Cadmium remediation solution for durian orchards – An opportunity to restore cultivation areas in Đồng Tháp

The Chinese market consumes 97% of Vietnam’s durian exports. When this country increased heavy metal controls, durian exports in the first 5 months of 2025 sharply decreased, reaching only 387 million USD (down 58%) and garden purchase prices plummeted. One of the reasons is the residue of cadmium (Cd) in the soil and fruit exceeding the limit.

Why are durian gardens contaminated with Cadmium?

Soil science experts say that durian growing soil in the Mekong Delta (MD) is being degraded and polluted, accumulating Cadmium and pesticide residues. Acidic, infertile soil combined with the overuse of chemical fertilizers and flowering stimulants accelerates the accumulation process. This is the main reason why China has tightened inspections, leading to a sharp decline in exports.

Dong Thap pioneers solution testing

To save the export market, Dong Thap province Dong Thap has implemented a model to remediate cadmium-contaminated soil at two households in Thanh Hung and Long Tien communes. Each household applies technical solutions on a 0.1 ha plot:

1. Integrated intensive farming with fertilizers with low cadmium content

2. Combine solution 1 with planting mint to absorb cadmium

3. Combine solution 1 with biological products to limit plant absorption of metals

4. Combine solution 1 with activated carbon (biochar) to raise pH and adsorb cadmium.

5. Combine biochar and biological products with integrated intensive farming
   
   

Results and lessons learned

After 4 months of implementation, soil pH increased from 4.5 to 5, and cadmium in branches and leaves significantly decreased in solutions 1–3. Specifically, the integrated intensive farming solution reduced cadmium to 0.01 mg/kg, while planting mint and biological products reduced cadmium to 0.02 mg/kg. However, the solution using biochar (4–5) did not help reduce cadmium content in leaves.

Experts initially commented that the model brought positive signals, but it is necessary to continue monitoring cadmium content in the fruit – a decisive factor for meeting export standards. At the same time, the choice of solution needs to be based on the specific conditions of each garden, as not all options are equally effective.

Recommendations for farmers

• Reduce chemicals, protect soil health: Use organic fertilizers, microbial fertilizers, and avoid overusing pesticides to limit cadmium accumulation.

• Prioritize safe fertilizers: Choose fertilizers with low cadmium content and apply the correct dosage; combine integrated intensive farming, as in solution 1, to improve pH and reduce cadmium.

• Plant metal-absorbing crops: In addition to mint, farmers can plant mustard greens and vetiver grass to absorb cadmium and improve the soil.

• Regularly check soil and fruit: Coordinate with specialized agencies to take soil, water, and fruit samples to check for cadmium before export.

Conclusion

The cadmium detoxification model in Dong Thap shows that, with a reasonable intensive farming process and clean fertilizer sources, farmers can improve soil pH and reduce cadmium in durian trees. Although it still needs time to evaluate the effectiveness on fruit and replicate, this is sustainable direction king fruit