微粒聚谷氨酸配施化肥对棉花生长和土壤养分及微生物群落结构的影响

Effects of Particulate Polyglutamic Acid Combined with Chemical Fertilizer on Cotton Growth,Soil Nutrients,and Microbial Community Structure

利用棉花盆栽试验,设置5个处理(P1(4.5 g微粒聚谷氨酸(γ-PGA)配施1 g化肥)、P2(3 g微粒γ-PGA配施1 g化肥)、P3(1.5 g微粒γ-PGA配施1 g化肥)、N(1 g化肥)和CK(不施肥)),通过分析棉花的农艺性状,并结合高通量测序技术,探究施用微粒γ-PGA配施化肥对棉花植株生长和土壤微生物群落结构的影响,以确定合理的配施剂量。结果表明,微粒γ-PGA配施化肥的棉花农艺性状优于单施化肥和不施肥,1.5 g微粒γ-PGA配施化肥效果最佳。在棉花生育期微粒γ-PGA配施化肥的土壤中全钾、铵态氮和有效磷的含量高于单施化肥和不施肥,在采后土壤中全钾、铵态氮、有效磷和有效钾含量保持较高水平。高通量测序结果表明,微粒γ-PGA配施化肥会引起微生物的丰富度和多样性的降低,但可以改善微生物群落结构,在采摘之后,土壤中的变形菌门、子囊菌门和被孢霉门的相对丰度都呈降低态势,而放线菌门、酸杆菌门和担子菌门的相对丰度则呈上升态势,与单施化肥和不施肥相比,大部分菌门依旧保持高的相对丰度。冗余(RDA)分析可知,土壤微生物优势菌门受包括全磷、全钾、有效磷、有效钾、酸碱度、有机质含量等多个关键因子的影响,随着时间的变化,微生物优势菌门受这些关键因子的影响也可能会有差异。微粒γ-PGA配施化肥可促进棉花的生长发育,虽会降低细菌和真菌群落的整体丰富度与多样性,但使微生物群落种类相对集中在部分有益菌群上,且在棉花采摘后依旧能维持较高的相对丰度,可改善土壤质量,维持较高的土壤生物活性,有利于农业生产。

The aim of this study was to investigate the effects of microparticle polyglutamic acid(γ-PGA)on cotton plant growth and rhizosphere soil microorganisms,and to determine the reasonable combined application dose.In this study,using a pot experiment of cotton,five treatments(P1(4.5 g of particulateγ-PGA combined with 1 g of chemical fertilizer),P2(3 g of particulateγ-PGA combined with 1 g of chemical fertilizer),P3(1.5 g of particulateγ-PGA combined with 1 g of chemical fertilizer),N(1 g of chemical fertilizer),and CK(no fertilization))were set,the effects of particulate polyglutamic acid(γ-PGA)on growth of cotton plants and soil microbial community structure by analyzing cotton agronomic traits and high-throughput sequencing technology.The results showed that the agronomic traits of cotton in the treatments of particulateγ-PGA combined with chemical fertilizer were superior to those in the treatments of chemical fertilizer alone or no fertilizer,and 1.5 g of particulateγ-PGA combined with chemical fertilizer had the best effect.The contents of total potassium,ammonium nitrogen,and available phosphorus in the soil under particulateγ-PGA combined with chemical fertilizer were higher than those in the soil under chemical fertilizer alone or no fertilizer during the growth period of cotton.The contents of soil total potassium,ammonium nitrogen,available phosphorus,and available potassium remained high after harvest.High-throughput sequencing results showed that particulateγ-PGA combined with chemical fertilizer caused a reduction in microbial richness and diversity,but improved the microbial community structure.The relative abundance of Proteobacteria,Ascomycota and Mortierellomycota showed a downward trend after harvest,while the relative abundance of Actinobacteria,Acidobacteria and Basidiomycota showed an upward trend.Compared with chemical fertilizer alone and the control of water,most of the bacterial phyla still maintained high relative abundance.According to the redundancy analysis(RDA),the dominant phyla of soil microorganisms were affected by multiple key factors,including total phosphorus,total potassium,available phosphorus,available potassium,pH,and organic matter content.The effects of these key factors on the dominant phyla of soil microorganisms may vary with time.Particulateγ-PGA combined with chemical fertilizer could promote the growth and development of cotton.Although it reduced the overall richness and diversity of bacterial and fungal communities,the species of microbial communities were relatively concentrated in some beneficial bacteria which could still maintain a high relative abundance after cotton harvest,improve soil quality,and maintain high soil biological activity,which was conducive to agricultural production.