PLANT FACTORY: A staff member in Kingpeng Plant Factory inspects vegetables grown under artificial light sources on August 22 (ZHANG XU)

Sunshine, air and soil are indispensable for green plants. This might be axiomatic but not in a plant factory. By creating a plant factory, scientists are trying to grow plants where natural elements are deficient or absent, such as deserts, islands, water surfaces, South and North poles and space, as well as in human habitats such as skyscrapers in modern cities.

Recently, China's first large plant factory began operation in Beijing's Tongzhou District. It occupies an area of 1,289 square meters. By international standards, a plant factory exceeding 1,000 square meters is large.

The plant factory is widely considered the ultimate stage of agricultural industrialization. Biological, agricultural, computer information and mechanical automation technologies are used to increase the quantity and quality of plants manufactured in these factories. Until recently, only a few developed countries, such as Japan, the United States and the Netherlands, possessed such technologies.

The Tongzhou District factory was a research project funded by the Beijing Municipal Science and Technology Commission. It was co-developed and designed by Beijing Agricultural Machinery Institute and its spin-off, Beijing Kingpeng International High-tech Corporation. The two agencies own intellectual property rights related to the plant factory. The factory is a research and production base as well as a demonstration zone and technology incubator. It is considered China's agriculture Silicon Valley.

"Our factory uses the most cutting-edge planting technologies, most advanced instruments and equipment in the world, such as high-precision seedling cultivation production lines, transplantation robots, nutrient fluid automatic circulation and plant photosynthesis monitoring systems, environment control technologies and applied information management technologies," said Tian Zhen, Director of the Beijing Agricultural Machinery Institute.

From a distance, the glass and steel structure looks more like an aircraft carrier than a factory. All plants inside grow in a completely simulated environment, in controlled temperatures, moisture, lighting, carbon dioxide concentration and air currents.

Different from plants growing in fields, those in the factory spend every moment of their lives under a computer-controlled monitoring system. Data on necessary environmental conditions for plants to grow are stored in computers. Workers only need to set the required conditions such as the right temperature and moisture and a seedling culture box will provide seeds with their best environment to germinate.

Fruit and vegetables in the factory go through a tissue culture process. In this, technicians take the needed organs, tissues or cells from source plants, sterilize them and cultivate them in the laboratory.

"Seedlings obtained this way are uniform in size and retain the desirable traits of source plants," a staff member said. "Across the country, farmers' demands for quality seedlings are growing, so there is a big need for a plant factory dedicated to seedling cultivation," said Cheng Cunren, Deputy Director in Beijing Agriculture Machinery Institute, who participated in the design of the factory. In the future, different types of plant factories will be designed to meet diversified needs of different groups of people and people in various regions, Cheng said.

Plants in the factory grow in nutrient fluid rather than soil. Their shapes and flavors can be controlled by altering the nutrient fluid's composition. "Plants grow much faster in nutrient fluid than in soil, and they can be harvested several times a year," said Zhou Zengchan, Deputy General Manager and Chief Engineer of Beijing Kingpeng International High-tech Corporation.

The process from tissue cultivation to sowing and harvest takes only 20 to 30 days, more than 30 percent quicker than regular growth. Mature plants are harvested, automatically packaged by equipment according to customers' needs and stored in refrigerated warehouses. They are then ready to be sold at market.

Zhou said when the plant factory operates at full capacity, it can produce high quality vegetables and fruits grown from 15 million seedlings obtained through machine sowing and 100,000 through tissue culture each year.

In a seedling cultivation chamber, about 5,000 to 6,000 lettuce seedlings can grow in a square meter. The unit output is 10 times that of a natural environment. Shelves on which the seedlings grow can be stacked and moved around, often increasing the planting areas by several times.