Effects of Biochar on Cadmium Availability, Nitrification and Microbial Communities in Soils with Varied pH Levels

作者：Wei Zhao, Xiaoxu Cao, Hong Pan, Yanhong Lou, Hui Wang, Quangang Yang, Yuping Zhuge · 发表于：Microorganisms · 年份：2025 · DOI：10.3390/microorganisms13040839 · 被引用次数：9 · 研究领域：Chromium effects and bioremediation、Heavy metals in environment、Wastewater Treatment and Nitrogen Removal

Cadmium (Cd) contamination poses severe threats to agricultural productivity and ecosystem health. Biochar has shown promise in immobilizing Cd and enhancing microbial functions, yet its pH-dependent mechanisms remain underexplored. This study aimed to elucidate pH-dependent variations in biochar-mediated cadmium (Cd) immobilization efficiency, nitrification activity, and bacterial community diversity across soils of contrasting pH levels, with mechanistic insights into the synergistic interplay between biochar properties and soil pH. Real-time quantitative PCR (qPCR) and high-throughput sequencing were used to investigate the effects of a 1% (w/w) biochar amendment on ammonia-oxidizing microorganism abundance and microbial diversity in neutral Shandong soil (SD, pH 7.46) and acidic Yunnan soil (YN, pH 5.88). In neutral SD soil, available Cd decreased from 0.22 mg kg−1 (day 0) to 0.1 mg kg−1 (day 56) and stabilized, accompanied by insignificant changes in ammonia-oxidizing bacteria (AOB) abundance. However, nitrification activity was enhanced through the enrichment of Nitrospira (nitrite-oxidizing bacteria within Nitrospirales and Nitrospiraceae). In acidic YN soil, biochar reduced available Cd by 53.37% over 56 days, concurrent with a 34.28% increase in AOB amoA gene abundance (predominantly Nitrosomonadales), driving pH-dependent nitrification enhancement. These findings demonstrated that biochar efficacy was critically modulated by soil pH; the acidic soils require higher ...