宁夏引黄灌区不同土地利用方式土壤微生物群落多样性研究

以宁夏引黄灌区6种典型利用方式(12年果园田、稻旱轮作田、盐化旱田、枸杞田、常年旱田、常年稻田)灌淤土为研究对象,通过同期野外多点采样和室内培养分析相结合,运用磷脂脂肪酸谱图分析方法,探讨了不同土地利用与管理方式下灌淤土理化性质、微生物生物量、微生物区系及微生物群落多样性差异及相关关系,以期为宁夏引黄灌区土壤可持续利用提供数据支撑。结果表明,(1)不同土地利用方式中,长期秸秆还田的盐化旱田、长期有机无机配施的12年果园以及常年旱田3种利用方式下,土壤地力水平较高,相应土壤微生物生物量炭、氮水平最高,有利于土壤微生物数量的保持,而常年淹水条件下的常年稻田土壤肥力水平低下,微生物生物量最低。(2)不同土地利用方式磷脂脂肪酸PLFA总量变幅为81.1-94.8 nmol·g^?1,其中盐化旱田>12年果园>稻旱轮作>常年旱田>枸杞园>常年稻田;好氧细菌14:0、16:0和18:0比例最大,革兰氏阳性细菌16:0iso在12年果园、稻旱轮作田中含量显著提高,放线菌次之,而真菌18:3ω6c在12年果园、盐化旱田、稻旱轮作3种利用方式下含量升高。(3)相关分析表明,引黄灌区土壤磷酸脂肪酸与土壤pH、微生物量碳及微生物量磷之间呈极显著正相关,与土壤有机质呈显著正相关;主成分分析表明,盐化旱田和12年果园具有相近的微生物群落结构。(4)综上所述,有机无机配施常年果园和秸秆还田常年旱田是适用于该地区的土地利用与管理方式。

Soil Microbial Biomass and Activity in Different Land Use Types in Ningxia Irrigation Area

Six typical utilization methods of fill soil in Ningxia irrigation area,including 12-year’s orchard field,rice crop rotation field,saline dry field,Chinese wolfberry field,perennial dry field and perennial rice field are studied via combining of the simultaneous outdoor multipoint sample and indoor culture analysis.By using the spectrogram analysis method of phospholipid fatty acids,the differences and correlation in physicochemical properties,microbial biomass,microbial flora and microbial community diversity of fill soil under different land utilization and management methods are discussed in order to provide data support for soil sustainable utilization in Ningxia irrigation area.Results show that:(1)In three different ways of land utilization,for instance,long-term straw returned of saline dry field,the 12-year’s of long-term organic and inorganic fertilizer orchard and perennial dry field,the soil fertility level is higher,and the corresponding soil microbial biomass carbon and nitrogen levels are the highest,which is conducive to the maintenance of soil microbial quantity.Moreover,the soil fertility level is low and the microbial biomass is the lowest under the condition of perennial flooding.(2)The variation of total phospholipid fatty acid PLFA in different land use patterns range at 81.1?94.8 nmol·g^?1,among them,the saline upland>12-year’s orchard>rice drought rotation field>perennial upland>Chinese wolfberry orchard>perennial rice field.The proportion of aerobic bacteria including 14:0,16:0 and 18:0 is the largest,and the gram-positive bacteria 16:0ISO content is significantly increased in 12-year’s orchard and rice dry rotation field,followed by actinomycetes,while the content of fungus 18:3w6c is increased in 12-year’s orchard,saline dry field and rice dry rotation filed.(3)According to correlation analysis,the soil phosphoric acid shows an extremely significant positive correlation with soil pH,microbial biomass carbon,and microbial biomass phosphorus,as well as a significant positive correlation with soil organic matter.Furthermore,the saline dry field and 12-year’s orchard indicate a similar microbial community structures on the basis of principal component analysis(PCA).And(4)in summary,the application of organic and inorganic fertilizer in perennial orchard and straw recycling model in perennial dry field is appropriate for the land utilization and management methods in this area.