Effects of microbial inoculum on humic acid content of fermented pig manure

【Objective】In order to explore the feasibility of producing fertilizer with high biological humic acid using animal manure, effects of microbial inoculum on humic acid content of fermented products were studied. 【Method】Three treatments of pig manure added with microbial inoculum were designed(microbial inoculum A:8 strains,concentration1.5-2.0×108CFU/g,appending proportion 0.3%;B:5 strains,0.5-1.5×108CFU/g,0.3%;C:3 strains,≥2.0×108CFU/g,3%).The control had no microbial inoculum. A single factor experiment of natural composting was conducted to determine biological humic acid content in fermented products. 【Result】The results showed that microbial inoculum improved biological humic acid content. Microbial inoculum A had the best effects with biological humic acid content of 15.63% and increase rate of 112.94%. 【Conclusion 】It is feasible to produce fertilizer containing high biological humic acid content using pig manure. Special attention should be paid to fermentation period.