Related Experiment Video
Updated: Jun 29, 2026
Repeatable Stair-step Assay to Access the Allelopathic Potential of Weedy Rice (Oryza sativa ssp.)
Published on: January 28, 2020
Screen low-accumulation rice varieties, and identify soil safety utilization thresholds in Cd/Hg-contaminated paddy
Shengting Rao1, Jian Wang2, Jiachun Shi1
1Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
This study identified low-cadmium/mercury (Cd/Hg) accumulating rice varieties and determined safe soil thresholds for rice production. Soil Cd and Hg thresholds were estimated at 0.15 mg/kg and 1.19 mg/kg, respectively, ensuring food safety.
Area of Science:
- Environmental Science
- Agronomy
- Food Safety
Background:
- Paddy soils co-contaminated with cadmium (Cd) and mercury (Hg) pose risks to rice safety.
- Limited knowledge exists on soil Hg thresholds for safe rice production and the stability of low-accumulating rice cultivars.
Purpose of the Study:
- To screen low-Cd/Hg accumulating rice varieties and assess their stability.
- To determine soil Cd and Hg concentration thresholds for safe rice production.
- To provide a scientific basis for managing Cd/Hg contaminated soils.
Main Methods:
- Field trials with 55 rice varieties across three years and sites.
- K-means clustering for variety classification.
- Genotype plus genotype-by-environment interaction (GGE) biplots for stability analysis.
- Species sensitivity distribution (SSD) modelling for threshold calculation.
Main Results:
- Some rice varieties exceeded national Cd standards, while Hg levels were generally within limits.
- Clustering identified low-Hg/Cd, low-Hg, low-Cd, and non-low-Hg/Cd rice varieties.
- Japonica rice cultivars NanJing-46 (S13) and XiuShui-14 (S26) showed low accumulation and high stability.
- Estimated soil Cd and Hg thresholds for safe rice production are 0.15 mg/kg and 1.19 mg/kg, respectively.
Conclusions:
- Screening low-Cd/Hg accumulating rice cultivars is feasible.
- Established soil thresholds provide a basis for managing contaminated agricultural soils.
- Findings support safe rice production and human consumption from affected areas.
