Effects of nitrogen input on soil bacterial community in Korla fragrant pear orchard
[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/hm2 on the soil bacterial community were studied by analyzing the relative abundance and α diversity 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/hm2 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.
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