Effects of different organic fertilisers on the microbial functional diversity and bacterial communities in a tobacco soil

A long-term field experiment was conducted to investigate the effects of organic manure (commercial organic manure, CFM1; cow manure, CFM2; green manure, CFM3) and chemical fertiliser (CK) on the microbial diversity of a tobacco-planted soil using Biolog ECO and 16S rRNA sequencing technology. The results showed that organic manure treatments increased the available nutrient content in the soil, including nitrogen (AN, 2.1–13.3%), potassium (AK, 14.2–31.8%), labile organic carbon (19.9–37.4%), and microbial biomass carbon (11.9–21.0%), as well as the mean weight diameter and geometric mean diameter. The average well colour development value and McIntosh diversity index in CFM1 treatment increased by 23.6% and 18.9%, respectively, compared with CK. The 16S rRNA sequencing analysis suggested that CFM1 and CFM2 treatments improved the richness and diversity of soil bacteria and recruited more potentially beneficial bacteria. Redundancy analysis showed that soil physicochemical properties, excluding AN and Olsen–P were positively correlated with the abundance of bacteria dominant in the CFM1 treatment. This indicates that application of CFM1 is a sound fertilisation strategy to improve soil fertility and create a good ecological environment.