氮输入对库尔勒香梨园土壤细菌群落的影响

Effects of nitrogen input on soil bacterial community in Korla fragrant pear orchard

【目的】为梨园的合理施肥及可持续健康发展提供参考。【方法】以库尔勒香梨园0~20 cm土层土壤样品为材料,通过分析细菌群落物种组成的相对丰度、α多样性指数,研究了0、150、300、450 kg/hm^(2)共4个施氮水平对库尔勒香梨园土壤细菌群落的影响。【结果】电导率、碳氮比、全氮含量及硝态氮含量对门水平细菌群落的影响达显著水平,硝态氮含量、铵态氮含量、碱解氮含量、全碳含量、碳氮比及电导率对属水平细菌群落的影响达显著水平。施用氮肥后,放线菌门Actinobacteria、类诺卡氏属Nocardioides的相对丰度有所下降,且与土壤氮养分含量以及pH值显著或极显著负相关;施用氮肥后,厚壁菌门Firmicutes、异常球菌-栖热菌门Deinococcus-Thermus、己科河菌门Rokubacteria、A4b、动孢菌属Kineosporia的相对丰度有所增加,芽孢杆菌属Bacillus、盐单胞菌属Halomonas在膨果期的相对丰度在施用氮肥后有所增加,其中己科河菌门的相对丰度与土壤碳氮养分含量以及pH值有显著或极显著相关性,A4b的相对丰度与有机碳含量显著或极显著正相关,动孢菌属的相对丰度与土壤氮养分含量以及pH值显著或极显著正相关,芽孢杆菌属的相对丰度与全氮含量、铵态氮含量显著正相关;绿弯菌门Chloroflexi以及在膨果期的酸杆菌门Acidobacteria、考克氏菌属Kocuria、游球菌属Planococcus的相对丰度随施氮量的增加呈先增加、后降低的趋势,绿弯菌门、酸杆菌门的相对丰度与有机碳含量显著或极显著正相关。在膨果期,随施氮量的增加,细菌群落的Pielou均匀度指数、Shannon指数均表现为先增加、后降低的趋势,300 kg/hm^(2)处理下最高;各处理Chao1指数和Observed species指数均表现为在成熟期最高。相关性分析结果表明细菌群落多样性主要受氮组分含量、有机碳含量以及pH值的影响。【结论】添加氮肥可以影响土壤细菌群落的组成及其多样性,因此适当控制氮素的供给以及调节土壤碳氮比、pH值等,可改善土壤微生物群落结构,维持土壤品质的稳定和微生物区系的健康。

【Objective】To provide reference for rational fertilization and sustainable and healthy development of pear orchard.【Method】Using 0-20 cm soil layer of Korla pear garden as material,the effects of nitrogen application levels of 0,150,300,450 kg/hm^(2)on the soil bacterial community were studied by analyzing the relative abundance andαdiversity index of bacterial community composition.【Result】The effects of electrical conductivity,carbon to nitrogen ratio,total nitrogen content and nitrate nitrogen content on phylum level bacterial community were significant,and the effects of nitrate nitrogen content,ammonium nitrogen content,alkali-hydrolyzed nitrogen content,total carbon content,carbon to nitrogen ratio and electrical conductivity on genus level bacterial community were significant.After application of nitrogen fertilizer,the relative abundance of Actinobacteria and Nocardioides decreased,and was significantly or extremely significantly negatively correlated with soil nitrogen content and pH value.The relative abundance of Firmicutes,Deinococcus-Thermus,Rokubacteria,A4b and Kineosporia increased after nitrogen fertilizer application.The relative abundance of Bacillus and Halomonas increased after application of nitrogen fertilizer.The relative abundance of Hexaceae was significantly correlated with soil carbon and nitrogen nutrient content and pH value,and the relative abundance of A4b was significantly or positively correlated with organic carbon content.The relative abundance of Actinospora was significantly positively correlated with soil nitrogen nutrient content and pH value,and the relative abundance of Bacillus was significantly positively correlated with total nitrogen content and ammonium nitrogen content.The relative abundance of Chloroflexi and Acidobacteria,Kocuria and Planococcus at the rising stage increased first and then decreased with the increase of nitrogen application.The relative abundance of chlorocurvula and Acidobacteria was significantly or extremely significantly positively correlated with the content of organic carbon.At the rising stage,Pielou evenness index and Shannon index of bacterial community increased first and then decreased with the increase of nitrogen application rate,and the highest value was found under 300 kg/hm^(2)treatment.Each processing Chao1 index and Observed The index of species was the highest at the maturity stage.The results of correlation analysis showed that the diversity of bacterial community was mainly affected by nitrogen content,organic carbon content and pH value.【Conclusion】The addition of nitrogen fertilizer can affect the composition and diversity of soil bacterial community.Therefore,proper control of nitrogen supply and adjustment of soil carbon to nitrogen ratio and pH value can improve the structure of soil microbial community,maintain the stability of soil quality and the health of microflora.