Surging exports of sweet potato and chilli to China have brought Vietnamese farmers their highest profit margins ever.

Sweet potato exports jumped nine times over the period to $2.1 million, while chili exports multiplied six times to $23 million, according to Vietnam Customs.

Rising demand in China prompted a surged in exports over the first 10 months that now has chili and sweet potato farmers reporting profits of VND200-300 million ($8,217-12,325) per hectare, more than they’ve ever made.

Farmers in the central highlands province of Gia Lai said prices on the two products have doubled year-on-year. Sweet potato is now at VND18,000-20,000 per kilogram, while chili is at VND25,000-55,000.

Vietnam and China signed a protocol on sweet potato in April this year, allowing the product to enter China under higher quality standards.

China also resumed the imports of chili from some Vietnamese companies after banning the produce for two years due to overuse of pesticides.

China now allows 14 types of agriculture produce from Vietnam to be imported officially, meaning that local exporters need to follow its strict standards concerning origins and packaging but will be able to sell more to Chinese buyers.

Vietnamese farmers have been raising their production quality in the last three years, and exports to China have therefore been rising fast.

In the first 10 months China imported $3.2 billion worth of vegetables and fruits from Vietnam, bringing agriculture imports to a new record of $7.5 billion. Vietnam now accounts for 10% of China’s agriculture imports.

Sweet potato and chili account for 86% of total vegetables and fruits exports to China.