College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610068, People's Republic of China.
Key Laboratory of Land Resources Evaluation and Monitoring in Southwest, Ministry of Education of China, Chengdu, 610066, People's Republic of China.
Environ Geochem Health. 2021 Dec;43(12):5087-5098. doi: 10.1007/s10653-021-00949-4. Epub 2021 Apr 28.
The hilly region of western Sichuan is famous for producing Mengding-mountain tea in China. However, it is very easy to enrich fluorine (F) in tea, which recently raised people's concern on fluorosis. In this study, we simulated the local special climate conditions, especially the natural precipitation through column leaching experiment to investigate the effect of fertilization on F desorption from soil. The results suggested different fertilizers could greatly affect desorption of F from soil, but only urea (CO(NH)) could significantly and continuously promote the dissolution of F from soil. Furthermore, to reveal the effect of CO(NH) on migration of F from soil to tea, field plots experiment in a tea garden was carried out. The results showed that CO(NH) promoted soil acidification continuously, resulting in the increase of dissolved F and Al content in soil, which were migrated to tea in the form of F-Al complex. Therefore, the key to reducing the F content in tea is to alleviate soil acidification and reduce F-Al complex content in soil. Most importantly, with CO(NH) addition, the contents of F in tea increased significantly from first bud to fifth bud in comparison with those of without CO(NH), especially in 2016, indicating the accelerating and prolonging enrichment of F in tea by adding CO(NH). This study would have important guidance for controlling F mitigation from soil to tea by managing fertilizers application and anthropogenic activities.
川西丘陵地区以产中国蒙顶山茶而闻名。然而，茶叶中很容易富积氟（F），这引起了人们对氟中毒的关注。本研究通过柱浸实验模拟当地特殊的气候条件，尤其是自然降水，研究施肥对土壤中 F 解吸的影响。结果表明，不同肥料对土壤中 F 的解吸有很大影响，但只有尿素（CO(NH))能显著且持续地促进 F 从土壤中的溶解。此外，为了揭示 CO(NH)对 F 从土壤向茶树迁移的影响，在茶园进行了田间小区实验。结果表明，CO(NH)持续促进土壤酸化，导致土壤中溶解 F 和 Al 含量增加，以 F-Al 络合物的形式迁移到茶树中。因此，降低茶叶中 F 含量的关键是缓解土壤酸化，降低土壤中 F-Al 络合物的含量。更重要的是，与不添加 CO(NH)相比，添加 CO(NH)后，茶树第一芽至第五芽的 F 含量显著增加，尤其是在 2016 年，表明添加 CO(NH)会加速和延长 F 在茶叶中的富集。本研究对通过管理肥料施用和人为活动来控制土壤中 F 向茶叶迁移具有重要指导意义。
