A farmer prepares a rice field in Mekong Delta's Soc Trang province which was affected by the sediment, Vietnam, May 25, 2022. REUTERS/Athit Perawongmetha 

A farmer prepares a rice field in Mekong Delta's Soc Trang province which was affected by the sediment, Vietnam, May 25, 2022. REUTERS/Athit Perawongmetha 

Farmers prepare former rice fields into pools to farm shrimps in Soc Trang province, Vietnam, April 28, 2021. Picture taken April 28, 2021. REUTERS/Thanh Hue 

A farmer plants rice on a paddy field during early morning to avoid the heat in Hanoi, Vietnam June 25, 2020. REUTERS/Kham 

Farmers plant rice on a paddy field during early morning to avoid the heat in Hanoi, Vietnam June 25, 2020. REUTERS/Kham 

Farmers plant rice on a paddy field during early morning to avoid the heat in Hanoi, Vietnam June 25, 2020. REUTERS/Kham 

Farmers plant rice on a paddy field during early morning to avoid the heat in Hanoi, Vietnam June 25, 2020. REUTERS/Kham 

A farmer plants rice on a paddy field during early morning to avoid the heat in Hanoi, Vietnam June 25, 2020. REUTERS/Kham 

Farmers plant rice on a paddy field during early morning to avoid the heat in Hanoi, Vietnam June 25, 2020. REUTERS/Kham 

An ethnic Thai farmer works on her terraced rice field in Pu Luong, Vietnam February 29, 2020. Picture taken February 29, 2020. REUTERS/Kham 

An ethnic Thai farmer works on her terraced rice field in Pu Luong, Vietnam February 29, 2020. Picture taken February 29, 2020. REUTERS/Kham 

A farmer harvests rice in a paddy field outside Hanoi, Vietnam June 10, 2019. REUTERS/Kham 

A farmer harvests rice by a paddy field outside Hanoi, Vietnam June 10, 2019. REUTERS/Kham 

A farmer harvests rice by a paddy field outside Hanoi, Vietnam June 10, 2019. REUTERS/Kham 

A farmer harvests rice by a paddy field outside Hanoi, Vietnam June 10, 2019. REUTERS/Kham TPX IMAGES OF THE DAY 

A farmer harvests rice on a rice paddy field outside Hanoi, Vietnam, June 7, 2018. REUTERS/KhamÊ 

A farmer harvests rice on a rice paddy field outside Hanoi, Vietnam, June 7, 2018. REUTERS/KhamÊ 

A farmer harvests rice on a rice paddy field outside Hanoi, Vietnam, June 7, 2018. REUTERS/KhamÊ 

A farmer works on a rice paddy field in Quang Ngai province, Vietnam March 14, 2018. REUTERS/Kham TPX IMAGES OF THE DAY 

A farmer works on a rice paddy field in Quang Ngai province, Vietnam March 14, 2018. REUTERS/Kham 

Farmers harvest rice on a flooded field after a heavy rainfall caused by a tropical depression in Ninh Binh province, Vietnam October 14, 2017. REUTERS/Kham 

Farmers harvest rice on a flooded field after a heavy rainfall caused by a tropical depression in Ninh Binh province, Vietnam October 14, 2017. REUTERS/Kham 

A farmer harvests rice ahead of Doksuri storm in Thanh Hoa, Vietnam, September 14, 2017. REUTERS/Kham 

A farmer harvests rice ahead of Doksuri storm in Thanh Hoa, Vietnam, September 14, 2017. REUTERS/Kham 

A farmer talks on a cell phone while working on a rice paddy field outside Hanoi, Vietnam July 3, 2017. REUTERS/Kham 

A farmer shows her Nokia cell phone on a rice paddy field outside Hanoi, Vietnam July 3, 2017. REUTERS/Kham 

A farmer reads a message on a cell phone while working on a rice paddy field outside Hanoi, Vietnam July 3, 2017. REUTERS/Kham 

A farmer reads a message on a cell phone while working on a rice paddy field outside Hanoi, Vietnam July 3, 2017. REUTERS/Kham 

Farmers plant rice on a rice paddy field in Ha Tinh province, Vietnam February 4, 2017. REUTERS/Kham 

Farmers plant rice on a rice paddy field in Ha Tinh province, Vietnam February 4, 2017. REUTERS/Kham 

A farmer harvests rice at Muong Thanh valley, in Dien Bien province, Vietnam June 7, 2016. Picture taken June 7, 2016. REUTERS/Kham 

Farmers work on a terraced paddy field for the new rice season in Vietnam's northern Mu Cang Chai district, 360 km (225 miles) northwest of Hanoi June 6, 2016. REUTERS/Kham 

A farmer works on a terraced paddy field for the new rice season in Vietnam's northern Mu Cang Chai district, 360 km (225 miles) northwest of Hanoi, June 6, 2016. REUTERS/Kham 

Farmers work on a terraced paddy field for the new rice season in Vietnam's northern Mu Cang Chai district, 360 km (225 miles) northwest of Hanoi June 6, 2016. REUTERS/Kham 

A farmer burns his dried-up rice on a paddy field stricken by drought in Soc Trang province in Mekong Delta in Vietnam March 30, 2016. REUTERS/Kham 

A farmer burns his dried-up rice on a paddy field stricken by drought in Soc Trang province in the Mekong Delta in Vietnam March 30, 2016. REUTERS/Kham/File Photo 

A farmer burns his dried-up rice on a paddy field stricken by drought in Soc Trang province in the Mekong Delta in Vietnam March 30, 2016. Photo taken on March 30, 2016. REUTERS/Kham 

