覆膜处理对藠头根际土壤细菌群落的影响

Effects of plastic film mulching on the rhizosphere soil bacterial community of Allium chinense

为探究覆膜措施对津市藠头产量及根际土壤细菌群落多样性、结构、生态功能、物种之间网络互作的影响,本研究采集了未覆膜、覆普通地膜、覆蓝色地膜3个处理下的藠头根际土壤,利用高通量测序技术和生物信息学的相关方法进行研究。结果表明:覆膜措施提高了藠头产量,其中未覆膜处理产量为29 766.7 kg·hm^(-2),普通地膜处理产量为31 466.7 kg·hm^(-2),增产5.7%,蓝色地膜处理产量为39 966.7 kg·hm^(-2),增产34.3%。覆膜处理显著改变了细菌群落结构,并显著降低了细菌群落多样性。此外,藠头根际土壤细菌群落对不同地膜处理的响应不同,在门和属水平上均存在一定差异。网络分析结果表明,未覆膜处理具有124个模块,普通地膜和蓝色地膜处理的根际细菌分子生态网络分别具有77个和80个模块。覆膜措施使藠头根际细菌分子生态网络的模块数降低,这可能会导致细菌群落生态功能多样性降低。覆膜措施还导致根际细菌关键物种改变。基于功能预测,相较于未覆膜处理,覆盖蓝色地膜显著提高了尿素分解功能(P<0.05),而普通地膜处理相对于蓝色地膜处理能显著提升好氧氨氧化与硝化作用(P<0.05)。研究表明,蓝色地膜处理更有利于藠头的增产,覆膜措施改变了藠头根际细菌群落结构、关键物种及物种互作关系。此外,尚不能忽视覆膜措施对农田土壤细菌生态环境的潜在风险。

In order to explore the influence of plastic mulch treatment on the yield,community diversity,structural composition,bacterial species interactions,and microecological function of rhizosphere bacteria,an experiment was conducted at an Allium chinense field in Jinshi City,Hunan Province.The rhizosphere soils of Allium chinense under different plastic mulch treatments(control group,normal plastic mulch treatment,and blue plastic mulch treatment)were collected;16S high-throughput sequencing and bioinformatics approach were then used to extract bacteria from the corresponding soil samples.The results showed that plastic mulch film treatment promoted the production of Allium chinense,with the corresponding rhizosphere exhibiting that bacterial structure had been reshaped and a lower bacterial diversity than those of the control soil.The yield of the control group was 29766.7 kg·hm^(-2);the yield of the normal mulch treatment was 31466.7 kg·hm^(-2),exhibiting an 5.7%yield increase;and the yield of the blue plastic mulch treatment was 39966.7 kg·hm^(-2),exhibiting a corresponding yield increase of 34.3%.The bacterial community composition of the Allium chinense rhizosphere soil possessed differences at the phylum and genus levels.Network analysis showed that the control,normal plastic film mulch,and blue plastic film mulch groups had 124,77,and 80 modules,respectively.The results of this network analysis indicated that the network within plastic film mulched soil contained fewer functionally interrelated microbial modules than the control soil,which may lead to a corresponding decrease in the ecological functions of the bacterial community.Plastic film mulching reduced the number of overall keystone species.In addition,blue plastic film mulching significantly increased the function of ureolysis;further,normal transparent plastic film mulching significantly increased the function of aerobic ammonia oxidation and nitrification compared with those of the other groups(P<0.05).This study demonstrated that blue plastic mulch film treatment is more beneficial to yield promotion and plastic mulch film treatment significantly altered the core species,bacterial community structure,and bacterial interactions within the rhizosphere soil of Allium chinense.Nonetheless,the potential risk of plastic mulch film treatment to the ecological environment of the bacteria within the soil should not be ignored.