Li Xiushuang and her husband work in one of their greenhouses in Dezhou, Shandong. ZHANG ZHENXU/FOR CHINA DAILY

Li Xiushuang, 39, and her husband are among those who have returned to rural areas to use new technology to develop agricultural businesses.

In 2010, Li returned to her hometown of Laocheng, Wucheng county in Dezhou city, Shandong province, after graduating from Dezhou University in 2005, where she studied agronomy — the science of soil management and crop production.

She and her husband now grow crops such as lettuce, celery and tomatoes in three greenhouses that use hydroponic technology.

They also have four greenhouses where vegetables are grown in a soilless mix base. These greenhouses produce vegetables worth 1 million yuan ($145,600) annually.

Five years ago, when the couple developed an interest in growing vegetables in greenhouses equipped with hydroponic technology, Li doubted whether the venture would succeed.

"But my husband insisted, and said hydroponic vegetables cater to public demand for healthy food," she said.

The couple rented a greenhouse to give the venture a try, and also attended South China Agricultural University in Guangzhou, capital of Guangdong province, for a time to learn about plant nutrition.

After 18 months' work, their first greenhouse equipped with hydroponic technology started operating in 2019, producing a type of cabbage.

"It takes 20 days for the cabbages to grow in the nutrient-rich water solution, and we produce the crops all year around," Li said, adding that by recycling the water through the system, at least 90 percent less water is used than in soil-based methods.

The cabbages have sold well, and Li and her husband have added two hydroponic greenhouses to their business.

"Many people ask us if we use hormones on the crops, as the cabbages grow so fast," she said.

"To reassure our customers, we developed aquaponic systems to produce fish and vegetables from the same water source."

Water containing fish waste is pumped to the vegetable-growing area from a pond that is home to thousands of fish. The waste fertilizes the crops as microorganisms break down ammonia produced by the fish. The plants absorb the nutrients, clean the water of toxic ammonia, and the clean water flows back to the pond.

"With the correct proportion of plants to fish, an aquaponic system is highly sustainable for growing vegetables," Li said.

This year, she and her husband plan to expand their business by adding 10 greenhouses and two ponds.

"We also plan to develop two greenhouses where children can try their hand at farming and learn about growing vegetables," Li said.