摘要
【目的】真菌在根际土壤养分循环中发挥重要作用,探究磷肥施用方法对甘薯根际土壤真菌群落的影响,以减少施肥可能对甘薯根际土壤微生态环境的不利影响。【方法】甘薯–小麦轮作长期肥料定位试验位于江苏南京,始于2011年。2020年选择该定位试验中的3个处理:不施磷肥(NK)、单施化肥(NPK)和有机无机肥配合(NPKM),在甘薯膨大期采集储藏根与纤维根根际土壤,测定化学性质,并利用Illumina Novaseq高通量测序技术,分析真菌群落相对丰度、群落组成与多样性,及其与根际土壤化学性质的关系。【结果】1)施肥处理改变了两类根根际土壤化学性质,储藏根和纤维根的根际土壤有机碳、溶解性有机碳、速效钾含量均表现为NPKM>NPK>NK处理,有效磷(AP)含量表现为NPK>NPKM>NK (P<0.05),同一处理两类根际间只有有效磷含量差异显著;纤维根和储藏根的根际土壤pH均以NPKM处理最高,NPK处理最低且显著低于NK处理,NPKM处理的纤维根根际pH显著高于储藏根根际0.81个单位。2) 3个施肥处理两类根系根际土壤的优势真菌类群均为子囊菌门(Ascomycota, 70.2%~77.9%)、担子菌门(Basidiomycota, 5.9%~8.5%)和被孢霉门(Mortierellomycota, 1.8%~8.1%)。3个处理间储藏根根际土壤子囊菌门的相对丰度无显著差异,而NK处理纤维根根际土壤子囊菌门的相对丰度显著高于NPKM处理(P<0.05);担子菌门和被孢霉门的相对丰度在NPK和NPKM处理间以及两类根系的根际土壤间均无显著差异,而NK处理的储藏根根际土壤担子菌门和被孢霉门的相对丰度较NPK处理分别低70.4%和62.9%,较NPKM处理分别降低44.0%和151%(P<0.05)。3) NPKM和NPK处理储藏根根际特有的真菌OTUs数分别为122和113个,而NK处理为86个,远低于NPKM和NPK处理。NPKM处理纤维根根际特有的真菌OTUs数最高(160个),而NPK和NK处理分别为114和127个。NK处理的纤维根根际土壤观察到的物种数和Shannon多样性指数显著高于储藏根(P<0.05),NPKM处理两类根际的观察到的物种数和Shannon指数在3个处理中最高。拓扑网络分析表明,储藏根根际土壤真菌类群关系较纤维根根际的更为复杂,而纤维根根际土壤真菌群落具有更强的相互作用关系。冗余分析(RDA)结果表明,根际土壤有效磷、有机碳含量和pH与根际土壤真菌群落结构显著相关(P<0.05)。【结论】长期施用磷肥降低了甘薯两类根际土壤的pH,但显著提高了有机碳、有效磷和速效钾含量,磷肥配施有机肥还避免了pH的降低,因而较单施化肥更有效地提高了根际土壤的真菌数量和多样性。
【Objectives】Fungi play an important role in rhizosphere soil nutrient cycling.Effects of long-term phosphorus fertilizer application on the soil fungal communities in sweet potato rhizosphere were explored,in order to diminish the potential unfavorable impacts of P application methods in the rhizospheric microecological environment.【Methods】A long-term experiment was established in 2011 with sweet potato-wheat rotation system located in Nanjing,Jiangsu Province.In 2020,three treatments were selected for this experiment:no phosphorus fertilizer(NK),chemical fertilizers(NPK),and organic and chemical fertilizers(NPKM).The rhizospheric soils of storage and fibrous roots were collected at the storage root expansion stage of sweet potato.The basic soil chemical properties were determined using standard chemical analytical methods,and the relative abundance,composition and diversity of fungal community were analyzed using Illumina Novaseq High-throughput sequencing technology.【Results】1)Long-term P application altered chemical properties of rhizospheric soils.The organic carbon(SOC),dissolved organic carbon(DOC),available phosphorus(AP),and available potassium(AK)were all significantly increased by P application in both storage and fibrous rhizosphere.The SOC,DOC and AK contents were in order of NPKM>NPK>PK(P<0.05),while AP was in order of NPK>NPKM>NK(P<0.05).Only the AP under NPK was significantly different between the two root types.The pH in fibrous and storage rhizosphere were found to be highest in NPKM,and lowest in NPK treatment.The fibrous rhizosphere pH was 0.81 units higher than that in storage rhizosphere under NPKM treatment.2)The dominant fungi were Ascomycota(70.2%–77.9%),Basidiomycota(5.9%–8.5%),and Mortierellomycota(1.8%–8.1%),regardless of treatments.The relative abundance of Ascomycota in storage rhizosphere was similar among the three treatments,while that in fibrous rhizosphere was significantly(P<0.05)higher in NK treatment than in NPKM treatment.The relative abundance of Basidiomycota and Mortierella was not significant different between NPK and NPKM treatments,nor between the two root types.While the relative abundance of Basidiomycetes and Mortierella in NK treatment decreased by 70.4%and 62.9%compared with NPK treatment,and decreased by 44.0%and 151%compared with NPKM treatment in storage roots.3)The specific quantities of fungal OTUs were 122 and 113 in storage rhizosphere under NPKM and NPK treatments,respectively,while in NK treatment,it was only 86.The specific quantities of fungal OTUs were 160 in fibrous rhizosphere under NPKM treatment,and 114 and 127 in NPK and NK treatments,respectively.The observed species and Shannon diversity index were significantly higher in fibrous rhizosphere under NK treatment than those in storage rhizosphere(P<0.05).The observed species,and Shannon diversity index were highest under NPKM treatment.Topological network analysis showed that the relationships of fungal communities in the rhizosphere of storage roots were more complex,but those in fibrous rhizosphere had stronger interactions.Redundancy analysis indicated that the AP,SOC,and pH in rhizosphere soil were significantly(P<0.05)correlated with fungal community.【Conclusions】Long-term chemical phosphorous fertilization decreased pH,but significantly increased organic carbon and AP in rhizosphere soil.Combined application of chemical and organic fertilizers alleviated the decrease in soil pH,thus maintained higher abundance and diversity of fungi communities in the rhizospheric soils.
作者
王静
袁洁
王磊
张辉
唐忠厚
赵鹏
张爱君
汪吉东
张永春
WANG Jing;YUAN Jie;WANG Lei;ZHANG Hui;TANG Zhong-hou;ZHAO Peng;ZHANG Ai-jun;WANG Ji-dong;ZHANG Yong-chun(Xuzhou Institute of Agricultural Sciences in Xuhuai District of Jiangsu/National Agricultural Experimental Station for Soil Quality,Xuzhou,Jiangsu 221121,China;Institute of Agricultural Resources and Environments,Jiangsu Academy of Agricultural Sciences/Scientific Observing and Experimental Station of Arable Land Conservation(Jiangsu),Ministry of Agriculture and Rural Affairs,Nanjing,Jiangsu 210014,China)
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2023年第5期876-888,共13页
Journal of Plant Nutrition and Fertilizers
基金
国家甘薯产业技术体系项目(CARS-10)
江苏省农业科技自主创新资金项目[CX(21)3002]
徐州市现代农业面上项目(KC21139)
江苏省重点研发项目(BE2021311)。
关键词
甘薯
储藏根
纤维根
根际真菌群落
长期施肥
sweet potato
storage root
fibrous root
rhizospheric fungi community
long-term fertilization
