摘要
[目的]探究减施氮肥对库尔勒香梨成熟期果园土壤细菌群落结构组成及多样性的影响,为减少氮肥施用,改善梨园土壤微生物群落及保障库尔勒香梨产业高质量发展提供理论依据.[方法]对库尔勒香梨植株设置不施肥(N0P0K0)处理、不施氮肥(N0PK)处理、常规施肥(NPK)处理以及分别较常规施肥用氮量减少10％(N1PK)、20％(N2PK)、30％(N3PK)3个氮肥减量梯度处理.采用高通量测序技术,研究香梨园土壤细菌群落结构组成与群落多样性对氮肥减施的响应,并分析香梨园土壤理化性质与土壤细菌群落结构组成的相关性.[结果]与N0PK处理相比,N1PK、N2PK和N3PK处理中土壤碱解氮含量显著增加(P＜0.05,下同).土壤细菌群落以放线菌门(Actinobacteria)、变形菌门(Proteobacteria)和厚壁菌门(Firmicutes)为主要优势菌门,N1PK处理下放线菌门的相对丰度较NPK处理增加13.99％;细菌群落以芽孢杆菌属(Bacillus)、考克氏菌属(Kocuria)、盐单胞菌属(Halomonas)和节杆菌属(Arthrobac-ter)为主要优势菌属,N2PK处理下节杆菌属的相对丰度较NPK处理明显降低87.50％.N1PK处理下Simpson指数显著高于NPK处理,N2PK处理下Chao1指数、Observed_species指数最低,较N0PK处理分别降低43.23％、39.01％.主坐标分析(PCoA)结果显示,第一主坐标(PCoA1)和第二主坐标(PCoA2)共解释不同处理间库尔勒香梨成熟期果园土壤细菌群落总差异的33.6％,速效钾含量与Chao1指数和O bserved_species指数呈极显著负相关(P＜0.01,下同);与Goods_coverage指数呈极显著正相关.[结论]速效钾是库尔勒香梨果园土壤细菌群落多样性的主要影响因子,在完全施氮基础上减量10％对果园土壤细菌的放线菌门相对丰度以及细菌群落的多样性有明显促进作用,实际生产中适宜的氮肥施用量为270 kg/ha.
Abstract
[Objective]The study aimed to explore the effects of nitrogen fertilizer reduction on the composition and diversity of the bacterial community in the soil(0-20 cm soil layer)of Korla fragrant pear orchards at ripening stage,pro-viding theoretical basis for reducing nitrogen fertilizer application,improving the soil microbial community in pear or-chards,and ensuring the high-quality development of Korla fragrant pear industry.[Method]Treatments were set up for Korla fragrant pear plants,including no fertilization(N0P0K0),no nitrogen fertilizer(NoPK),conventional fertilization(NPK)treatments,as well as 3 nitrogen reduction gradients:nitrogen application reduced by 10％(N1PK),20％(N2PK)and 30％(N3PK)compared to conventional fertilization.High-throughput sequencing technology was employed to study the response of soil bacterial community composition and diversity to nitrogen fertilizer reduction in fragrant pear orchards,and to analyze the correlation between soil physicochemical properties and the structure of soil bacterial commu-nity.[Result]Compared to the N0P0K0 treatment,the content of soil alkali hydrolyzable nitrogen in the N1PK,N2PK and N3PK treatments was significantly increased(P＜0.05,the same below).The soil bacterial community was dominated by the phyla Actinobacteria,Proteobacteria and Firmicutes,and the relative abundance of Actinobacteria under the N1PK treatment increased by 13.99％compared to the NPK treatment.The dominant bacterial genera were Bacillus,Kocuria,Halomonas and Arthrobacter,with the relative abundance of Arthrobacter under the N2PK treatment greatly reduced by 87.50％compared to the NPK treatment with complete nitrogen fertilizer application.The Simpson index under the N1PK treatment was significantly higher than that under the NPK treatment.The Chao1 index and Observed_species index were the lowest under the N2PK treatment,which reduced by 43.23％and 39.01％compared to N0PK treatment respec-tively.The results of principal coordinate analysis(PCoA)showed that the first principal coordinate(PCoA1)and the second principal coordinate(PCoA2)together explained 33.6％of the total variation in soil bacterial community in or-chards under different treatments during the ripening stage of Korla fragrant pear.Additionally,the available potassium content was extremely significantly and negatively correlated with the Chao1 index and Observed_species index(P＜0.01,the same below),while it exhibited an extremely significant positive correlation with the Goods_coverage index.[Con-clusion]Available potassium is the primary factor influencing the diversity of soil bacterial community in Korla fragrant pear orchards.Reducing nitrogen application by 10％on the basis of complete nitrogen fertilizer application greatly pro-motes the relative abundance of Actinobacteria and the diversity of bacterial communities in the orchard soil.The appropria-te nitrogen fertilizer application rate is 270 kg/ha in actual production.
维普
万方数据