残膜污染防治与可降解地膜生态环境影响评价

Control of Residual Film Pollution and Ecological Environment Impact Assessment of Degradable Mulch Film

地膜作为重要的农业生产资料,在我国使用量十分巨大。2014年全国地膜使用量达到144万吨,比1992年增长了近3倍,年均增长率约为6%;新疆、山东和甘肃三地的地膜覆盖面积占到全国覆盖面积的38%。但传统透明塑料地膜性能稳定,不易降解,大量残留在耕地中,部分地区残膜量远高于我国75.0kg/hm2的残留限值,表现出积累效应明显、污染区域差异大、污染强度逐年增大的特征。可降解地膜是降低残膜对农田环境污染的有效手段,本研究考虑可降解地膜迁移、转化、归趋过程,利用残膜率、未出苗率、蚯蚓死亡率和重金属污染度指标,建立可降解地膜生态环境影响评价模型,并将可降解地膜对生态环境的影响分为无影响、影响较小、中等影响和影响较大四级,为评价可降解地膜生态环境影响提供了一种研究思路。

As an important agricultural production materials,plastic film has a huge use in China. The usage amount of mulch film in 2014 reached to 1. 44 million tons,which increased by three times than that in1992 with the annual growth rate of about 6%. The sum covered area of three provinces of Xinjiang,Shandong and Gansu occupied 38% of the total covered area in China. The traditional transparent plastic film is not easy to degrade after using because of its stable properties. The residual film quantity in farmland in some area is much higher than the limit value of 75. 0 kg / hm2 in China. The residual film pollution shows the characteristics of obvious accumulative effect,large difference in different pollution areas and annual increasing pollution intensity. Degradable mulch film is an effective way to prevent the residual film pollution. Considering the migration,transformation and fate processes of degradable plastic film,the ecological environment impact assessment model was established with rate of residual film,seedling non-emergence rate,earthworm mortality and heavy metal pollution level as indices. The model assessed and divided the ecological environment impact of degradable plastic film into four levels of no impact,small impact,medium impact and large impact. This study provided a research method for evaluating the ecological environment impact of degradable mulch film.