School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China; Key Laboratory of Effective Utilization of Agricultural Water Resources of Ministry of Agriculture, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China; Heilongjiang Provincial Key Laboratory of Water Resources and Water Conservancy Engineering in Cold Region, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China.
School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China; Key Laboratory of Effective Utilization of Agricultural Water Resources of Ministry of Agriculture, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China; Heilongjiang Provincial Key Laboratory of Water Resources and Water Conservancy Engineering in Cold Region, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China.
Environ Pollut. 2022 Nov 15;313:120143. doi: 10.1016/j.envpol.2022.120143. Epub 2022 Sep 9.
The problem of potentially toxic elements (PTEs) in farmland is a key issue in global pollution prevention and control and has an important impact on environmental safety, human health, and sustainable agricultural development. Based on the climate background of high-latitude cold regions, this study simulated freeze-thaw cycles through indoor tests. Different initial conditions, such as biochar application rates (0%, 1%, 2%) and different initial soil moisture contents (15%, 20%, 25%), were set to explore the morphological changes in cadmium (Cd) and lead (Pb) in soil and the response relationship to the changes in soil physicochemical properties. The results indicate that soil pH decreases during freeze-thaw cycles, and soil alkalinity increases with increasing biochar content. Freeze-thaw cycles caused the total amount of PTEs to have a U-shaped distribution, and the amount of PTEs in the soluble (SOL) and reducible (RED) fraction increased by 0.28-56.19%. Biochar reduced the amount of Cd and Pb migration in the soil, and an increase in soil moisture content reduced the availability of Cd and Pb in the soil. Freezing and thawing damaged the soil structure, and biochar reduced the fractionation of small particle aggregates by enhancing the stability of soil aggregates, thereby reducing the soil's ability to adsorb Cd and Pb. In summary, for farmland soil remediation and pollution control, the application of biochar has a certain ability to optimize soil properties. Considering the distribution of PTEs in the soil and the physicochemical properties of the soil, the application of 1% biochar to soil with a 20% moisture content is optimal for regulating seasonally frozen soil remediation.
农田中潜在有毒元素（PTEs）的问题是全球污染防控的关键问题，对环境安全、人类健康和可持续农业发展有着重要影响。本研究基于高纬寒区气候背景，通过室内试验模拟冻融循环。设置不同的初始条件，如生物炭施用量（0%、1%、2%）和不同的初始土壤含水量（15%、20%、25%），来探究土壤中镉（Cd）和铅（Pb）的形态变化及其对土壤理化性质变化的响应关系。结果表明，冻融循环过程中土壤 pH 值降低，土壤碱性随生物炭含量增加而增加。冻融循环导致 PTEs 总量呈 U 型分布，可溶态（SOL）和可还原态（RED）中 PTEs 总量增加了 0.28-56.19%。生物炭减少了土壤中 Cd 和 Pb 的迁移量，增加土壤含水量降低了土壤中 Cd 和 Pb 的有效性。冻融破坏了土壤结构，生物炭通过增强土壤团聚体的稳定性减少了小颗粒团聚体的分馏，从而降低了土壤对 Cd 和 Pb 的吸附能力。综上所述，对于农田土壤修复和污染控制，生物炭的应用具有一定的优化土壤性质的能力。考虑到土壤中 PTEs 的分布和土壤的理化性质，将 1%的生物炭应用于含水量为 20%的土壤中，对于调节季节性冻土的修复效果最佳。
