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化肥减施对茶园土壤真菌群落结构和功能类群的影响

Effects of Reduced ChemicalFertilizer Applications on Fungal Community and Functional Groups in Tea PlantationSoil

  • 摘要: 为揭示不同化肥减施模式对茶园土壤真菌群落结构和功能类群的影响,以武夷山水仙茶园为研究对象,设置不施肥(CK)、当地常规施肥(CF)、有机替代(OF,化肥减量50.7%)、新型缓释肥(SRF,化肥减量34.4%)和茶树专用生物炭基肥(BF,化肥减量30.3%)5个处理。利用Illumina Miseq 高通量测序技术和 FUNGuild 对茶园土壤真菌群落结构和功能类群进行分析。结果表明:茶园土壤真菌群落主要由子囊菌门(Ascomycota)和担子菌门(Basidiomycota)主导,分别占42.24%~48.79%和21.65%~36.11%。与CF处理相比,OF和BF处理的球囊菌门(Mortierellomycota)相对丰度显著增加(P<0.05),OF处理的担子菌门相对丰度显著降低(P<0.05),其他菌门变化不显著。在纲水平上,与CF处理相比,OF处理的微球黑粉菌纲相对丰度显著降低(P<0.05),伞菌纲相对丰度显著增加(P<0.05),BF处理的被孢霉纲相对丰度显著降低(P<0.05),5个处理间其它菌纲差异不显著。有机替代施肥模式的Sobs和Shannon指数均高于常规施肥处理(P<0.05),其余处理之间差异不显著(P>0.05)。不同施肥模式之间真菌的营养类型以腐生营养型为主(37.74 %~61.56%)。与CF处理相比,由于加入新的有机质,有机替代模式土壤病理营养型真菌相对丰度显著降低了37.72%,腐生营养型真菌相对丰度则显著提高42.27%,增加主要以内生-垃圾腐生-土壤腐生-未定义腐生真菌、外生菌根-真菌寄生菌和真菌寄生菌为主,这有利于降低茶园中土传病害风险。冗余分析结果显示,施肥后土壤有机质和速效钾变化是驱动茶园土壤真菌群落结构和功能类群组成的主要因子。总体而言,长期单施化肥会降低真菌种群多样性,有机无机肥配施可在一定程度上提高真菌多样性和腐生真菌比例,降低土壤病理营养型真菌相对丰度,有利于保持茶园土壤生态系统健康。

     

    Abstract: Characteristics of fungalcommunity and functional groups in the soil at tea plantations in Wuyishan Cityunder various treatments designed to reduce the use of chemical fertilizers werestudied. Illumina high-throughput sequencing and FUNGuild were employed todetermine the fungal community structure and functional group composition. Thefertilization treatments included applications of non-fertilizer (CK),conventional fertilization (CF), organic fertilizer replacement (OF, with a50.7% reduction on chemical fertilizer), slow release fertilizers (SRF, with a34.4% reduction on chemical fertilizer), and biochar-based formula fertilizer(BF, with a 30.3% reduction on chemical fertilizer). At phylum level,Ascomycota and Basidiomycota accounting for 42.24-48.79% and 21.65-36.11%of total, respectively, were the dominant fungi inthe community. Compared to CF, OF and BF produced significantly higher relativeabundance on Mortierellomycota (P<0.05), and OF significantly loweron Basidiomycota (P<0.05). There were nosignificant differences on other phyla and classes among the soils under the 5treatments. At class level, the relative abundance of Microbotryomycetes underOF was significantly lower than that under CF, but the proportion ofAgaricomycetes significantly higher (P<0.05). The relative abundanceof Mortierellomycetes only was higher under BF than under CF. The diversityindices including Sobs and Shannon were all significantly increased by OF overCF. Saptrotroph was identified as the dominant trophic group in the soils at 37.74-61.56%of total. Compared to CF, OF significantly reduced the proportion of pathotrophgroup by 37.72% due to the addition of organic matters. The increase by 42.27%on the proportion of saprotroph fungi (i.e., mainlythe endophyte-litter saprotroph-soil saprotroph-undefined saprotrophs,ectomycorrhizal-fungal parasites, and fungal parasites) materially alleviatedthe risk of disease spreading at the plantations. A redundancyanalysis attributed organic matters and available potassium in soil to bethe major factors that affected the fungal community structure and functional groups.It appeared that the alpha diversity and abundance index of soil fungi slightlydeclined by chemical fertilization, on the other hand, the incorporation oforganic fertilizer would help maintain a healthy ecosystem in the soil at teaplantations with the increased fungal diversity and proportion of saprotrophs.

     

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