Atmospheric deposition plays a significant role in introducing cadmium (Cd) into agroecological systems; however, accurately determining its accumulation in crops through foliar and root uptake presents challenges. This study investigated the bioaccumulation of atmospherically deposited Cd in soybean using a three-year fully factorial atmospheric exposure experiment incorporating Cd isotope analysis. Results shown that atmospheric deposition accounted for 1–13% of soil Cd pools, yet contributed 11–72% of Cd to soybean tissues during the growing seasons. Over the course of soil exposure to atmospheric deposition ranging from 1 to 3 years, no notable variations were observed in Cd concentrations in soil solutions and soybean tissues, nor in isotope ratios. Newly deposited Cd was a major source in soybean plants, and the bioavailability of deposited Cd rapidly aged in soils. Atmospheric Cd enriched in lighter isotopes induced negative isotope shifts in soybean plants. By employing an optimized isotope mixing model in conjunction with a mass balance approach, foliar Cd uptake contributed 13–51%, 16–45%, and 21–56% to stem, leaf, and seed, respectively. This study highlights substantial contribution of foliar uptake of atmospheric deposition to Cd levels in soybean and controlling foliar uptake as a potential strategy in agroecological systems experiencing high atmospheric Cd deposition.

中文翻译：

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常压沉积镉在大豆中的生物积累：结合镉同位素的三年田间试验


大气沉积在将镉 （Cd） 引入农业生态系统方面起着重要作用;然而，通过叶面和根系吸收准确确定其在作物中的积累是一项挑战。本研究使用结合 Cd 同位素分析的为期三年的全因子大气暴露实验调查了大豆中大气沉积 Cd 的生物积累。结果表明，大气沉积占土壤 Cd 库的 1-13%，但在生长季节为大豆组织贡献了 11-72% 的 Cd。在土壤暴露于大气沉积 1 至 3 年的过程中，未观察到土壤溶液和大豆组织中 Cd 浓度的显着变化，同位素比值也没有观察到显着变化。新沉积的 Cd 是大豆植物的主要来源，沉积的 Cd 的生物利用度在土壤中迅速老化。大气中富含较轻同位素的 Cd 诱导大豆植株的负同位素偏移。通过采用优化的同位素混合模型和质量平衡方法，叶面对 Cd 的吸收分别对茎、叶和种子贡献了 13-51%、16-45% 和 21-56%。本研究强调了叶面吸收大气沉积对大豆 Cd 水平的巨大贡献，并控制叶面吸收作为经历高大气 Cd 沉积的农业生态系统的潜在策略。