By 2020, soil remediation will drive the environmental protection industry to increase its output value by about 450 billion yuan.

　　Air pollution can be blown away by rain, and water pollution can follow river of no return, but once the soil is polluted, it will last forever. Choking smog and discolored river water mean the existence of air and water pollution, but it is difficult for ordinary people to distinguish polluted land from its appearance. Historically, soil pollution appeared together with water pollution and air pollution, but due to many problems such as complex causes, unclear rights and responsibilities, insufficient sources of funds and unclear profit model, the related governance has long lagged behind the governance of water and air.

　　In May 2016, the State Council promulgated the Action Plan for Prevention and Control of Soil Pollution ("Soil Ten Articles"), which opened the curtain of soil remediation. In November of the same year, the draft of the Law on the Prevention and Control of Soil Pollution was released, and the system design of prevention and protection, control and restoration was initially determined. In March this year, the Ministry of Agriculture issued the implementation opinions on implementing the "Ten Articles of Soil" and deployed to strengthen the prevention and control of soil pollution in agricultural land. The publication of a series of documents makes people pay great attention to the soil remediation industry.

　　Who comes first in prevention, control and restoration?

　　In the eyes of many people, contaminated soil remediation is a big cake in the environmental protection industry. Many people in the industry have estimated that the scale of the industry driven by it will reach several trillion yuan. With the introduction of "Ten Articles of Soil" and its supporting documents, it is found that it will take time for the industry to reach the target scale. According to the data provided by the Land Remediation Center of the Ministry of Land and Resources, the output value of soil pollution remediation industry in China is less than 1% of the total output value of environmental protection industry. The relevant person in charge of the Ministry of Environmental Protection also said that the document will promote the development of related industries such as soil environmental quality monitoring, investigation, evaluation, remediation and equipment and drug production. By 2020, it is estimated that the new output value of the environmental protection industry will be about 450 billion yuan.

　　Large-scale soil treatment is a worldwide problem, and its complexity and investment are far greater than air and water. The more difficult governance is, the more important prevention and control is. According to Chen Nengchang, a researcher at Guangdong Institute of Ecological Environment and Soil, the publication of a series of documents marks the change of the concept of soil pollution prevention and control in China, from one-size-fits-all index control to comprehensive prevention and control that emphasizes prevention first and risk control. The experience of soil pollution control in developed countries shows that the investment ratio of pollution prevention, risk management and control, and remediation is roughly 1∶10∶100. He believes that the essence of soil pollution prevention and control is to classify and rationally use land on the basis of protecting soil. Simple soil remediation is the last and last resort.

　　If soil pollution can’t be cured, it needs "pulse" first, and "prescription" is not just a dose of soil remediation. According to the plan of the Ministry of Agriculture, on the basis of detailed investigation and monitoring of cultivated land soil pollution, the environmental quality of cultivated land should be divided into three categories: priority protection, safe utilization and strict control, and classified management of cultivated land soil environmental quality should be implemented. Give priority to the protection of unpolluted and slightly polluted cultivated land, use moderately and slightly polluted cultivated land safely, and strictly control heavily polluted cultivated land. This means that for cultivated land with slight pollution, the planting structure can be adjusted and trees that do not absorb heavy metals can be planted; For those with particularly serious pollution, risk control, fallow farmland or ecological migration can be implemented instead of one-size-fits-all soil remediation.

　　At present, the central government has set up a special fund for the prevention and control of soil pollution, which is mainly used for the investigation, restoration and treatment of soil pollution. The Ministry of Agriculture has successively carried out pilot projects in Tianjin, Guangxi, Hunan and other places to control and repair heavy metal pollution in agricultural products producing areas, and launched demonstration projects for pollution remediation in nine polluted areas. For typical crops and pollutants, a demonstration area for comprehensive control and restoration of cultivated land pollution will be built, and 10 million mu of polluted cultivated land will be controlled and restored before the end of 2020.

　　Where does the repair fund come from?

　　Hechi City, Guangxi is one of the six pioneering areas for comprehensive prevention and control of soil pollution in China, which is determined by "Ten Articles of Soil". Sixteen years ago, a heavy rainstorm caused a tailings dam in Huanjiang County of the city to break, and tens of thousands of mu of cultivated land along the coast were polluted by heavy metals. In order to repair cultivated land, farmers once adopted the original method of sprinkling lime, but with little effect. According to the local characteristics, in 2005, the Institute of Geographical Resources of Chinese Academy of Sciences developed the intercropping restoration technology of super-enriched plants and economic plants. The government distributed Pteris vittata seedlings, Sedum alfredii seedlings and mulberry seedlings to the villagers free of charge to guide them in planting. Pteris vittata and Sedum alfredii are super-enriched plants, which have strong absorption capacity for heavy metals. By enriching heavy metals in stems and leaves, heavy metals in soil are taken away.

