The Effect Of Combined Application Of Microbial Agents On Soil Microbial Properties In Wind-water Crisscross Erosion Region Of Northwest Liaoning

Soil improvement in wind-water erosion crisscrossed region has been paid much attention.Microbial agents can improve soil environment,promote plant survival and growth,and significantly improve soil improvement effect.However,there are few studies on the improvement technology of multi-microbial agents combined application and the driving effect of microbial agents on soil microorganisms.In order to clarify the effects of combined application of fungi on soil microbial properties in wind-water erosion cross area in northwest Liaoning Province,and to explore the soil improvement effects of combined application of fungi,arbuscular mycorrhizal fungi(AMF),Trichoderma harzianum(TH)and Bacillus mucilaginosus(BM)were used as the improvement agents,and single application and mixed application treatments were set.By comparing plant biomass,soil enzyme activity,microbial quantity and soil microbial community structure,the improvement effect of microbial agent combined application technology on soil in this type of area was clarified,and the driving effect of microbial agent on soil microbial properties was revealed,which provided a theoretical basis for soil improvement in wind-water erosion interleaved area.Research indicates:(1)AMF treatment significantly increased the activities of sucrase and dehydrogenase,and AMF.BM treatment had the highest increase in urease,catalase and phosphatase.At the same time,this treatment significantly increased the total biomass of Populus simonii.Soil enzyme comprehensive index(SEI)and the soil enzyme activity recovery index(ERI)consistently showed that AMF.BM treatment had the best effect.It shows that the combination of AMF and BM can effectively improve soil and promote plant growth,and the two bacteria form an efficient synergistic mechanism.(2)All treatments significantly promoted soil respiration,and the single application of BM had the highest improvement compared with CK,followed by the mixed application of AMF.TH.The MBC content of the AMF.BM treatment was significantly higher than that of the other treatments;the MBC/MBN values of all treatments were lower than 5,indicating that the dominant fungi in the soil of all treatments were bacteria,which was basically consistent with the microbial molecular sequencing results in this study.AMF.BM treatment had the lowest metabolic entropy,indicating that the treatment had a good effect on soil environment.(3)The bacterial-specific OTUs of all treatments were less than the common number,among which AMF.BM had the most,accounting for 18.30% of the total;diversity analysis showed that the diversity index of TH treatment was the highest,and the richness index of AMF.BM treatment was the highest.The dominant groups were Firmicutes,Proteobacteria,Acidobacteria,Bacteroidetes and Actinomycetes.Different inoculant treatments changed the relative abundance and functional groups of the dominant bacterial phyla.AMF.BM had significant driving effects on13 of the 25 dominant functional groups.(4)Except that the composition and relative abundance of the fungal community in the BM treatment were lower than those in the CK treatment,all other treatments were significantly improved,and the dominant taxa were Ascomycota,Basidiomycota,Mortierella and Mucor.The fungal community treated with AMF.BM tended to be more diverse,the distribution was more uniform,and the bacterial community structure had a higher stability,indicating that the two bacteria mixed application had a good synergistic effect.AMF.BM significantly drove the functions of four saprophytic trophic communities,and had no significant driving effect on symbiotic trophic functional groups,but showed a negative correlation with pathological trophic functional groups,showing its superiority.In conclusion,AMF.BM treatment significantly increased the total biomass of Populus simonii,SEI and ERI,MBC and microbial diversity,and reduced the metabolic entropy,thus achieving the best improvement effect,which has a certain application prospect in soil improvement in northwest Liaoning province.