Effects of Biochar on Cadmium Availability, Nitrification and Microbial Communities in Soils with Varied pH Levels
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-me...
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2025-04-01
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| author | Wei Zhao Xiaoxu Cao Hong Pan Yanhong Lou Hui Wang Quangang Yang Yuping Zhuge |
| author_facet | Wei Zhao Xiaoxu Cao Hong Pan Yanhong Lou Hui Wang Quangang Yang Yuping Zhuge |
| author_sort | Wei Zhao |
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| description | 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% (<i>w/w</i>) 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<sup>−1</sup> (day 0) to 0.1 mg kg<sup>−1</sup> (day 56) and stabilized, accompanied by insignificant changes in ammonia-oxidizing bacteria (AOB) abundance. However, nitrification activity was enhanced through the enrichment of <i>Nitrospira</i> (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 <i>amoA</i> gene abundance (predominantly <i>Nitrosomonadales</i>), driving pH-dependent nitrification enhancement. These findings demonstrated that biochar efficacy was critically modulated by soil pH; the acidic soils require higher biochar dosages (>1% <i>w/w</i>, adjusted to local soil properties and agronomic conditions) for optimal Cd immobilization. Meanwhile, pH-specific nitrifier taxa (<i>Nitrosomonadales</i> in acidic vs. <i>Nitrospira</i> in neutral soils) underpinned biochar-induced nitrification dynamics. The study provided a mechanistic framework for tailoring biochar remediation strategies to soil pH gradients, emphasizing the synergistic regulation of Cd immobilization and microbial nitrogen cycling. |
| format | Article |
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| institution | OA Journals |
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| language | English |
| publishDate | 2025-04-01 |
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| spelling | doaj-art-be552e5bc3224ecbaff7eb9b863504cc2025-08-20T02:28:24ZengMDPI AGMicroorganisms2076-26072025-04-0113483910.3390/microorganisms13040839Effects of Biochar on Cadmium Availability, Nitrification and Microbial Communities in Soils with Varied pH LevelsWei Zhao0Xiaoxu Cao1Hong Pan2Yanhong Lou3Hui Wang4Quangang Yang5Yuping Zhuge6National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Tai’an 271018, ChinaNational Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Tai’an 271018, ChinaNational Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Tai’an 271018, ChinaNational Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Tai’an 271018, ChinaNational Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Tai’an 271018, ChinaNational Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Tai’an 271018, ChinaNational Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Tai’an 271018, ChinaCadmium (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% (<i>w/w</i>) 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<sup>−1</sup> (day 0) to 0.1 mg kg<sup>−1</sup> (day 56) and stabilized, accompanied by insignificant changes in ammonia-oxidizing bacteria (AOB) abundance. However, nitrification activity was enhanced through the enrichment of <i>Nitrospira</i> (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 <i>amoA</i> gene abundance (predominantly <i>Nitrosomonadales</i>), driving pH-dependent nitrification enhancement. These findings demonstrated that biochar efficacy was critically modulated by soil pH; the acidic soils require higher biochar dosages (>1% <i>w/w</i>, adjusted to local soil properties and agronomic conditions) for optimal Cd immobilization. Meanwhile, pH-specific nitrifier taxa (<i>Nitrosomonadales</i> in acidic vs. <i>Nitrospira</i> in neutral soils) underpinned biochar-induced nitrification dynamics. The study provided a mechanistic framework for tailoring biochar remediation strategies to soil pH gradients, emphasizing the synergistic regulation of Cd immobilization and microbial nitrogen cycling.https://www.mdpi.com/2076-2607/13/4/839cadmium (Cd) contaminationsoil pHbiocharammonia-oxidizing microorganismsnitrificationsoil remediation |
| spellingShingle | Wei Zhao Xiaoxu Cao Hong Pan Yanhong Lou Hui Wang Quangang Yang Yuping Zhuge Effects of Biochar on Cadmium Availability, Nitrification and Microbial Communities in Soils with Varied pH Levels Microorganisms cadmium (Cd) contamination soil pH biochar ammonia-oxidizing microorganisms nitrification soil remediation |
| title | Effects of Biochar on Cadmium Availability, Nitrification and Microbial Communities in Soils with Varied pH Levels |
| title_full | Effects of Biochar on Cadmium Availability, Nitrification and Microbial Communities in Soils with Varied pH Levels |
| title_fullStr | Effects of Biochar on Cadmium Availability, Nitrification and Microbial Communities in Soils with Varied pH Levels |
| title_full_unstemmed | Effects of Biochar on Cadmium Availability, Nitrification and Microbial Communities in Soils with Varied pH Levels |
| title_short | Effects of Biochar on Cadmium Availability, Nitrification and Microbial Communities in Soils with Varied pH Levels |
| title_sort | effects of biochar on cadmium availability nitrification and microbial communities in soils with varied ph levels |
| topic | cadmium (Cd) contamination soil pH biochar ammonia-oxidizing microorganisms nitrification soil remediation |
| url | https://www.mdpi.com/2076-2607/13/4/839 |
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