Effects of microbial fertilizer on broccoli growth and soil microbial characteristics

The effects of a microbial fertilizer on broccoli (Brassica oleracea) biological indicators and soil microbial biomass were tested in field experiments under different treatments (control, microbial fertilizer, 70% chemical fertilizer + microbial fertilizer, 100% chemical fertilizer). Biological indicators and soil microbial biomass increased in all fertilizer treatments compared to the control. The numbers of soil bacteria, fungi, and actinomycetes decreased with soil depth with fertilizer treatments. The numbers of microbes showed a tendency of bacteria actinomycetes fungi with fertilizer treatments. The effects of the 70% chemical fertilizer + microbial fertilizer were the greatest among fertilizer treatments. Plant height, stem diameter, number of leaves, aboveground fresh weight, aboveground dry weight, underground fresh weight, underground fresh dry weight, bacteria population, actinomycete population, total microbial population, soil microbial biomass carbon, soil microbial biomass nitrogen, and soil microbial biomass phosphorus increased by 6.82%, 11.53%, 11.76%, 9.68%, 33.33%, 62.5%, 33.33%, 34.04%~37.61%, 8.42%~15.87%, 32.53%~3.86%, 13.56%~18.6%, 3.99% and 12.81%~17.99%, respectively. The numbers of fungi decreased 26.23%~32.89%. Correlation analysis showed that there were significant positive correlations among soil microbial biomass and the number of soil microorganisms. 70% chemical fertilizer + microbial fertilizer promoted broccoli growth.