1、红壤有机碳组分中微生物群落构成及均匀度决定其矿化特征红壤有机碳组分中微生物群落构成及均匀度决定其矿化特征单会茹1,2，张璐2，高强1，段英华2*，徐明岗2*（1吉林农业大学资源与环境学院，吉林长春130118；2中国农业科学院农业资源与农业区划研究所/农业农村部耕地质量监测与评价重点实验室，北京100081）摘要:【目的目的】有机碳矿化是陆地碳循环的关键环节，探究长期不同施肥下有机碳组分的矿化特征及其微生物学响应，以明确有机碳在土壤中的固存过程和损失机制。【方法方法】选取中国农业科学院祁阳红壤肥力长期试验的撂荒(CK0)、不施肥对照(CK)、氮磷钾化肥配施(NPK)和化肥配施有机肥(NPKM)
2、4 个处理，通过物理分组方法获得粗颗粒有机碳(cPOC)、细颗粒有机碳(fPOC)、团聚体内颗粒有机碳(iPOC)和矿物结合态有机碳(MOC)。以该 4 个处理的有机碳组分进行室内培养试验，研究有机质的矿化动态。采用磷脂脂肪酸(PLFA)方法测定各组分中的微生物量及组成，再利用冗余分析明确微生物群落特征对有机碳矿化的贡献。【结果结果】长期施肥显著提升了红壤总有机碳水平，显著提高了活性有机碳组分(cPOC、fPOC、iPOC)的占比。有机碳组分的矿化速率表现出明显的阶段性特征：前期(矿化 135 天)矿化迅速，后期逐渐变缓并趋于平稳。各组分平均最大矿化速率和累积矿化量均表现为 fPOCcPOCi
3、POCMOC，表明 fPOC 组分的活性最高，可矿化性最强。与CK 相比，CK0处理的 cPOC、fPOC、iPOC 和 MOC 组分最大矿化速率分别提高了 158.0%、36.4%、67.3%和146.0%；NPK 处理的 4 个组分有机碳的矿化速率与 CK 无显著差异；NPKM 处理分别提高了 246.0%、62.9%、21.4%和 183.0%。土壤有机碳组分快速矿化阶段(矿化 15 天)的总 PLFA 生物量表现为 fPOC 最高，平均为 94.5nmol/g，约为其他组分(平均 26.135.0nmol/g)的 3 倍。各组分中革兰氏阳性菌/革兰氏阴性菌(G+/G)比例表现为 MOC
4、(6.06)cPOC(5.18)fPOC(1.26)iPOC(1.03)，平均真菌/细菌(F/B)为 iPOC(0.11)fPOC(0.10)MOC(0.06)cPOC(0.03)，fPOC 和 iPOC 组分 F/B 值较高而 G+/G值较低，且二者的微生物群落多样性指数都高于其他组分，表明二者群落结构更稳定，所受养分胁迫较少，群落多样性高。冗余分析表明，微生物群落特征对组分矿化的总解释率达 96.4%，其中总 PLFA 含量、真菌、革兰氏阴性菌是对有机碳组分矿化影响最大的 3 个因素。【结论结论】土壤有机碳的可矿化程度与微生物群落结构及群落的物种均匀度密切相关。长期施肥尤其是有机无机肥配施
5、，提高了活性组分中的微生物量，因此提高了土壤中可矿化碳的比例，加之有机肥直接为土壤养分循环提供了额外的能量来源，促进了有机碳的矿化，这可能是施用有机肥提高土壤肥力的原因之一。关键词:红壤；土壤有机碳组分；有机无机肥配施；有机碳矿化；微生物群落结构；物种均匀度Microbial community composition and species uniformity regulate themineralization characteristics of organic carbon fractions in red soilSHANHui-ru1,2,ZHANGLu2,GAOQiang1,D
6、UANYing-hua2*,XUMing-gang2*(1 College of Resources and Environment,Jilin Agricultural University,Changchun,Jilin 130118,China;2 Institute of AgriculturalResources and Regional Planning,Chinese Academy of Agricultural Science/Key Laboratory of Arable Land Quality Monitoringand Evaluation,Ministry of
7、Agriculture and Rural Affairs,Beijing 100081,China)Abstract:【Objective】Terrestrialcarboncycleisdependentonthemineralizationoforganiccarboninsoil.Weexploredthemineralizationcharacteristicsoforganiccarboncomponentsandtheirmicrobiologicalresponsestoclarifytheturnoverprocessofsoilorganiccarbon.【Methods】
8、Theresearchwasalong-termexperimentconductedontheredsoilofQiyangExperimentalStationofChineseAcademyofAgriculturalSciences.The植物营养与肥料学报2023,29(1):109119doi:10.11674/zwyf.2022224JournalofPlantNutritionandFertilizershttp:/www.plantnutrifert.org收稿日期：20220427接受日期：20220721基金项目：国家重点研发计划项目（2021YFD1900300）；国家
