Screening of Plant Growth-promoting Bacteria from Purple Soil and Growth Promoting Effects of Its Complex Microbial Inoculant on Ginger Germchit
（1College of Resources and Environment，Southwest University，Chongqing 400715，China；2Biogas Scientific Research Institute，Ministry of Agriculture，Chengdu 610041，Sichuan，China；3Collaborative Innovation Center of Special Plant Industry，Chongqing College of Arts and Sciences，Chongqing 402160，China；4Research Center of Ginger Resource Utilization Engineering Technology of Chongqing City，Chongqing Tianpei Ginger Research Institute Limited Company，Chongqing 402160，China；5Cash Crops Technical Extension Station of Liangping District，Chongqing 405200，China；6College of Life Science，Chongqing Normal University，Chongqing 400716，China）
Three PGPB（Bacillus amyloliquefaciens GN03，Bacillus pumilus RP01 and Bacillus circulans JK02）isolated from purple soil were mixed as a complex bacterial inoculant. A pot experiment was conducted to examine the effects of the complex inoculant on ginger germchit. The results indicated that the treatment of
complex inoculant mixed with cow-dung（T2）had the best performance. Comparing the treatment of commercial bio-fertilizer（CK2），the treatment mixed with cow-dung remarkably increased the numbers of azotobacter，P-solubilizing and K-solubilizing bacteria by 1 674.1%，8 709.1% and 225.2%，respectively. Soil available P and K of the T2 were significantly enhanced by 87.5% and 23.0%，respectively. The tillering numbers，leaf areas，dry weight of shoot and root were increased by 40.0%，45.9%，28.6% and 25.0% under T2，respectively.Applying appropriate PGPB complex microbial inoculant can efficiently improve the micro-ecological environment and promote the growth of ginger germchit in purple soil.