地膜对农业生产的影响及其污染控制

地膜覆盖具有显著的农业生产效益,可以增温保墒,防虫抑草,扩大作物种植适宜区,从而提高农作物产量和品质,因此在世界范围内尤其是在干旱半干旱地区农田中得到广泛应用。然而,塑料地膜降解速率极其缓慢,加上中国地膜回收工作的开展较为落后,导致大量的塑料碎片残留在农田中,从而造成土壤环境的残膜及微塑料污染。本文基于文献资料、调研和统计数据,就地膜对中国农业生产的影响及其污染防控进行了分析。残膜及微塑料污染会改变土壤理化性质,限制土壤水分和养分运移,并对土壤动植物的生长、发育和繁殖产生危害,改变土壤微生物的丰度和群落结构,损害土壤健康,长此以往会造成作物产量和品质下降,甚至威胁到粮食安全。微塑料存在被植物吸收的可能性,从而通过食物链进入人体,对人体健康产生威胁。此外,微塑料巨大的比表面积使其极容易通过吸附作用成为其他污染物（重金属、农药和抗生素等）的载体,增加污染物的转移富集风险,从而造成土壤生态环境复合污染。中国地膜生产、使用相关标准正在逐步完善,但同发达国家和地区相比仍有一定的差距。中国尚未形成完善可持续的地膜回收体系,农田土壤中的微塑料污染研究仍不够充分,同时针对残膜及微塑料污染防控的政策和法规也有待于进一步完善。因此应进一步借鉴发达国家和地区的经验,结合中国实际情况,因地制宜制定地膜生产、回收相关标准以及残膜和微塑料污染防治的政策法规。

Influence of Plastic Film on Agricultural Production and Its Pollution Control

Plastic film has been widely used in the farmland all over the world especially in arid and semi-arid areas because of its remarkable agricultural benefits, such as increasing soil temperature and moisture, reducing weed and pest damage, extending crop-growing areas, and consequently improving crop yield and quality. However, the degradation rate of plastic film is extremely slow, and the recovery of plastic film is also relatively backward in China, which lead to a large number of plastic debris in the farmland, causing plastic residues and microplastics pollution in the soil environment. Based on literature, investigation and statistical data, this research reviewed and prospects the impact of plastic film on agricultural production and pollution control in China. Plastic residues and microplastics have been reported to change the physical and chemical properties of soil, restrict soil water and nutrient transport, do harm to the growth, development and reproduction of soil animals and plants, change the abundance and community structure of soil microorganisms, and damage the soil health. In the long-term, plastic residues and microplastics pollution will cause a decline in crop yield and quality. Microplastics had the potential to be absorbed by plants, enter the human body through the food chain and pose a threat to human health. In addition, the large specific surface area of microplastics enabled them to become carriers of other pollutants (e.g. heavy metals, pesticides and antibiotics), causing combined pollution to the soil ecological environment. The standard of plastic film production and use in China was gradually being improved, however, there was still a certain gap compared with developed countries and regions. In addition, a sustainable recycling system of plastic film and the policy of preventing plastic residue and microplastics pollution have not been well formed in China, and the study of microplastics pollution in Chinese farmland soil was still very limited. Therefore, it is critical to solve the problem of plastic residues and microplastics pollution in the soil by evaluating the present situation of plastic residues and microplastics pollution in soils, quantifying the effects of microplastics on the soil environment, and evaluating risks of microplastics to the soil ecosystems, as well as exploring the measures of controlling soil plastic residues and microplastics pollution, and formulating relevant policies and regulations of preventing these pollution.