Spring is an important season for farming. Though most parts of Shanghai are still in closed-off management, farmers on the city's outskirts have resumed cultivation and harvest.

One of the farmers is Gu Xiaoxiao, who was back to land in the beginning of April to collect his matured lettuce.

The growth cycle for lettuce is about a month and it is urgent for him to go back to the land.

"If we don't come back to harvest them, the lettuce will rot in the field," says Gu.

Gu's land is in Shanghai's suburban Qingpu district, where COVID 19 risks have been relatively low. Vegetable production was suspended in late March due to the COVID-19 outbreak.

But now all staff, from farmers to assembly workers and drivers are all back to work.

Every day, Gu's farm delivers more than 70 tonnes of vegetables from their farm to many closed-off compounds in the city center. The quantities are much higher than before the outbreak.

Wang Yin, general manager of Shanghai Runchen Agriculture Development which owns the farm, says Shanghai residents' demand of leafy greens is high.

"This season is when leafy greens come to the market and the supply is almost the same as last year's figure," says Wang.

The total area of the farm is more than 300,000 square meters planted with crops including cabbage and tomatoes. Each year, the farm can yield some 5,000 tonnes of crops and all of these go to Shanghai's city center.

With logistics delivery of vegetables from other parts of China facing challenges due to the pandemic, the resurgence of agriculture at farms in Shanghai is crucial.

Shanghai's farmland is more than 1,600 square kilometers, or about 25 percent of this metropolis' land area. Shanghai authorities said earlier that most of the city's farmers have gone back to land — the amount of crops in the field equals to the same amount last year.