Pollution Status and Control Countermeasures of Polyethylene Mulch Film Residue in Farmland Soils of Qingdao City, China

Qingdao City, China LI Yan-chao1, LI Hai-ping2, WANG Yong-xian2, SUN Ya-ping2, WANG Kai-rong1*, YANG Qing-xian3 (1.College of Resources and Environment, Qingdao Engineering Research Center for Rural Environment, Qingdao Agricultural University, Qingdao 266109, China; 2.Qingdao Agricultural Environmental Protection and Rural Energy Extension Station, Qingdao 266071, China; 3.Jimo Agricultural Bureau,Jimo 266200,China) Abstract:The benefits of using polyethylene(PE)mulch films in agriculture are well established in China. However, residues of PE films contaminate soils. Disposing of used films may lead to off -site environmental pollution, especially contributing to white pollution. We conducted a study to measure the amount of PE film residue in a number of farmland soils(27 sites)previously subjected to long-term film mulching across five main agriculture production regions of Qingdao, China. The amount of film residue in soils was highly variable with the mean being 32.3依15.7 kg·hm-2. Seven sites exceeded 40 kg·hm-2 with the highest being 69.3 kg·hm-2. There was no evident correlation between the amount of film residue in soil and the type of cropping system or the number of years of surface mulching, but was related to the recovery rate of the film in the current season. About 1.6% of the recovered PE films was in pieces less than 2 cm2, 7.3% was between 2 cm2 and 20 cm2, 19.2% was between 20 cm2 and 100 cm2, and the remainder(71.9%)was in pieces greater than 100 cm2. More than 90% of the residue PE films was in the 0~20 cm ploughing soil layer, while 5% was in the 20~30 cm layer. A number of key steps are suggested to control the ongoing pollution of PE film residue in farmland:(1)Establish and implement a comprehensive program for controlling soil PE film 农 业 资 源与 环 境 学 报 2017年 5月·第 34卷·第 3期:226-233 May 2017·Vol.34·No.3:226-233 Journal of Agricultural Resources and Environment