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| Synergistic effects of an alkaline silicon-rich ameliorant and a low-cadmium-accumulating rice cultivar on the safe utilization of cadmium-contaminated paddy soils |
| Received:June 22, 2025 |
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| KeyWord:cadmium;rice;alkaline silicon-rich amendment;low-accumulation variety;safe utilization of paddy fields |
| Author Name | Affiliation | E-mail | | WANG Liang | Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences(CAS), Beijing 100101, China | | | LIU Jiabao | College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China | | | LIU Qiqing | Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences(CAS), Beijing 100101, China | | | YANG Baolin | Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences(CAS), Beijing 100101, China | | | LIAO Xiaoyong | Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences(CAS), Beijing 100101, China | liaoxy@igsnrr.ac.cn |
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| Abstract: |
| This study selected the locally dominant cadmium（Cd）-higher-accumulating cultivar Meixiangzhan（MXZ） from Qingyuan City, Guangdong Province and a low-Cd-accumulating cultivar Shenyou 9516（SY9516） as the experimental varieties. Through pot experiments conducted in moderately Cd-contaminated soil[total Cd （1.65±0.23） mg·kg-1], we explored the synergistic effects and mechanisms of combining the alkaline and silicon-rich compound amendment with the Cd low-accumulating cultivar. The results showed that planting SY9516 alone could reduce grain Cd content by 41.33% compared to MXZ（MXZ 0.75 mg·kg-1, SY9516 0.44 mg·kg-1）. The combination of SY9516 with the alkaline and silicon-rich amendment（AFS1） further reduced grain Cd content to 0.13 mg·kg-1, representing a 69.29% reduction compared to sole SY9516 cultivation, thus enabling safe grain production in the moderately Cd-contaminated farmland. This technology offers significant cost advantages, requiring only 6 540 yuan·hm-2. It also effectively improved the soil environment, increasing soil pH by 0.62 units, increasing available silicon by 40.75%, and decreasing exchangeable Cd by 46.11%. Structural equation modeling identified key regulatory pathways for Cd translocation and accumulation in the soil-rice system：Compared to the local variety MXZ, the low-Cd-accumulating cultivar SY9516 inherently elevated rhizosphere soil pH（by approximately 0.25 units）, thereby inhibiting Cd activation; The alkaline components promote the transformation of soil Cd from labile to more stable forms; The silicon-rich components reduce the Cd root-to-stem translocation coefficient by increasing available silicon in the rhizosphere（effective threshold range：400-650 mg·kg-1）. The study indicates that the combined application of alkaline silicon-rich composite amendment and a low-Cd-accumulating cultivar enables the safe production of rice in moderately Cd-contaminated farmland, with the synergistic mechanism primarily attributed to the joint enhancement of soil pH elevation, Cd form transformation, and silicon-mediated transport inhibition, achieved through the variety traits and the amendment. |
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