花苜蓿、油松+山杏、油松+旱柳+红豆草混交模式及自然恢复可利用碳源较多,旱柳+刺槐+山杏混交模式次之,青海云杉+油松+河北杨和刺槐+油松混交模式可利用碳源少。以上结果表明,人工林的不同混交模式对提高土壤微生物群落的代谢活性具有显著差异。该研究区内,刺槐+山杏+紫花苜蓿植被恢复模式较其他植被恢复模式更有利于土壤微生物群落功能多样性的提高。

In order to understand the effect of different vegetation restoration models on functional diversity of soil microbial communities,six mixed plantation forests(Picea crassifolia+Pinus tabulaeformis+Populus hopeiensi,Robinia pseudoacacia+Pinus tabulaeformis,Salix matsudana+Robinia pseudoacacia+Armeniaca sibirica,Pinus tabulaeformis+Armeniaca sibirica,Robinia pseudoacacia+Armeniaca sibirica+Medicago sativa,Pinus tabulaeformis+Salix matsudana+Onobrychis viciaefolia)in the eco-emigration area of Jingyuan County were planted,and the natural recovery was the CK.Biolog-ECO microplates were utilized to study the functional diversity of soil microbial community in different vegetation restoration models.The results showed that the most and lest AWCD values of soil microbes in different vegetation restoration models were Robinia pseudoacacia+Armeniaca sibirica+Medicago sativa(0.94±0.44)and Picea crassifolia+Pinus tabulaeformis+Populus hopeiensis(0.26±0.18).In seven different vegetation restoration models,soil microorganisms had different utilization rates of carbohydrates,amino acids,carboxylic acids,polymers,other mixtures and amines.Carbohydrates were the major carbon sources of soil microbes in seven types of vegetation restoration models,followed by amino acids,carboxylic acids and polymers,while the utilization of other compounds and amines was low.There were significant differences(P<0.05)in Shannon index,Brillouin index and Pielou evenness index of soil microbial communities among different vegetation restoration models.The soil microbial Shannon index,Brillouin index and Pielou average evenness index of Robinia pseudoacacia+Armeniaca sibirica+Medicago sativaand,Pinus tabulaeformis+Salix matsudana+Onobrychis viciaefolia were significantly higher than other vegetation restoration models(P<0.05).PCA analysis showed that PCA1 and PCA2 explained the 36.54%and 26.83%of total variance,respectively.Robinia pseudoacacia+Armeniaca sibirica+Medicago sativa,Pinus tabulaeformis+Armeniaca sibirica,Pinustabulaeformis+Salix matsudana+Onobrychis viciaefolia and natural recovery had more carbon sources utility,Salix matsudana+Robinia pseudoacacia+Armeniaca sibiricahad less carbon sources utility.And Picea crassifolia+Pinus tabulaeformis+Populus hopeiensis and Robinia pseudoacacia+Pinus tabulaeformis had the least carbon source utility.It suggested that it was potential to improve the metabolic activity of the soil microbial community by artificial vegetation restoration.In Liupan mountainseco-emigration area,Robinia pseudoacacia+Armeniaca sibirica+Medicago sativa model is suggested to improve the functional diversity of soil microbial community.