A farmer fertilizes a field at a vegetable planting base in Haikou, south China's Hainan Province, Feb. 27, 2020. Farmers in Haikou are busy with agricultural production to ensure the supply of vegetables amid the fight against the novel coronavirus outbreak. (Photos: Xinhua)

Farmers harvest vegetables in a field at a vegetable planting base in Haikou, south China's Hainan Province, Feb. 27, 2020. Farmers in Haikou are busy with agricultural production to ensure the supply of vegetables amid the fight against the novel coronavirus outbreak.

A farmer ploughs in a field with a tractor at a vegetable planting base in Haikou, south China's Hainan Province, Feb. 27, 2020. Farmers in Haikou are busy with agricultural production to ensure the supply of vegetables amid the fight against the novel coronavirus outbreak.

Farmers harvest vegetables in a field at a vegetable planting base in Haikou, south China's Hainan Province, Feb. 27, 2020. Farmers in Haikou are busy with agricultural production to ensure the supply of vegetables amid the fight against the novel coronavirus outbreak.

A farmer waters vegetables in a field at a vegetable planting base in Haikou, south China's Hainan Province, Feb. 27, 2020. Farmers in Haikou are busy with agricultural production to ensure the supply of vegetables amid the fight against the novel coronavirus outbreak.

A farmer waters vegetables in a field at a vegetable planting base in Haikou, south China's Hainan Province, Feb. 27, 2020. Farmers in Haikou are busy with agricultural production to ensure the supply of vegetables amid the fight against the novel coronavirus outbreak.

A farmer works in a field at a vegetable planting base in Haikou, south China's Hainan Province, Feb. 27, 2020. Farmers in Haikou are busy with agricultural production to ensure the supply of vegetables amid the fight against the novel coronavirus outbreak.