School of Resources, Environment and Materials, Guangxi University, Nanning, 530004, PR China.
School of Resources, Environment and Materials, Guangxi University, Nanning, 530004, PR China.
J Environ Manage. 2024 Nov;370:122964. doi: 10.1016/j.jenvman.2024.122964. Epub 2024 Oct 28.
How changes in soil properties and heavy metal toxicity induced during biochar remediation of cadmium (Cd) contaminated soils induce changes in microbial communities, and further, how this process affects the soil carbon sequestration capacity by microorganisms, has not been explored. We prepared virgin biochar (named BC400 and BC600) using rice straw at 400 °C and 600 °C and modified biochar (named MNT-BC400 and MNT-BC600) using co-pyrolysis of montmorillonite and rice straw at the same two temperatures, in an attempt to create different CO emission backgrounds during the remediation of cadmium contamination in soil, and to explore the mechanism of soil carbon sequestration capacity during remediation. The results showed that MNT-BC600 was effective in reducing the soil available Cd during incubation without increasing soil carbon emission, whereas soil carbon emission was elevated by 83.10%, 50.19%, and 21.53% in BC400, MNT-BC400, and MNT-BC600 treatments compared to the control group (CK). Microbial carbon use efficiency (CUE) was increased by 20.68%, 18.78%, and 12.73% in BC400, BC600, and MNT-BC600 treatments, respectively. We found that the bacterial module (Bmod#2), dominated by the eutrophic bacteria Proteobacteria and Actinobacteriota, controlled the increase of soil carbon emissions; the bacterial module (Bmod#3) composed of both oligotrophic and eutrophic flora were closely related to soil CUE after remediation; the bacterial module (Bmod#4) consisting of oligotrophic and eutrophic bacteria alone was easily replaced by eutrophic bacteria module (Bmod#2) under eutrophic conditions and had a negative linear relationship with soil CO emission, while the switch in Cd form was more likely to affect the community structure of modules containing eutrophic bacteria. These findings provide new insights into the use of biochar for soil remediation and balancing soil carbon sequestration.
生物炭修复镉污染土壤过程中土壤性质和重金属毒性的变化如何诱导微生物群落的变化，以及进一步地，这一过程如何影响微生物的土壤碳固存能力，这些问题尚未得到探索。我们使用稻秸在 400°C 和 600°C 下制备了原始生物炭（分别命名为 BC400 和 BC600），并使用蒙脱石和稻秸的共热解制备了改性生物炭（分别命名为 MNT-BC400 和 MNT-BC600），试图在修复土壤镉污染过程中创造不同的 CO 排放背景，并探索修复过程中土壤碳固存能力的机制。结果表明，MNT-BC600 在孵育过程中有效降低了土壤有效态 Cd，而没有增加土壤碳排放，而在 BC400、MNT-BC400 和 MNT-BC600 处理中，土壤碳排放分别比对照组（CK）升高了 83.10%、50.19%和 21.53%。微生物碳利用效率（CUE）在 BC400、BC600 和 MNT-BC600 处理中分别增加了 20.68%、18.78%和 12.73%。我们发现，细菌模块（Bmod#2），主要由富营养细菌变形菌门和放线菌门控制，增加了土壤碳排放；修复后，由贫营养和富营养菌群组成的细菌模块（Bmod#3）与土壤 CUE 密切相关；单独由贫营养和富营养细菌组成的细菌模块（Bmod#4）在富营养条件下容易被富营养细菌模块（Bmod#2）取代，与土壤 CO 排放呈负线性关系，而 Cd 形态的变化更可能影响含有富营养细菌的模块的群落结构。这些发现为生物炭在土壤修复和平衡土壤碳固存方面的应用提供了新的见解。
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