Farmers operate a machine to harvest wheats in Guanyuan Village of Tanghe County, Nanyang City, central China's Henan Province, May 27, 2019. (Xinhua/Feng Dapeng)

Aerial photo taken on May 27, 2019 shows harvesters working in wheat field in Tianzhuang Village of Tanghe County, Nanyang City, central China's Henan Province. (Xinhua/Feng Dapeng)

A farmer operates a machine to harvest wheat in Guanyuan Village of Tanghe County, Nanyang City, central China's Henan Province, May 27, 2019. (Xinhua/Feng Dapeng)

A harvester works in wheat field in Guanyuan Village of Tanghe County, Nanyang City, central China's Henan Province, May 27, 2019. (Xinhua/Feng Dapeng)

A farmer operates a machine to harvest wheat in Guanyuan Village of Tanghe County, Nanyang City, central China's Henan Province, May 27, 2019. (Xinhua/Feng Dapeng)

A farmer operates a machine to harvest wheat in Guanyuan Village of Tanghe County, Nanyang City, central China's Henan Province, May 27, 2019. (Xinhua/Feng Dapeng)

Farmers operate machines to harvest wheat in Tianzhuang Village of Tanghe County, Nanyang City, central China's Henan Province, May 27, 2019. (Xinhua/Feng Dapeng)

Farmers operate a machine to harvest wheat in Guanyuan Village of Tanghe County, Nanyang City, central China's Henan Province, May 27, 2019. (Xinhua/Feng Dapeng)

Aerial photo taken on May 27, 2019 shows a harvester working in wheat field in Tianzhuang Village of Tanghe County, Nanyang City, central China's Henan Province. (Xinhua/Feng Dapeng)

Aerial photo taken on May 27, 2019 shows a harvester working in wheat field in Tianzhuang Village of Tanghe County, Nanyang City, central China's Henan Province. (Xinhua/Feng Dapeng)

Aerial photo taken on May 27, 2019 shows a harvester working in wheat field in Tianzhuang Village of Tanghe County, Nanyang City, central China's Henan Province. (Xinhua/Feng Dapeng)

Aerial photo taken on May 27, 2019 shows a harvester working in wheat field in Tianzhuang Village of Tanghe County, Nanyang City, central China's Henan Province. (Xinhua/Feng Dapeng)

A farmer operates a machine to harvest wheat in Guanyuan Village of Tanghe County, Nanyang City, central China's Henan Province, May 27, 2019. (Xinhua/Feng Dapeng)

A farmer operates a machine to harvest wheat in Guanyuan Village of Tanghe County, Nanyang City, central China's Henan Province, May 27, 2019. (Xinhua/Feng Dapeng)