Farmers plant rice on a paddy in Vietnam's northern Phu Tho province, outside Hanoi, February 21, 2016. REUTERS/Kham 

Farmers plant rice on a paddy in Vietnam's northern Phu Tho province, outside Hanoi, February 21, 2016. REUTERS/Kham 

Farmers plant rice on a paddy in Vietnam's northern Phu Tho province, outside Hanoi, February 21, 2016. REUTERS/Kham 

A farmer transports a basket of fertilizer while planting rice on a paddy in Vietnam's northern Phu Tho province, outside Hanoi, February 21, 2016. REUTERS/Kham 

Farmers from the Hmong ethnic tribe pour rice into the wind to separate low quality grains during harvest season in Mu Cang Chai, northwest of Hanoi, October 4, 2015. REUTERS/Kham 

Farmers from the Hmong ethnic tribe walk on a terraced rice paddy field during the harvest season in Mu Cang Chai, northwest of Hanoi, October 4, 2015. REUTERS/Kham 

A farmer from the Muong ethnic tribe burns rice straw during the harvest season in Tan Son, outside Hanoi, October 4, 2015. REUTERS/Kham 

A Vietnamese farmer of Hmong ethnic tribe pours rice into the wind to separate low quality grains during the harvest season in Mu Cang Chai, northwest of Hanoi October 3, 2015. REUTERS/Kham 

Vietnamese farmers of Hmong ethnic tribe pour rice into wind to separate low quality grains during the harvest season in Mu Cang Chai, northwest of Hanoi October 3, 2015. REUTERS/Kham 

A Vietnamese farmer of Hmong ethnic tribe Hang A Dua uses an umbrella to cover his 4-months-old son Hang Trung Hieu from the sun on a terraced paddy field during the harvest season in Mu Cang Chai, northwest of Hanoi October 3, 2015. REUTERS/Kham 

A Vietnamese woman of Hmong ethnic tribe carries a grass basket on a terraced rice paddy field during the harvest season in Mu Cang Chai, northwest of Hanoi October 3, 2015. REUTERS/Kham 

Vietnamese farmers of Dao ethnic tribe harvest rice on a terraced rice paddy field during the harvest season in Tu Le, northwest of Hanoi October 3, 2015. REUTERS/Kham 

A farmer harvests rice on a paddy field in Vinh Ngoc village, outside Hanoi, Vietnam June 2, 2015. Vietnam, the world's third-largest rice exporter after India and Thailand, has raised the export price floor for the 25 percent broken rice by 3 percent to $350 a tonne as it prepares for a tender in the Philippines, traders said on Monday. REUTERS/Kham 

A farmer harvests rice on a paddy field in Vinh Ngoc village, outside Hanoi, Vietnam June 2, 2015. Vietnam, the world's third-largest rice exporter after India and Thailand, has raised the export price floor for the 25 percent broken rice by 3 percent to $350 a tonne as it prepares for a tender in the Philippines, traders said on Monday. REUTERS/Kham 

A farmer carries rice on his shoulder during the harvest season on a paddy field in Vinh Ngoc village, outside Hanoi, Vietnam June 2, 2015. Vietnam, the world's third-largest rice exporter after India and Thailand, has raised the export price floor for the 25 percent broken rice by 3 percent to $350 a tonne as it prepares for a tender in the Philippines, traders said on Monday. REUTERS/Kham 

Farmers process rice while harvesting near a paddy field in Vinh Ngoc village, outside Hanoi, Vietnam June 2, 2015. Vietnam, the world's third-largest rice exporter after India and Thailand, has raised the export price floor for the 25 percent broken rice by 3 percent to $350 a tonne as it prepares for a tender in the Philippines, traders said on Monday. REUTERS/Kham 

A farmer carries rice on his shoulder during the harvest season on a paddy field in Vinh Ngoc village, outside Hanoi, Vietnam June 2, 2015. Vietnam, the world's third-largest rice exporter after India and Thailand, has raised the export price floor for the 25 percent broken rice by 3 percent to $350 a tonne as it prepares for a tender in the Philippines, traders said on Monday. REUTERS/Kham 

A farmer tends cows at a paddy field in Ninh Binh province, south of Hanoi, Vietnam, May 13, 2015. In Vietnam, the world's third-largest rice exporter after India and Thailand in 2014, prices edged up due to prospects of a possible tender in the Philippines, traders said. REUTERS/Kham 

Farmers dry rice on top of a dike in Ninh Binh province, south of Hanoi, Vietnam, May 13, 2015. In Vietnam, the world's third-largest rice exporter after India and Thailand in 2014, prices edged up due to prospects of a possible tender in the Philippines, traders said. REUTERS/Kham 

Farmers harvest rice at a paddy field in Ninh Binh province, south of Hanoi, Vietnam on May 13, 2015. In Vietnam, the world's third-largest rice exporter after India and Thailand in 2014, prices edged up due to prospects of a possible tender in the Philippines, traders said. REUTERS/Kham 

A farmer transports sand for construction, through a rice paddy field in Ninh Binh province, south of Hanoi, Vietnam May 7, 2015. Photo taken on May 7, 2015. REUTERS/Kham

A farmer tends her water buffalos on a rice paddy field in Ninh Binh province, south of Hanoi, Vietnam May 7, 2015. Photo taken on May 7, 2015. REUTERS/Kham

A farmer sprays chemical pesticide on a rice paddy field in Ninh Binh province, south of Hanoi, Vietnam May 7, 2015. Photo taken on May 7, 2015. REUTERS/Kham