Farmers in Soc Trang Province have been busy the last month harvesting what has been a bountiful water chestnut crop. 

Nguyen Van Quan, 44, of Nga Nam Town, and a hired worker have been harvesting water chestnut since early morning. Growing water chestnut is the main source of income for over 100 families in the area, including Quan's, who have been doing this for five years.

Nan, as water chestnut is called in Vietnamese, is a grass-like sedge that is harvested year-round and used like a vegetable by locals. The plant grows all over the Mekong Delta, but thrives in Bac Lieu and Soc Trang provinces.

According to Quan, growing water chestnut is quite easy because this hardy plant can withstand acidity in the soil and grows rapidly during the rainy season.

"In the past the plant was considered a weed, but that changed after it became popular in many neighboring provinces," the owner of a 5,000 sq.m farm said.

Harvesting the plant requires a lot of practice to ensure it does not break when pulled out of the water. Workers need to use just the right amount of force and choose only those that have sprouted about the length of an arm out of the water.

Quan has been hiring Tran Thi Ut Nhi, 49, to help him harvest for the last few years, and she said she gets paid VND100,000 ($4.28) for a three-hour shift. This is a common job in the neighborhood, especially for woman.

Normally, farmers harvest nan from early in the morning to 9 a.m. The harvested water chestnuts are placed in bins and dragged home to be sorted.

Quan stacks the water chestnut bundles neatly. Every day he harvests around 150 kg and sells them to traders for VND5,500 ($0.24) per kilogram.

He said there were plants available for harvest every day in April, allowing him to earn VND30 million ($1,280).

The plants are sorted, cut to 30 cm, washed, and bundled into stacks of 600 grams to one kilogram as required by traders.

During the sorting process, farmers regularly pour water on the water chestnuts to ensure they do not wilt.

A trader has come to Quan's farm to buy his harvest.

Local farmers said recently more traders have been coming to buy their nan and so they do not have to worry about overproduction. With the crop now fetching two or three times higher prices than rice, households that previously grew the grain have now switched to growing water chestnut.

A trader picks up nan to deliver to wet markets, supermarkets and restaurants in Soc Trang.

Water chestnut has white flesh after the outer layer is removed. Locals cook and eat it like a vegetable and use it in various hotpots. Farmers in Nga Nam Town hope it will become popular in cities in future.