Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environment and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, People's Republic of China.
National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangzhou, 510650, People's Republic of China.
Environ Sci Pollut Res Int. 2022 Nov;29(55):83969-83980. doi: 10.1007/s11356-022-21623-x. Epub 2022 Jul 1.
Biochar is widely used for immobilizing heavy metals in soil as a kind of high-effective passivator. This research conducted incubation and simulated rainfall experiments to study the effects of biochar application on the loss characteristics of runoff and sediment, as well as the transportation of the Cd during the water erosion process. Two rainfall intensities (60 and 120 mm h) and five biochar application rates (0%, 1%, 3%, 5%, and 7%) were considered in the experiment. The result showed that slaking had a greater effect than mechanical stirring in aggregate breakdown of the soil, and the addition of biochar generally increased the sensitivity of the soil to wet stirring, while had no obvious influence on the resistance to slaking. The HO and CaCl extractable Cd in soil significantly decreased with the increase of biochar application rate. The runoff yields decreased with the increase of biochar application rate at both the two rainfall intensities, while the eroded sediment generally decreased at the 120 mm h rainfall intensity. The addition of biochar tended to increase the loss of the middle-sized (1-0.05 mm) aggregates at the 60 mm h rainfall intensity, whereas reduced their loss at the 120 mm h rainfall intensity. Biochar application could significantly reduce the concentration of Cd in the runoff and decreased the total loss amount of Cd (sediment+runoff) in most of the cases. Excessively high level (7%) of biochar application may aggravate soil erosion and result in more Cd loss.
生物炭作为一种高效稳定剂被广泛应用于固定土壤中的重金属。本研究通过培养和模拟降雨实验，研究了生物炭的应用对径流水和泥沙流失特征以及水蚀过程中 Cd 迁移的影响。实验考虑了两种降雨强度（60 和 120mm h）和五种生物炭施用量（0%、1%、3%、5%和 7%）。结果表明，与机械搅拌相比，淋溶对土壤团聚体的破坏作用更大，添加生物炭通常会增加土壤对湿搅拌的敏感性，而对抗淋溶的影响不明显。土壤中 HO 和 CaCl 可提取 Cd 含量随生物炭施用量的增加而显著降低。在两种降雨强度下，随着生物炭施用量的增加，径流量均呈减少趋势，而侵蚀泥沙量一般在 120mm h 降雨强度下减少。添加生物炭往往会增加中等粒径（1-0.05mm）团聚体在 60mm h 降雨强度下的损失，而在 120mm h 降雨强度下则减少其损失。生物炭的施用可显著降低径流水体中 Cd 的浓度，并在大多数情况下减少 Cd（泥沙+径流）的总流失量。过高水平（7%）的生物炭施用量可能会加剧土壤侵蚀，导致更多 Cd 的流失。
