Effects of Gleditsia sinensis pod powder, coconut shell biochar and rice husk biochar as additives on bacterial communities and compost quality during vermicomposting of pig manure and wheat straw

Abstract

This study investigated the effectiveness of Gleditsia sinensis pod powder (GSPP), coconut shell biochar (CSB), rice husk biochar (RHB) and their mixtures on vermicomposting of pig manure and wheat straw using Eisenia fetida. The results indicated that the addition of GSPP or/and CSB and RHB could greatly enhance the relative abundance of Bacteroidetes, Actinobacteria, and Firmicutes, as well as the activities of celluloses, protease, and alkaline phosphatase. However, the earthworm biomass was increased in the GSPP and/or CSB addition treatments but decreased in RHB addition treatments compared with the control. Compared with the control, addition of 4%GSPP+8%CSB significantly (P < 0.05) accelerated the degradation of organic matter and increased the concentration of nutrients (total N, P, K), NO3--N in final vermicompost. Germination and growth of tomato seedings were also higher (P < 0.05) in vermicompost produced with the addition of 4%GSPP+8%CSB than in control. Consequently, 4%GSPP+8%CSB addition was suggested as an efficient method to improve the vermicomposting of pig manure and wheat straw.