LAUSR

ABSTRACT Previously, studies of microbial fertilizer were mainly focused on isolation of the functional strains; the comparison among carriers of the fertilizer was seldom studied. In the current paper, we aimed to evaluate the effect of three carriers of microbial fertilizer in saline-alkaline soil. Two Bacillus strains and three carriers, namely activated carbon, spent mushroom substrate and peat, were used to produce microbial fertilizer. Water infiltration and evaporation, microbial community and alfalfa growth were determined. The results showed that the carrier activated carbon accelerated the water infiltration. The microbial communities of the activated carbon and peat carrier treatments were similar. Conversely, the spent mushroom substrate carrier treatment contained a relatively higher abundance of Bacillus and Ilumatobacter and a relatively lower abundance of Arthrobacter, JG30-KF-CM45 and Actinomycetales when compared to the other two treatments. Furthermore, pot experiments demonstrated that the microbial fertilizer with the activated carbon carrier promoted alfalfa growth better than the other two treatments. Overall, the microbial community analysis indicated that the more abundant Bacillus did not promote plant growth in the saline-alkaline soil; instead, the role of activated carbon in saline-alkaline soil remediation was highlighted. This study provides a methodology for microbial fertilizer application in saline-alkaline soil.