ass日本风韵熟妇pics男人扒开女人屁屁桶到爽|扒开胸露出奶头亲吻视频|邻居少妇的诱惑|人人妻在线播放|日日摸夜夜摸狠狠摸婷婷|制服 丝袜 人妻|激情熟妇中文字幕|看黄色欧美特一级|日本av人妻系列|高潮对白av,丰满岳妇乱熟妇之荡,日本丰满熟妇乱又伦,日韩欧美一区二区三区在线

Plastic film mulching cultivation has been widely used in agricultural production due to the benefits such as increasing soil temperature, reducing weed pressure and certain insect pest and improving crop yields. The plastic film mulching area in China is more than 20 million hm2 and this technology provides significant support for the crop yield improvement and food security. Residual plastic film in soil is increased in quantity with the increase of mulching duration and area, and the residual plastic film pollution had seriously threatened agricultural production and natural environment, which has become a prominent problem affecting the sustainable development of agricultural production in China. The technology and equipment of residual plastic film at home and abroad was reviewed, the representative model and structure of residual plastic film collecting machine which used in different periods, including pre-sowing stage, seeding stage and autumn film collection stage were summarized in detail, and their merits and demerits were analyzed. Then the foreign policies and regulations on the collection and management of agricultural plastic film and domestic policies for residual plastic film pollution control were systematically summarized. Finally, the current research feature in this field was summarized and future development direction was shown clearly based on policy, technology and demand of agricultural sustainable development. Corresponding technology and scheme of residual plastic film control for China’s national conditions were proposed as following: replacing ordinary nondegradable film with degradable film; guaranteeing the mechanized collection of ordinary plastic film, especially establishing the completely mechanized collection system for residual plastic film; opening up the new channel for reusing residual plastic film. In conclusion, development of the residual plastic film collecting machine with good quality and high reliability is important guarantees to control residual plastic film pollution, and research on innovative reuse technology of residual film is an inevitable trend.