Rice is a daily staple for billions of people, but in some agricultural regions, the soil itself poses a hidden threat. Cadmium, a toxic heavy metal naturally present in certain geological formations, can accumulate in rice grains and enter the human food chain. At the same time, selenium, an essential nutrient for human health, may remain trapped in the soil and unavailable to crops.
Now, researchers have discovered that specially designed biochar-based soil amendments can address both challenges simultaneously, reducing cadmium accumulation in rice by up to 85.4% while increasing selenium levels by up to 357.5%.
The findings, published in the journal Biochar, demonstrate a practical strategy for improving both food safety and nutritional quality in rice-producing regions affected by naturally elevated metal concentrations.
"Our findings suggest that soil management can do more than simply reduce harmful contaminants. By carefully regulating soil chemistry, we can also improve the nutritional value of crops, creating opportunities for safer and healthier food production," said corresponding author Professor Deyi Hou of Tsinghua University.
Tackling two challenges with one solution
The research team conducted field experiments in a karst region of Southwest China, where limestone-derived soils naturally contain elevated concentrations of cadmium and selenium.
Unlike pollution caused by industrial activities, these naturally occurring elements cannot be easily eliminated by controlling external contamination sources.
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