College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, People's Republic of China.
Key Laboratory of Tropical Agro-Environment, Ministry of Agriculture and Rural Affairs, South China Agricultural University, Guangzhou, 510642, People's Republic of China.
Environ Sci Pollut Res Int. 2024 Feb;31(8):12194-12206. doi: 10.1007/s11356-024-31935-9. Epub 2024 Jan 16.
Biochar and silicon (Si) have been widely considered to play an important role in mitigating cadmium (Cd) toxicity. In this study, wild-type rice (WT, high-Si) and Si-deficient mutant rice (lsi1, low-Si) were used as raw materials to prepare biochar at 500℃; the Si concentrations of high- and low-Si biochar were 15.9% and 5.3%, respectively. The impacts of different application rates (0%, 2%, 4%) of high- and low-Si biochars on soil chemical properties, Si and Cd fractions and availability, Cd absorption, and translocation were investigated. The results showed that both types of biochars increased soil pH, soil available nitrogen, and available phosphorus and potassium; and promoted Si uptake and plant growth of rice. Soil available Si, CaCl-Si, acetic-Si, HO-Si, oxalate-Si, and NaCO-Si were also increased by biochar supply, especially for high-Si biochar treatments. In addition, both types of biochars had no effects on soil total Cd, but reduced soil available Cd by 2-17% in early season 2022, and reduced oxidizable Cd and residual Cd. Biochar application did not influence Cd concentrations in roots, stems, and leaves, but significantly increased Cd uptake and transport from stems and leaves to grains. The results suggested that Si-rich biochar could improve soil nutrients, change soil Si/Cd fractions and availability, promote rice growth but increase the risk of Cd toxicity in grains, indicating the complex of straw biochar in remediating Cd-contaminated paddy soil.
生物炭和硅（Si）被广泛认为在减轻镉（Cd）毒性方面发挥着重要作用。本研究以野生型水稻（WT，高硅）和 Si 缺乏突变体水稻（lsi1，低硅）为原料，在 500℃下制备生物炭；高硅和低硅生物炭的 Si 浓度分别为 15.9%和 5.3%。研究了不同施用量（0%、2%、4%）的高硅和低硅生物炭对土壤化学性质、Si 和 Cd 形态和有效性、Cd 吸收和迁移的影响。结果表明，两种生物炭均能提高土壤 pH 值、土壤有效氮、有效磷和有效钾含量，并促进水稻对 Si 的吸收和生长。土壤有效 Si、CaCl-Si、acetic-Si、HO-Si、oxalate-Si 和 NaCO-Si 也因生物炭的供应而增加，尤其是高硅生物炭处理。此外，两种生物炭对土壤总 Cd 没有影响，但在 2022 年早期降低了土壤有效 Cd 含量 2-17%，并降低了可氧化 Cd 和残留 Cd 的含量。生物炭的应用并没有影响根、茎和叶中的 Cd 浓度，但显著增加了 Cd 从茎和叶向籽粒的吸收和转运。结果表明，富 Si 生物炭可以改善土壤养分，改变土壤 Si/Cd 形态和有效性，促进水稻生长，但增加了籽粒中 Cd 毒性的风险，这表明秸秆生物炭在修复 Cd 污染稻田中的复杂性。
