Cadmium (Cd) is readily absorbed by plants and can accumulate to concentrations that exceed food standards. Testing strategies that can mitigate plant uptake of Cd are essential to help manage the risk to food quality. We measured whether applying silicon (Si) fertilizer to a soil contaminated with Cd from phosphate fertilizer could decrease Cd concentrations in spinach (Spinacia olearacea) and onion (Allium cepa). The application of Si (1000 and 2500 kg ha⁻¹) increased spinach dry matter (DM) yield and Si concentrations but had no effect on plant Cd concentrations or uptake. Application of Si had no effect on DM yield or Si concentrations in onions, but there was a 45% decrease in Cd concentrations in the onion bulb. Application of Si had no effect on calcium nitrate-extractable Cd. The decrease in Cd concentrations in onions was likely related to Si restricting the movement of Cd from the root to the harvestable part of the plant. These findings indicate that Si may have some potential as a mitigation tool to decrease plant uptake of Cd. Further investigation is required to evaluate its effectiveness across different soil types and test the response of a wider range of crops under field conditions.

镉很容易被植物吸收，并会积累到超过食品标准的浓度。可以减轻植物对Cd吸收的测试策略对于帮助管理食品质量风险至关重要。我们测量了在磷肥污染的土壤中施用硅肥是否可以降低菠菜（Spinacia olearacea）和洋葱（Allium cepa）中Cd的含量。硅的施用（1000和2500 kg ha ^-1）提高菠菜干物质（DM）的产量和Si含量，但对植物Cd浓度或吸收没有影响。施Si对洋葱的DM产量或Si浓度没有影响，但是洋葱鳞茎中Cd浓度降低了45％。硅的施用对硝酸钙可萃取的镉没有影响。洋葱中Cd浓度的降低可能与Si限制了Cd从根部到植物的可收获部分的移动有关。这些发现表明，Si可能具有减轻植物对Cd吸收的缓解潜力。需要进一步研究以评估其在不同土壤类型上的有效性，并测试田间条件下多种农作物的响应。