黄土高原沟壑区不同杏树嵌套种植模式对土壤微生物组成的影响

目的]研究黄土高原地区土壤微生物群落结构及其主要生理类群在杏树不同嵌套种植模式中的地位和作用。方法]用"平板培养法"和常规方法,研究了不同嵌套模式下土壤微生物三大类群、主要功能群组成、土壤全氮及有机质含量的变化,并以系统聚类及主成分分析(PCA)等方法进行数据分析。结果](1)土壤微生物总数量及三大类群数量以杏树与紫花苜蓿的嵌套模式最高(p0.05),杏树嵌套黄花菜和紫花苜蓿次之(p0.05),其余嵌套模式间无显著性变化(p0.05);(2)在杏树和紫花苜蓿的模式中土壤固氮菌数量、氨化细菌和纤维素分解菌数量最高(p0.05),杏树和黄花菜和紫花苜蓿嵌套模式次之(p0.05);(3)土壤微生物三大类群中,土壤放线菌数量对Shannon—Wiener指数的大小变化起着较大作用;(4)依据可培养微生物组成,5种嵌套模式可划分为3个类群,嵌套植被对土壤微生物组成的影响不同,紫花苜蓿对土壤微生物学性质的作用更强。结论]杏树在不同嵌套种植模式下土壤微生物群落结构组成与嵌套植被类型关系密切且具有其独特的规律及变化原因。

Effects of Different Nested Planting Modes of Prunus Armeniaca on Soil Microbial Composition in Gully Areas of Loess Plateau

Objective] Studying the status and function of soil microbial-community structure and major functional microbial-groups on different Prunus armeniaca inter-plantation in the Loess Plateau region.Methods] Three groups of soil microorganisms and major functional microbial-groups of soil were investigated based on the method of plate cultivation, and soil total nitrogen and organic matter were measured by conventional method; meanwhile, the dates were analyzed using hierarchical cluster as well as principal component analysis(PCA).Results] (1) As for the total number of soil microorganisms and three major microbial groups, the highest values of them were found in the inter-plantation of P. armeniaca with alfalfa(p<0.05), the values in the inter-plantation of P. armeniaca with daylily and alfalfa times followed(p<0.05), and there was no significant difference among the rest inter-plantation patterns(p>0.05); (2) Soil azotobacter, ammonifier and cellulose decomposing bacteria were all found with the highest numbers in the inter-plantation of P. armeniaca with alfalfa(p<0.05), the second place was taken by numbers of these soil bacterial groups in the inter-plantation of P. armeniaca with lily and alfalfa(p<0.05); (3) The actinomycetes group played a more important role in the changes of Shannon-Wiener index; (4) The five inter-plantations were classified into three patterns according to the composition of cultivable soil microbes using the methods of hierarchical cluster as well as principal component analysis; inter-plantation with alfalfa was found with the greatest effect on the composition of soil microbial community, as compared with other patterns.Conclusion] There were some distinctive and intrinsic interlinks between the variation of soil microbial composition and inter-plantation patterns.