地膜覆盖对蔬菜生产和农田环境的影响

Effects of Plastic Film Mulching on Vegetable Production and Farmland Environment

传统聚乙烯地膜覆盖具有保温、保墒、除草等功能,在蔬菜生产中发挥了重要作用,然而随着地膜覆盖技术的推广及未对使用后地膜进行有效回收,土壤中地膜残留量逐年增加,带来的负面影响越来越明显。传统聚乙烯地膜残留在土壤中会阻断土壤毛管,截断水、气运移和交换通道,改变土壤孔隙度,破坏土壤结构;在蔬菜根系附近会产生包裹、阻碍等效应,抑制根系生长,进而降低植株地上部生长和叶片代谢水平,最终造成产量下降,制约了蔬菜的可持续生产;同时土壤中的残膜随耕作与时间推移老化裂解为微/纳米塑料,进入植株和动物体内,对人类的身体健康产生潜在威胁。在自然条件下可以被微生物分解成二氧化碳和水的生物降解地膜有效缓解了这一危机,既具备增温保墒等功能,又能够促进作物生长,有效缓解白色污染,具有巨大的应用前景;但由于技术尚不成熟,降解性能受环境条件的影响比较大,降解速率难以控制,且成本较高难以推广,仍面临许多挑战。

Traditional polyethylene film mulching has the functions of heat preservation,moisture conservation and weeding,and plays an important role in vegetable production.However,with the promotion of plastic film mulching technology and the lack of effective recovery of plastic film after use,the residual amount of plastic film in soil is increasing year by year,and the negative impact is becoming more and more obvious.The residue of traditional polyethylene mulch film in soil will block soil capillary,cut off water and gas migration and exchange channels,change soil porosity and destroy soil structure.In the vicinity of the vegetable root system,there will be effects such as encapsulation and obstruction,which will inhibit the growth of the root system,and then reduce the growth of the above-ground part of the plant and the metabolic level of the leaves,resulting in a decrease in yield and restricting the sustainable production of vegetables.At the same time,the residual film in the soil is aged and cracked into micro/nanoplastics with tillage and time,which enters plants and animals and poses a potential threat to human health.Biodegradable mulch film,which can be decomposed into carbon dioxide and water by microorganisms under natural conditions,effectively alleviates this crisis.It not only has the functions of increasing temperature and preserving soil moisture,but also can promote crop growth and effectively alleviate white pollution,which has great application prospects.However,due to the immature technology,the degradation performance is greatly affected by environmental conditions,the degradation rate is difficult to control,and the cost is high.It is difficult to promote and still faces many challenges.