Right on Professor Hu Shuwen is salt-affected land after ecological treatment, compared with original saline-alkali land on the left. (Photo provided by Hu Shuwen)

By WANG Xiaoxia  TANG Zhexiao

Can you imagine transforming barren, salty soil into arable land in a month? This is not fantasy, but the actual result of research by Chinese scientists from China Agricultural University (CAU).

Hu Shuwen, professor at the College of Resources and Environmental Science of CAU, has developed a technique for rapid desalination and ecological treatment of saline-alkali soil by improving the soil structure.

During an exclusive interview with Science and Technology Daily, Hu said that his technique can desalinate soil in only one month, which has been demonstrated in many areas of China.

Major global challenge

Soil salinization is a global major challenge. According to the Global Map of Salt-affected Soils released by the Food and Agriculture Organization of the United Nations, more than 424 million hectares of topsoil (0-30 cm) and 833 million hectares of subsoil (30-100 cm) are salt-affected.

It is also a crucial issue in China. According to the data from the Chinese government, China has about 35 million hectares of saline-alkali land, of which about 14 million hectares have the potential for agricultural activities, accounting for more than 10 percent of the country's arable land.

Sustainable soil management practices shall be adopted to halt salinization and sodification.

Chinese President Xi Jinping said the comprehensive use of saline-alkali soil is of strategic importance to national food security. Xi made the remarks when visiting the Agricultural High-tech Industrial Demonstration Area of the Yellow River Delta on October 21.

In fact, China has long been committed to the restoration of saline-alkali soil. However, hardly any groundbreaking progress has been made until Hu and his team developed an innovative management system for saline-alkali soil.

The wheat in salt-affected land after ecological treatment is growing well. (Photo provided by Hu Shuwen)

Systematic soil improvement

Hu joined CAU in 2006, returning from the University of California, Irvine, where he worked as a researcher. He said that he wanted to share his knowledge and to do something for the motherland.

To solve the problem, one must figure out the cause of it, said Hu. So he promptly set about studying saline-alkali soil in the field.

During the study, he found that the particles of this kind of soil are so fine and closely attached that there is no room for water to permeate.

It's just like the water-proof cloth, said Hu, so the salt cannot leach out and is left in the plough layer of soil.

With an academic background in polymer science, Hu applied advanced polymeric materials to soil improvement. He and his team invented a natural polymeric soil conditioner that improves soil structure.

The soil conditioner transforms the fine particles into clots, between which there are channels for rainfall to soak into the ground and leach out the salt through underground drainage.

Besides, the research team also invented a controlled-release material to protect seeds from salt damage. Organic fertilizer, bacterial and fungal communities are applied to create a healthier soil environment. Supporting facilities are built near the fields to keep groundwater at a lower level, so as to prevent the reoccurrence of soil salinization. All these make up the systematic soil improvement technique, said Hu.

Compared with the traditional desalination methods via irrigation, the new technique is more efficient and sustainable, said Hu. It only takes one-thirteenth of the water compared to the previous method and remains long-term valid after improvement.

True knowledge comes from practice. Hu said that his team preferred to work in the field for eight months every year rather than staying in the lab. Seeing the crops grow from seedlings to harvest was a source of fulfillment, said Hu.

Professor Hu Shuwen is explaining his ecological treatment for saline-alkali soil.  (Photo provided by Hu Shuwen)

Working toward a better future

Since 2013, Hu's saline-alkali soil improvement technique has been promoted and demonstrated on a large scale in the Songnen Plain, coastal area and inland arid area.

With the technique, more than 7,000 hectares of saline-alkali land have been restored and utilized, and the benefited area has exceeded 70,000 hectares, with an annual increase in grain production of more than 300 million tons, said Hu.

Soil salinization is closely connected with drought. More than two-thirds of global salt-affected soils are found in arid and semi-arid climatic zones. Countries in Africa, central Asia and the Middle East are also facing the severe problem of soil salinization, said Hu, so the technique can benefit more countries and regions through international cooperation.

Through ecological restoration of newly added arable land in salt-affected areas and improvement of soil quality in poor land, it is not only conducive to increasing food production and safeguarding global food security, but also of great significance to enhancing biodiversity and achieving carbon neutrality.