Biochar Could Help Make Tea Farming Cleaner, Safer, and More Climate Resilient

Tea is one of the world’s most widely consumed beverages, but the soils that sustain tea plantations are under growing pressure. Long-term fertilizer use, monocropping, soil acidification, nutrient loss, heavy metal contamination, and climate stress are threatening both tea productivity and environmental safety. A new review published in Biochar examines how biochar, a carbon-rich material produced by heating biomass under limited oxygen, could become a practical tool for more sustainable tea cultivation.

“Tea farming depends on healthy soil, but many tea-growing regions are facing serious soil degradation and contamination risks,” said corresponding author Md Shafiqul Islam. “Our review shows that biochar can help address several of these challenges at the same time, from improving soil fertility to reducing the movement of toxic metals into tea leaves.”

Tea plants often grow in acidic, nutrient-poor soils. Intensive management can worsen acidity, wash away essential nutrients, and increase the mobility of toxic metals such as cadmium, lead, and arsenic. These problems can weaken plant growth and raise food safety concerns. The review synthesizes recent field and laboratory studies on the biochar, soil, and tea nexus, focusing on five connected areas: soil properties, microbial communities, nutrient cycling, tea productivity and quality, and heavy metal detoxification.

The authors report that biochar can buffer soil acidity, increase cation exchange capacity, improve soil structure, enhance water retention, and reduce nutrient leaching. These changes create a more favorable root environment for Camellia sinensis, the plant used to produce tea. Biochar can also provide habitat for beneficial microorganisms and shift microbial communities toward groups that support nutrient turnover, carbon cycling, and soil resilience.

Biochar may also improve the efficiency of fertilizer use. By holding ammonium, phosphorus, potassium, calcium, and magnesium in the root zone, biochar can help tea plants access nutrients more effectively while reducing losses to leaching or gas emissions. Some studies reviewed by the authors showed improvements in root development, leaf biomass, shoot density, bud weight, and tea yield when biochar was used alone or with organic and mineral fertilizers.