王桂红 何寻阳 苏以荣 徐学池 王小利 冯书珍

摘 要：为明确西南喀斯特退耕还林还草与粮改饲等国家生态工程建设对土壤微生物量的影响，本研究选取广西环江县典型种植模式（玉米与桂牧一号），按土壤发生层采集淋溶层（A层，0～10 cm）、过渡层（AB层，30～50 cm）、淀积层（B层，70～100 cm）样品，利用氯仿熏蒸、實时荧光定量PCR、磷脂脂肪酸（PLFA）等方法研究作物、土层及其交互作用对土壤微生物量的影响及其机制，以期为传统玉米种植到草食畜牧业种植模式的转变提供理论依据。结果表明，作物、土层及其交互作用对土壤微生物生物量碳、真菌遗传丰度及细菌PLFAs量均有显著影响；总体上，土壤微生物生物量与总PLFAs量均表现为随土层加深而降低，但真菌遗传丰度及真菌PLFAs量则表现为B层最高；表层土壤微生物量在两种作物下无显著差异，但桂牧一号地土壤B层细菌PLFAs量显著高于玉米地，而玉米地土壤AB层真菌遗传丰度显著高于桂牧一号地。逐步回归分析表明，全氮、pH、有机质分别影响细菌遗传丰度、总PLFAs量与细菌PLFAs量；速效钾显著影响土壤微生物生物量碳、真菌遗传丰度、总PLFAs量以及真菌PLFAs量。上述结果表明，传统玉米转变为牧草种植模式后更应关注深层土壤微生物群落的变化，同时，喀斯特地区农田土壤钾素对土壤微生物具有重要影响。

关键词：典型作物；土层；土壤微生物生物量；实时荧光定量PCR；PLFA

中图分类号：X171

文献标识码：A

文章编号：1008-0457（2018）04-0051-007 国际DOI编码：10.15958/j.cnki.sdnyswxb.2018.04.008

Study on Different Land Uses and Soil Layers on Soil Microbial Biomass Distribution of Maize and Guimuyihao

WANG Guihong1，2，HE Xunyang2，3，SU Yirong2，3，XU Xuechi2，4，WANG Xiaoli1*，FENG Shuzhen5*

（1.College Agriculture， Guizhou University， Guiyang， Guizhou 550025， China； 2. Key Laboratory of Agro-ecological Processes in Subtropical Region， Institute of Subtropical Agriculture， Chinese Academy of Sciences， Changsha， Hunan 410125， China； 3. Huanjiang Observation and Research Station for Karst Ecosystems， Chinese Academy of Sciences， Huanjiang， Guangxi 547100， China； 4. University of Chinese Academy of Sciences， Beijing 100049， China； 5.Medical College of Guangxi University of Science and Technology， Liuzhou， Guangxi 545006， China）

Abstract：The aim of present paper is to clarify the impact of national ecological-engineering reconstruction such as returning farmland to forestry and grassland and replacing grain crops with pasture on the soil microbial biomass in the southwest karst areas. The study was undertaken in Huanjiang County， Guangxi Province， an area with the typical planting patterns of corn and pasture. Samples of leaching were collected from different soil layers： top layer（A，0～10 cm）， transitional layer （AB，30～50 cm） and alluvial layer （B，70～100 cm）. Chloroform fumigation extraction methods，real-time fluorescence-based quantitative PCR （Real-time PCR） and phospholipids fatty acid（PLFA）were adopted to evaluate the impact of different land uses and soil layers and their interactions on soil microbial biomass. The study could provide a theoretical basis for the transformation of the traditional corn cultivation to herbivorous animal husbandry. The results showed that crops and soil layers and their interactions had significant impact on soil microbial biomass carbon， fungal genetic abundance and bacterial PLFAs.On the whole， the soil microbial biomass and total PLFAs were decreased with the deepening of soil layers； however， the fungal genetic abundance and fungal PLFAs were highest in layer B.There was no significant difference in topsoil microbial biomass between the corn planting and pasture； however， the bacterial PLFAs in layer B of grassland was significantly higher than that in corn field， the fungal genetic abundance of AB layer in corn field was significantly higher than that in grassland.Stepwise regression analysis showed that the total nitrogen， pH and organic matter affected bacterial genetic abundance， total PLFAs and bacterial PLFAs， respectively. Available potassium significantly affected soil microbial biomass carbon， fungal genetic abundance， total PLFAs and fungal PLFAs. These results indicate that the transformation of traditional maize into pasture should pay more attention to the changes of the deep soil microbial community. At the same time， in karst area，farmland soil potassium has important influence on soil microbes.

Key words：typical crop planting patterns； soil layer； soil microbial biomass； real-time PCR； PLFA

中国西南喀斯特地区生态环境脆弱，人口―资源―环境的矛盾日益突出，强烈的人为干扰导致土地质量的下降与石漠化，制约着该地区的可持续发展。……