玉米秸秆生物炭对天人菊土壤理化性质及根际土壤真菌群落结构的影响

Effects of corn stalk biochar on soil physicochemical properties and fungal community structure in the rhizosphere of Gaillardia pulchella Foug.

【目的】明确玉米秸秆生物炭对天人菊土壤养分含量、酶活性和根际真菌群落等环境因子变化规律的影响及其作用机制,为提高玉米秸秆的资源化利用提供理论依据。【方法】在盆栽天人菊土壤中分别施入20、40、60和80 g/kg的玉米秸秆生物炭,以不添加玉米秸秆生物炭处理为对照(CK),于盛花期测定各处理天人菊根际土壤的速效养分(速效磷、速效钾、碱解氮和有机质)含量及过氧化氢酶(CAT)和脲酶活性,采用高通量测序技术测定根际土壤真菌群落多样性,并分析玉米秸秆生物炭作用下天人菊根际土壤理化性质与土壤真菌群落结构间的相关性。【结果】与CK相比,土壤中施入20~60 g/kg玉米秸秆生物炭可显著提高天人菊根际土壤速效磷含量(P<0.05,下同),极显著提高速效钾、碱解氮和有机质含量(P<0.01,下同);在土壤酶活性方面,土壤中施入20~80 g/kg玉米秸秆生物炭对CAT活性无显著影响(P>0.05,下同),施入40 g/kg玉米秸秆生物炭极显著提高脲酶活性,但施入量达80 g/kg时极显著降低脲酶活性。即玉米秸秆生物炭能有效改变天人菊根际土壤理化性质,且以施入40 g/kg的效果最佳。施入玉米秸秆生物炭能调控天人菊根际土壤的真菌群落结构,也是以施入40 g/kg的真菌物种相对丰度较高,生物炭作用效果最明显。在门分类水平上,各玉米秸秆生物炭处理天人菊根际土壤真菌群落结构中以子囊菌门(Ascomycota)为绝对优势菌门,其次是担子菌门(Basidiomycota)、接合菌门(Zygomycota)、壶菌门(Chytridiomycota)和球囊菌门(Glomeromycota);在科分类水平上,优势菌科为子囊菌门的6个科[毛壳菌科(Chaetomiaceae)、小囊菌科(Microascaceae)、丛赤壳科(Nectriaceae)、毛球壳科(Lasiosphaeriaceae)、子囊菌科(Ascomycoceae)和毛孢壳科(Coniochaetaceae)]及接合菌门的被孢霉科(Mortierellaceae),且毛壳菌科、小囊菌科、从赤壳科、子囊菌科、被孢霉科及毛孢壳科等6个根际土壤优势菌科均表现为各玉米秸秆生物炭处理的相对丰度明显高于CK。天人菊根际土壤理化特性指标与子囊菌门和接合菌门及子囊菌科、被孢霉科和毛孢壳科的相对丰度密切相关。【结论】玉米秸秆生物炭可活化天人菊根际土壤理化性质及酶活性,改变土壤真菌群落结构,进而提高土壤肥力,其中以施入40 g/kg玉米秸秆生物炭的作用效果最佳,可在生产上推广应用。

【Objective】To clarify the effects of corn stalk biochar treatment on the changes of environmental factors such as soil nutrient content,enzyme activity and rhizosphere fungus community in Gaillardia pulchella Foug.and its mechanism,and provide theoretical basis for the utilization of corn stalk.【Method】Applied 20,40,60 and 80 g/kg corn stalk biochar into the soil of potted G.pulchella.Used no corn stalk biochar treatment as control(CK),and measured contents of available nutrients(available phosphorus,available potassium,alkali-hydrolyzable nitrogen and organic matter)and the activities of catalase(CAT)and urease in rhizosphere soil of G.pulchella during the full bloom period.Highthroughput sequencing technology was used to determine the fungal community diversity in rhizosphere soil,and the correlation between the physical and chemical properties of the rhizosphere soil and soil fungal community structure under the action of corn stalk biochar was analyzed.【Result】Compared with CK treatment,applying 20-60 g/kg corn stalk biochar into the soil could significantly increase the content of available phosphorus in the rhizosphere soil of G.pulchella(P<0.05,the same below),and extremely significantly increase available potassium,alkaline nitrogen and organic matter content(P<0.01,the same below).In terms of soil enzyme activity,the application of 20-80 g/kg corn stalk biochar in the soil had no significant effect on CAT activity(P>0.05,the same below).Application of 40 g/kg corn stalk biochar extremely significantly increased urease activity,but application of 80 g/kg corn stalk biochar extremely significantly reduced urease activity.That was to say,corn stalk biochar could effectively change the physical and chemical properties of the rhizosphere soil of G.pulchella,and the effect of 40 g/kg was the best.The application of corn stalk biochar could regulate the fungal community structure in the rhizosphere soil of G.pulchella,and the relative abundance of fungal species at 40 g/kg was higher,and the effect of biochar was the most obvious.At the level of phyla classification,Ascomycota was the absolute predominance in the structure of the fungal flora in the rhizosphere soil of the corn stalk biochar treatment,followed by Basidiomycota,Zygomycota,Chytridiomycota and Glomeromycota.At the level of family classification,the dominant family of bacteria were six families of Ascomycota:Chaetomiaceae,Microascaceae,Nectriaceae,Lasiosphaeriaceae,Ascomycoceae,Coniochaetaceae,and Mortierellaceae of the phylum Mortierellaceae.In the all six dominant bacteria families(Lasiosphaeriaceae,Microascaceae,Nectriaceae,Ascomycoceae,Mortierellaceae and Coniochaetaceae)in rhizosphere soils,the relative abundance of each corn stover biochar treatment was higher than that of CK treatment.The physicochemical characteristics of the rhizosphere soil of G.pulchella were closely related to the relative abundance of Ascomycota and Zygomycota,Ascomycocaceae,Mortierellaceae and Chaetomium.【Conclusion】Corn stalk biochar can activate the physicochemical properties and enzyme activity of the rhizosphere soil of G.pulchella,change the structure of soil fungi community,and improve soil fertility.Among them,40 g/kg corn stalk biochar has the best effect,and can be promoted and applied in production.