Immobilization of cadmium and improvement of bacterial community in contaminated soil following a continuous amendment with lime mixed with fertilizers: A four-season field experiment

• Published in: Ecotoxicology and environmental safety 2019-04, Vol.171, p.425-434
• Main Authors: Shi, Lei, Guo, Zhaohui, Peng, Chi, Xiao, Xiyuan, Feng, Wenli, Huang, Bo, Ran, Hongzhen
• Format: Article
• Language: English
• Subjects: Cadmium; Contaminated paddy soil; High-throughput sequencing; Lime-based amendment; Soil bacterial community
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2019.01.006

The effects of the continuous amendments with lime (L), lime mixed with organic manure (LO), or phosphate fertilizer (LP) on the soil bacterial community, soil available cadmium (Cd) content, and Cd accumulation in rice planted in a Cd contaminated paddy soil were determined through a four-season field experiment. The results showed that with continuous application of amendments during the four seasons, the soil pH increased significantly compared with the control, while the soil available Cd content significantly decreased by 12.9–18.2%, 13.1–17.3% and 0.09–23.2% under the L, LO, or LP treatments, and the Cd content of rice was significantly reduced by 28.5–56.2%, 37.6–53.4%, and 31.2–44.6%, respectively. The rice Cd content in each season at amendment treatments was lower than the National Food Safety Standard of China (maximum level of Cd in grains is 0.2 mg/kg). The diversity and richness of soil bacteria significantly increased after the continuous amendments in soil for four-season cropping. Soil pH and available Cd content were important factors for soil bacterial community. Lime mixed with phosphate fertilizer or organic manure had been characterized by a significant increase of Proteobacteria, Nitrospirae, and Chloroflexi and a decrease of Acidobacteria based on an Illumina Miseq sequencing analysis. The results indicate that the continuous application of lime mixed with organic manure or phosphate fertilizer is a very important measure to ensure the quality safety of rice and improve soil quality in a Cd-contaminated paddy. •Lime mixed with organic manure reduced soil Cd availability and Cd translocation in rice.•Lime mixed with fertilizers reduced Cd content in grains without rice yield.•Lime mixed with fertilizers greatly improved the safety of rice and soil quality.•Soil pH and available Cd content are important factors for soil bacterial community.