　　After the technology was mature, in 2010, with the support of 24.5 million yuan of central special funds for the prevention and control of heavy metal pollution, the soil pollution control project around the Yangtze River was launched, which was the first farmland soil remediation project in Guangxi. With the mode of "local government leading, technical support from scientific research institutions and farmers’ active participation", the project has restored a total of 1280 mu of polluted farmland. Five years later, the output of agricultural products in the treatment area reached more than 90% of the local normal level, and the qualified rate of heavy metals in agricultural products reached 95%, and the project passed the acceptance. In the past, the cultivated land with no grain harvest is now a lush mulberry field.

　　The causes of soil pollution are complex, the treatment is difficult and the period is long, which requires huge financial support. The data show that from 2007 to 2015, among the 316 soil remediation projects with a total investment of about 9 billion yuan in China, the amounts from financial funds, self-raised funds and the combination of financial and self-raised funds were 63%, 14% and 21% respectively. "Remediation funds mostly come from finance, and it is difficult to form a reasonable profit model, which restricts the development of soil remediation industry. We must speed up the exploration of the market-oriented development of soil pollution remediation. " Xu Minggang, deputy director of the Division of Agricultural Resources of China Academy of Agricultural Sciences, suggested that socialized governance should be strengthened, and the promised governance mode that the governance effect is linked to fees can be adopted.

　　"The pioneering area for comprehensive prevention and control of soil pollution itself is to innovate. Whether it is PPP or third-party governance, there must be predictable returns." The relevant person in charge of Hechi City Environmental Protection Bureau said that on the basis of the existing PPP model exploration pilot, the value of land resources development and utilization should be used as a bridge to integrate the restoration of polluted sites with the development of construction land, the restoration of polluted farmland with the development of planting industry, attract social capital investment, and the government and enterprises jointly control soil pollution and share the benefits of land development and utilization.

　　Where to find a good way to cure the soil?

　　"China’s research and development of soil remediation technology is about 20 years later than that of developed countries in Europe and America. There is still a big gap in remediation technology, equipment and application, which restricts the industrial development of domestic soil remediation technology." Liu Zhengjun, chairman of Hunan Yongqing Environmental Protection Group, said that at present, a considerable part of China’s restoration technologies and equipment are imported from abroad, which is expensive to purchase, high in equipment maintenance cost and poor in economy. Due to the differences in soil types and pollution levels, these technical equipment are "acclimatized". This requires domestic enterprises to develop practical remediation technologies and equipment with independent intellectual property rights and suitable for the characteristics of polluted soil in China.

　　Xu Minggang introduced that the treatment of heavy metal pollution in soil at home and abroad mainly starts from two aspects: first, activation means, that is, increasing the solubility and mobility of heavy metals, transferring heavy metals from soil solid phase to soil liquid phase through soil leaching, and then recycling and treating wastewater rich in heavy metals, which is also the main method adopted for heavy metal treatment in urban land at present. The second is passivation, that is, changing the existing forms of heavy metals in soil and reducing the bioavailability of heavy metals, thus reducing the absorption of heavy metals by crops. From the point of view of agricultural production, passive means is more in line with the development level of agriculture in China at this stage, which is economical, reliable and easy for farmers to master, and is conducive to large-scale promotion.

　　At present, the agricultural sector has launched a pilot application of typical farmland pollution control and remediation technology. Based on the type, degree and regional representativeness of soil pollution, pilot projects for the treatment and restoration of polluted paddy fields, vegetable fields and dry land will be implemented in batches in typical cultivated land pollution areas. According to the pilot situation, a number of applicable technologies with low cost, good effect and easy popularization will be formed, and a catalogue of recommended technologies for farmland management and restoration will be compiled and published.

　　Relevant experts told reporters that technology should be tailored to local conditions and comprehensively implemented. Taking the heavy metal pollution of cultivated land as an example, the cost of comprehensive restoration is high, such as repairing an acre with the method of alien soil, which costs hundreds of thousands of yuan; Some take a long time, for example, it takes decades for plants to absorb heavy metals. Therefore, it is necessary to reasonably select one or more technologies such as external pollution isolation, irrigation water purification, low accumulation variety screening and application, water and fertilizer regulation, soil conditioning, alternative planting and so on according to the situation, so as to gradually realize crop safety production.

　　Economic Daily China Economic Net reporter Qiao Jinliang