平茬对小叶锦鸡儿灌丛化草原土壤微生物群落的影响  

Effects of pruning on soil microbial community in the Caragana microphylla-encroached grassland

作　　者：郝广 王小平[1] 丁新峰 董轲 杨楠 高韶勃 王金龙 陈磊[1] 何兴东[1] 赵念席[1] 高玉葆[1] HAO Guang;WANG Xiao-ping;DING Xin-feng;DONG Ke;YANG Nan;GAO Shao-bo;WANG Jin-long;CHEN Lei;HE Xing-dong;ZHAO Nian-xi;GAO Yu-bao(College of Life Science,Nankai University,Tianjin 300071,China;College of Agronomy&Resources and Environment,Tianjin Agricultural University,Tianjin 300071,China)

机构地区：[1]南开大学生命科学学院,天津300071 [2]天津农学院农学与资源环境学院,天津300071

出　　处：《生态学杂志》2019年第11期3291-3297,共7页Chinese Journal of Ecology

基　　金：国家重点研发计划项目(2016YFC0500706);国家自然科学基金项目(31770505,31570427)资助

摘　　要：为了明确土壤微生物群落组成和结构对草原灌丛平茬处理的响应,并分析土壤微生物群落组成、结构与土壤理化性质及地上部植物群落的关系,本研究以小叶锦鸡儿灌丛化的退化草原为对象,对小叶锦鸡儿灌丛实施平茬处理并设置未平茬对照,处理3个月后,对两种处理条件下灌丛间植物群落的组成和结构及土壤理化性质进行测定,并运用磷脂脂肪酸(phospholipid fatty acid,PLFA)生物标记法分析两种处理下0~5和15~20 cm土层土壤微生物群落组成和结构。结果显示:(1)与对照相比,平茬样方植物群落地上总生物量有下降趋势,主要表现在褐沙蒿生物量的下降,物种数及Shannon指数显著增加,0~5 cm土壤p H显著降低,而15~20 cm土壤全碳、全氮及碳氮比显著提高;0~5 cm土壤总PLFAs、格兰氏阳性菌(G^+)、格兰氏阴性菌(G^-)、细菌(B)、真菌(F)以及放线菌(Act)PLFAs含量显著增加,G^+/G^-显著降低。(2)冗余分析结果表明,土壤p H与G^+PLFAs含量呈正相关,与G^-、F及Act PLFAs含量呈负相关;土壤全氮与G^+、G^-、F及Act PLFAs含量均呈正相关;Shannon指数与G^+PLFAs含量呈负相关,与G^-、F及Act PLFAs含量呈正相关;地上总生物量与G^-、F及Act PLFAs含量呈负相关。这些结果表明了土壤微生物群落组成和结构能够对草原灌丛平茬处理引起的地上部植物群落及土壤环境条件的变化快速响应,对土壤健康状况具有指示作用,可为内蒙古灌丛化草原的恢复提供科学指导。To examine the response of soil microbial community to pruning of encroaching shrub species and explore the relationships between soil microbial community composition/structure and soil physicochemical properties and plant community,we set up treatment of pruning Caragana microphylla plots and control plots without pruning in the C.microphylla-encroached grassland of Inner Mongolia.Three months later,soil physicochemical properties were measured,composition and structure of plant communities were investigated,and soil microbial community composition and structure at the depths of 0-5 cm and 15-20 cm were analyzed by phospholipid fatty acids(PLFA)method.Compared with control,pruning treatment decreased the total aboveground biomass,with a significant decrease of Artemisia intramongolica biomass,while significantly increased species richness and Shannon index.Soil pH was significantly lower at 0-5 cm layer,and soil total carbon content,total nitrogen content,and C/N were significantly higher at 15-20 cm soil layer.The PLFAs contents of total microbes,Gram-positive bacteria(G+),Gram-negative bacteria(G-),bacteria(B),fungi(F)and actinomyces(Act)were significantly higher,and G+/G-was lower at 0-5 cm layer.Results of redundancy analysis(RDA)showed that soil p H was positively correlated with the PLFAs content of G+,and negatively correlated with that of G-,F and Act.Soil total nitrogen content was positively correlated with PLFA contents of G+,G-,B,F and Act,while Shannon index was negatively correlated with that of G+and positively correlated with that of G-,F and Act.Total aboveground biomass was negatively correlated with the PLFAs contents of G-,F and Act.These results indicated that soil microbial community composition and structure would respond rapidly to the changes of plant community and soil physicochemical properties caused by pruning,which could be used as an indicator for soil health and provide guidance for the restoration of shrub-encroached grassland.

关 键 词：平茬 小叶锦鸡儿 土壤微生物群落 磷脂脂肪酸 

分 类 号：S71[农业科学—林学]