A farmer trims a winter jujube tree in Binzhou City, east China's Shandong Province, March 1, 2019. (Photos: Xinhua)

A farmer works at a greenhouse in Yiyuan County, Zibo City, east China's Shandong Province, March 1, 2019.

A farmer pollinates peach flowers at a greenhouse in Yiyuan County, Zibo City, east China's Shandong Province, March 1, 2019.

Farmers work at a greenhouse in Gengdian Village, Liaocheng City, east China's Shandong Province, March 1, 2019.

Farmers plant tomato seedlings at a greenhouse in Shazhou Village, Shiyan City, central China's Hubei Province, March 1, 2019.

Farmers work at a greenhouse in Gengdian Village, Liaocheng City, east China's Shandong Province, March 1, 2019.