Pan Renguo, a farmer in northeast China, has come to know the value of his organic vegetables.

The chili peppers and cabbage grown by Pan and his fellow villagers sold well this summer, even to customers more than 1,000 km away in Beijing and Hebei Province, earning gross revenue of 36 million yuan (5.2 million U.S. dollars) for their cooperative in Heilongjiang Province.

Their village in Suihua City was one of the pilot areas selected last year to promote black soil protection through erosion control and increased organic matter in soil.

"With the use of organic fertilizers, the chili peppers contain more vitamin C and taste good," said Pan, president of the Xinnuo fruit and vegetable cooperative.

Monday was World Soil Day. The black soil in China's northeast, which was once fertile, has been degraded in the region due to excessive use of chemical fertilizers and long-term cultivation, threatening stable output.

In Suihua's Hailun City, the content of organic matter in local black soil has fallen to 4 percent from 5.8 percent 30 years ago, according to Wang Yanbing, an agricultural official.

"If the trend continues, crops will not grow well anymore," he warned.

More than half of the cultivated soil faces erosion in Hailun.

Black soil in other parts of the region has also undergone decreases in organic matter.

In 2015, China launched a pilot black soil protection project in 17 grain-producing counties in the northeast, which also includes Inner Mongolia, and the provinces of Jilin and Liaoning. The scheme is aimed at improving the fertility of degraded soil.

Many farmers like Pan have benefited from the project as crops such as organic rice earn them more, while also decreasing use of chemical fertilizers and pesticides.

Heilongjiang plans to cut the use of chemical fertilizers, pesticides and herbicides by 10 percent, 20 percent and 30 percent respectively by 2020 from 2015 levels.

New technology has been developed to meet the goals.

In many paddies in Suihua, insect traps have been installed to kill pests, while tools have been upgraded to reduce the use of fertilizers.

But high costs have affected farmers' willingness to protect the soil. For example, deep plowing is good for the restoration of soil and burying straw, but it means higher costs despite government subsidies.

More research investment is needed to develop new technology for protecting black soil such as rapid composting under low temperatures, said Han Xiaozeng, a researcher with the Chinese Academy of Sciences.

According to the latest figures from the Ministry of Environmental Protection and the Ministry of Land and Resources, about 16.1 percent of China's surveyed land suffers from excessive levels of pollution, and 19.4 percent of surveyed arable land had levels of pollution higher than the national standard.

In May, the State Council released an Action Plan for Soil Pollution Prevention and Control, which aims to improve soil quality, ensure safe agricultural products and a healthy living environment for people.

Under the document, China will curb worsening soil pollution by 2020, put soil pollution risks under control by 2030, and create a virtuous cycle in the ecosystem by 2050.

The central province of Hunan, the country's largest rice producer, has planned to set up pilot fallow zones on 6,600 hectares of rice fields to help soil recover from heavy metal pollution.

In these zones, farmers stop planting and use lime and green fertilizers and plant pollutant-absorbing crops. The government provides them subsides.

"The fallow and crop rotation measures are good for rehabilitation and sustainable agricultural development," said Zhong Wuyun of the provincial agricultural committee.

In November, nine provinces and regions, including Hunan, began to adopt fallow and crop rotation measures in pilot areas, covering 410,000 hectares of arable land.

Meanwhile, the country is drafting a law on soil pollution prevention and treatment to push the protection efforts.

"We should also encourage social institutions to participate in soil environment monitoring and form industrial chains in treatment and restoration projects," said Gao Shengda, an environmental expert.