College of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang 550025, China.
Hainan Key Laboratory of Tropical Eco-Circular Agriculture, Hainan Engineering Research Center for Non-Point Source and Heavy Metal Pollution Control, Institute of Environmental and Plant Protection, Chinese Academy of Tropical Agricultural Sciences, Haikou 570100, China.
Int J Environ Res Public Health. 2022 May 25;19(11):6431. doi: 10.3390/ijerph19116431.
Sandy soils in tropical areas are more vulnerable to potential toxic elements as a result of their low nutrition. The composite addition of biochar and phosphate material is considered a promising method of immobilizing toxic metals in sandy soils, but the synergistic effects of this process still need to be further explored, especially in typical tropical vegetables. In this study, a pot experiment was conducted to evaluate the agronomic and toxic metal-immobilization effects of single amendments (phosphate rock, activated phosphate rock, and biochar) and combined amendments, including biochar mixed with phosphate rock (BCPR) and biochar mixed with activated phosphate rock (BCAPR), on vegetables grown in tropical sandy soil. Among these amendments, the composite amendment BCAPR was the most effective for increasing Ca, Mg, and P uptake based on water spinach ( L.) and pepper ( L.), showing increased ratios of 22.5%, 146.0%, and 136.0%, respectively. The SEM-EDS and FTIR analysis verified that the activation process induced by humic acid resulted in the complexation and chelation of the elements P, Ca, and Mg into bioavailable forms. Furthermore, the retention of available nutrition elements was enhanced due to the strong adsorption capacity of the biochar. In terms of cadmium (Cd) and lead (Pb) passivation, the formation of insoluble mineral precipitates reduced the mobility of these metals within the BCAPR treatments, with the maximum level of extractable Cd (86.6%) and Pb (39.2%) reduction being observed in the tropical sandy soil. These results explore the use of sustainable novel cost-effective and highly efficient bi-functional mineral-based soil amendments for metal passivation and plant protection.
热带地区的沙土由于养分较低，更容易受到潜在有毒元素的影响。生物炭和磷酸盐材料的复合添加被认为是固定沙土中有毒金属的一种很有前途的方法，但这一过程的协同效应仍需要进一步探索，特别是在典型的热带蔬菜中。本研究通过盆栽试验，评估了单一改良剂（磷矿、活性磷矿和生物炭）和组合改良剂（生物炭与磷矿混合（BCPR）和生物炭与活性磷矿混合（BCAPR））对在热带沙土中种植的蔬菜的农艺和有毒金属固定效果。在这些改良剂中，基于空心菜和辣椒，复合改良剂 BCAPR 对增加 Ca、Mg 和 P 的吸收效果最为显著，分别增加了 22.5%、146.0%和 136.0%。SEM-EDS 和 FTIR 分析验证了腐殖酸诱导的活化过程导致 P、Ca 和 Mg 等元素的络合和螯合作用形成了生物可利用的形式。此外，由于生物炭具有很强的吸附能力，可增强对有效营养元素的保留。在钝化镉（Cd）和铅（Pb）方面，不溶性矿物沉淀的形成降低了这些金属在 BCAPR 处理中的迁移性，在热带沙土中可提取 Cd（86.6%）和 Pb（39.2%）的最大减少量。这些结果探索了使用可持续的新型经济高效且高效的双功能基于矿物的土壤改良剂来固定金属和保护植物。
