Effect of Quicklime on Microbial Community in Strong Acidic Soil

Quicklime has been used to improve acidic soils for several decades. The influence of quicklime on the microbial community in strong acidic soil of tobacco plants was investigated. Quicklime at concentrations of 0.75, 2.5, and 4.5 g·kg−1 was mixed with the soil for an incubation experiment. The soil physicochemical properties and enzyme activities of each samples were measured, and microbial diversity of the samples at different periods were determined using high-throughput sequencing. Quicklime had a significant impact on the pH, cation exchange capacity, NO3−–N, NH4+–N, K, and P of the soil. Additionally, quicklime contributed to the increased soil urease and soil β-glucosaminidase activities. According to high-throughput sequencing, the microbial diversity had not significantly increased by the 20th day due to quicklime. Similarly, on the 50th day, the diversity of bacteria significantly increased whereas that of fungi was not affected when the quicklime concentration was 0.75 g·kg−1. Rhodanobacter, Gaiellales, Streptomyces, Terrabacter, and Acidobacteriales were the key bacterial genera and Mortierella, Penicillium, Trichoderma, Aspergillus, Talaromyces, and Fusarium were the fungal genera which were affected on the 50th day. Redundancy analysis indicted that pH was an important environmental factor affecting fungal and bacterial communities. Quicklime concentration of 0.75 g·kg−1 positively affected the microbial community in strongly acidic soils of tobacco plants (pH <5).