Pollution and overuse of arable land has reached crisis levels, according to experts from Chinese Academy of Engineering (CAE) cited by Economic Weekly. Urgent work is needed to grade soil by quality, identify remediation technologies and techniques, and advance the regulatory framework around arable land, the report adds.
While domestic food production accounts for 16 percent of the world total, fertiliser use has reached 31 percent of world total, says Lin Weilun 林伟伦 CAE fellow and Beijing Forestry University professor. Estimates place fertiliser use at four times the appropriate level. Annual pesticide use is in excess of 1.8 million tonnes, but effective utilisation rate is under 30 percent, continues Lin. The rest is not utilised and instead runs off or accumulates in soil, contributing to pest resistance. While chemical agriculture can result in short term yield increases, in the long term, it has a severe impact on soil, environment, and food quality and safety, he adds.
Areas irrigated with wastewater are at high risk of being contaminated with heavy metals, according to data from a cited Ministry of Agriculture (MoA) soil survey. In survey data from 1.4 million hectares of wastewater irrigation area, 64.8 percent of land tested positive for heavy metal contamination. Wastewater irrigation has stopped in most areas, but these pollutants are difficult and costly to extract from soil. Soil remediation costs at a Beijing chemical plant redeveloped for real estate were in excess of C¥700 million, says the piece. A recent incident involving cadmium-tainted wheat is discussed.
Farmland is 'worked to death', says Meng Wei 孟伟 CAE fellow, and China's soil suffers from overuse and overdraft of soil.
Soil pollution is not as severe as some developed countries due to the shorter history of industrial production, says Wei Fusheng 魏复盛 CAE fellow and China Environmental Monitoring Station researcher. While over 90 percent of farmland land remains suitable for cultivation, 2.6 percent of farmland is moderately or severely polluted, he says. An additional 11 percent is slightly polluted. Wei recommends
- developing classification measures to clearly categorise type and degree of soil pollution
- using classifications to regulate whether and how land is used
- using classifications to carry out monitoring and remediation work
- modernising agricultural production
- moving towards sustainable agriculcture
- promoting rational use of fertiliser and pesticide
- achieving zero-growth or use reduction goals for agrochemicals
- processing livestock waste into organic fertiliser
- upgrading legal framework for arable land protection including upgrades to
- land ownership and use rights
- soil environmental protection and pollution
- soil related legal frameworks lag far behind those for air, water
- improving technical support for soil remediation
- identifying and studying sources of pollution
- developing restoration and pollution management technology
- setting up a special science and technology plan for soil