新疆农田残膜污染现状及防控策略

塑料污染是全球性的难点问题,残膜污染是塑料污染在农田的表现形式。新疆是中国重要的农产品生产基地,覆膜种植总面积达347.8万hm2,年地膜投入量超过20万t,是全国残膜污染最为严重区域,具有代表性。总结新疆农田残膜污染的特点、综合治理现状以及存在问题对全国农田残膜污染的治理有较大的借鉴作用。该文应用文献检索归纳、信息查阅以及田野调查等研究方法,对新疆农田残膜残留区域分布特点与残膜在土壤中的空间分布特点进行了总结归纳;分析了地膜投入成本、地膜力学性能以及回收因素等残膜产生成因;对近年来农田残膜污染综合治理技术进行了梳理,总结了农艺防治、可降解地膜、多种回收组合模式以及机械化回收等4大类综合治理技术。最后,探讨了目前残膜污染综合治理中存在的农机农艺融合综合治理、残膜机械化回收、系统性农艺措施以及监测评价等问题,分析了完善残膜污染治理法规、把握农机-农艺-农膜相结合理念、加大耕层残膜的分级治理、研究新型地膜技术以及创新地膜应用栽培模式等污染防控策略。研究表明:现阶段PE地膜仍是农业生产的主要应用方式,开发新型地膜与可降解地膜,实现PE地膜的完全替代是未来的研究目标;新疆农田残膜污染治理应坚持"遏制增量,减少存量"的方针,加大地膜的机械化回收,规范农用地膜的使用与回收再利用,优化种植模式,建立残膜污染治理的可循环模式,以期对典型区农田残膜污染综合治理提供借鉴参考与解决思路。

Current situation and control strategies of residual film pollution in Xinjiang

Abstract: Plastic pollution has become a global environmental concern and residual plastic films resulted from agricultural production played a significant part in it. Xinjiang in China is a region of 160 million hectares and its agricultural production is mainly in the proximal areas of the Taklamakan desert - the second largest desert in the world. Rainfall in Xinjiang is scanty but sunshine is abundant. For reducing evaporation, therefore, approximately 3.478 million hm2 of croplands in Xinjiang is mulched annually by over 200,000 tons of plastic films, making Xinjiang the most contaminated region by residual plastic films in China. In this paper, we analyzed the distribution of residual plastic films in croplands in Xinjiang based on literature review, consulting and field surveys. The results showed that the residual plastic films in soil were found mainly in three layers: soil surface, 0-12 cm and 12-30 cm layers, among which 6%-8.33% was on the soil surface, 53.99%-68% in 0-12 cm layer and 26%-37.68% in 12-30 cm layer. We also analyzed the reasons behind residual film pollution, including costs of the mulch film, its mechanical properties and factors affecting its recovery. Comprehensive technologies for alleviating residual film pollution in Xinjiang were evaluated, which include improving agronomic control, using degradable films and improving film recycling. We also discussed the difficulties faced by implementation of these technologies, especially in integrating agricultural machinery and agronomical technology, mechanical recovery of the films, and systems to monitor and evaluate the residual film pollution. To ameliorate the film contamination, legal regulation for improving treatment of residual film pollution should be mandatory and new technique of integrating agricultural machinery-agronomy-agricultural film should be developed. In addition to these, methods such as boosting residual film degradation in soil, developing new plastic film, and innovating strategies to prevent and control residual film pollution, should be sought. Currently, PE mulch is still the main application in agricultural production and future research should focus on developing new degradable mulch to replace the PE mulch. In summary, mitigating residual film pollution in croplands in Xinjiang should follow 1) "restraining the increase in film production, and reducing the film stock", 2) increasing mechanical recovery, standardizing film, optimizing cropping systems, and establishing recycling systems.