9、自然科学基金项目（41620104006）。联系方式：单会茹E-mail:*通信作者段英华E-mail:；徐明岗E-mail:testedsoilsampleswerecollectedfromfourtreatments-fallow(CK0),nofertilizationcontrol(CK),NPKchemicalfertilizers(NPK),andNPKwithorganicfertilizers(NPKM).Firstly,aphysicalgroupingmethodwasusedtodividethetotalorganiccarbon(OC)intofourfractio
10、ns,ascoarse-particleorganiccarbon(cPOC),fine-particleorganiccarbon(fPOC),intra-microaggregate-particleorganiccarbon(iPOC),andmineral-associatedorganiccarbon(MOC).Then,chamberculturemethodwasusedtodeterminethemineralizationdynamicsofthefourfractions,andphospholipidfattyacid(PLFA)methodwasusedtodeterm
11、inethemicrobialbiomassandcomposition.Finally,redundancyanalysiswasemployedforthecontributionofmicrobialcommunitycharacteristicstotheorganiccarbonmineralization.【Results】Long-termfertilizationsignificantlyincreasedtheproportionofactiveorganiccarbonfractions(cPOC,fPOC,iPOC).Themineralizationrateofallt
12、hefourfractionswashighintheearly135days,andgraduallysloweddownuntilstabilized.ThemaximummineralizationrateandcumulativemineralizationamountofeachfractionwereinorderfPOCcPOCiPOCMOC,indicatingthatthefPOChadthehighestactivity.ComparedwithCK,CK0increasedthemaximummineralizationratesofcPOC,fPOC,iPOC,andM
13、OCby158.0%,36.4%,67.3%and146.0%,respectively;NPKtreatmentdidnotaffecttheseindicessignificantly;whileNPKMtreatmentincreasedthemby246.0%,62.9%,21.4%,and183.0%,respectively.fPOCexhibitedthehighesttotalPLFAbiomassattherapidmineralizationstage(94.5nmol/g),whichwasabout3timesofotherfractions(26.135.0nmol/
14、g).TheratioofGram-positivebacteriatoGram-negativebacteria(G+/G)ineachfractionwasMOC(6.06)cPOC(5.18)fPOC(1.26)iPOC(1.03),andtheaverageratiooffungitobacteria(F/B)wasiPOC(0.11)fPOC(0.10)MOC(0.06)cPOC(0.03),thefPOCandiPOChadhigherF/BratioandlowerG+/Gratio,andhigherdiversityindexthantheothertwofractions,
15、indicatingamorestablecommunitystructure,lessnutrientstressandhighcommunitydiversity.Redundancyanalysisshowedthatmicrobialfactors,totalPLFA,fungal,andGram-negative,accountedfor96.4%ofthefractionalmineralizationdifferences.【Conclusions】Themineralizationdegreeofsoilorganiccarboniscloselyrelatedtothemic
16、robialcommunitystructureandspeciesuniformityofthecommunity.Long-termfertilization,especiallywithNPKMtreatmentincreasedthemicrobialbiomassofactiveorganiccarbonfractions,andtheextraenergysourceinput(comparedtoNPK)exaggeratedthemineralizationoforganiccarbon.Thismaybeoneofthereasonsforthecomplementaryapplicationoforganicfertilizerstoimprovesoilfertility.Key words:redsoil;soilorganiccarbonfraction;chemicalandorganicfertilizer;organiccarbonmineralization;microbialcommunitystructure;microbialuniformity