枯草芽孢杆菌对梨园土壤肥力及梨树根际土壤微生物的影响OA

To clarify the impact of Bacillus subtilis on soil fertility in pear orchards,as well as its role in optimizing soil microbiota,and to explore sustainable fertilization methods that can improve the soil microenvironment,providing scientific basis for scientific fertilization and improving soil microecology.Two treatments were set up in the experiment:T1,adding Bacillus subtilis on the basis of conventional fertilizer management;T2(control),on the basis of conventional fertilizer management,add inactivated Bacillus subtilis.The soil physical and chemical differences and soil microbial diversity were analyzed,and 16S rDNA gene from bacteria and rDNA ITS gene from fungi sequencing were used to analyze the soil microbial diversity and community structure of the pear orchard soil.The results showed that the addition of Bacillus subtilis in conventional fertilization effectively improved soil physical and chemical properties,while also causing changes in the soil microenvironment.From the perspective of soil physicochemical properties,compared with the control,the pH value of fertilizer containing Bacillus subtilis(T1)decreased from 8.14 to 7.93,and the contents of organic matter,available phosphorus,and available potassium were also higher,which were 14.46 g/kg,33.42 mg/kg,and 115.82 mg/kg respectively.From the perspective of microbial diversity,the α diversity index analysis showed that the ACE index,Chao1,and Shannon index of bacteria and fungi in the T1 treatment treated with Bacillus subtilis were lower than those in the control,and the Chao1 index of fungi in the T1 treatment was significantly lower than that in the control.This means that after adding Bacillus subtilis fertilizer,the richness and diversity of bacteria and fungi in the soil have decreased to a certain extent,among which the decrease in the richness and diversity of fungi is more obvious,indicating that the addition of Bacillus subtilis drives the"bacterialization"trend of the soil.From the perspective of the composition of soil bacterial and fungal communities,the T1 treatment increased the relative abundance of beneficial bacteria in soil,such as Proteobacteria,Gemmatimonadota,Bacteroidota and Firmicutes,and reduced the relative abundance of harmful bacteria,such as Acidobacteriota,Myxococcota,Verrucomicrobiota,Basidiomycota and Mucoromycota.NMDS analysis confirmed that Bacillus subtilis had a significant effect on the beta diversity of soil microbial community.This indicates that the microbial fertilizer is one of the main factors driving changes in microbial communities.LEfSe differential analysis showed that in the T1 treatment,the Gammaproteobacteria,Ramlibacter,and Nitrosospira were significantly enriched,while Frankiales,Azospirillales,Sphingomonadaceae,Azospirillaceae,and Sphingomonadales were significantly enriched in the control.In conclusion,on the basis of conventional fertilization,adding Bacillus subtilis can effectively improve the physical and chemical properties of the pear orchard soil,increase the abundance of beneficial microorganisms,drive the development of soil"bacterialization",maintain the microecological health of pear trees,and ensure the sustainable use and improvement of soil.