The effectiveness and longevity of amendments will influence the reduction in cadmium (Cd) bioavailability by in situ remediation techniques. Different amendments, including red mud (RM), corn straw (CS), rape straw (RS), and their combinations with zinc (Zn) fertilizer, were evaluated based on a long-term field experiment. It was found that all amendments decreased the concentration of available-Cd (EDTA-Cd and Exch-Cd) in soil and also reduced the Cd content (%) in plants. The amendments were still effective after eight years, although the effect did decline over time. The reduction of plant Cd content was 83.5% for red mud plus rape straw (RMRS), 65.3% for red mud plus corn straw (RMCS), 50.9% for RS, 54.0% for RM, and 37.3% for CS in the first few years. The reduction in plant Cd content was still 17.2% for RMRS after eight years, and RMRS was found to be the most effective treatment for decreasing Cd bioavailability. This study also explained that why the reduction in plant Cd content declined over time is the change of available Cd content in soil over time, which is important for guiding agricultural practice. It was concluded that RM, CS, RS, and their combinations with Zn fertilizer as effective amendments can have a profound and lasting positive impact on Cd-contaminated soils.

修订的有效性和寿命将影响原位降低镉（Cd）生物利用度修复技术。在长期的田间试验的基础上，评估了不同的改良剂，包括赤泥（RM），玉米秸秆（CS），油菜秸秆（RS）以及它们与锌（Zn）肥料的组合。发现所有的改良剂都降低了土壤中有效镉（EDTA-Cd和Exch-Cd）的浓度，也降低了植物中Cd的含量（％）。这些修正案在八年后仍然有效，尽管随着时间的推移确实有所下降。在最初的几天里，赤泥加油菜秸秆（RMRS）的植物Cd减少量为83.5％，赤泥加玉米秸秆（RMCS）的减少量为65.3％，RS降低为50.9％，RM降低为54.0％，CS降低了37.3％年份。八年后，RMRS的植物Cd含量降低仍为17.2％，并且发现RMRS是降低Cd生物利用度的最有效方法。这项研究还解释了为什么植物Cd含量的减少随时间下降的原因是土壤中有效Cd含量随时间的变化，这对于指导农业实践很重要。结论是，RM，CS，RS及其与锌肥的有效改良剂组合对受Cd污染的土壤具有深远而持久的积极影响。