Development and prospect of biodegradable mulch films in China

China has the largest usage of plastic mulch films in the world, reaching 20 million ha and 1.4 million t year^‑1. Wide utilization of film mulching technology largely contributed to the dramatic increase of agricultural production and change of production pattern. However, more and more film residues accumulated in field led to serious “white pollution” that threatens sustainable agricultural development. Investigation and application of biodegradable mulch films shed important light to overcome film residue contamination. For systematic evaluation and optimization of biodegradable mulch films, large scale field experiments were carried out in 11 provinces with different type biodegradable mulch film provided by 21 enterprises in China on growth of maize, cotton, potato, peanut, vegetable and tobacco, respectively since 2011. Ultimate tensile properties, functional properties (warm and moisture conservation), biodegradability, and economical efficiency of different biodegradable mulch films, in association with safety mulching period of different crops, under distinct environments were evaluated extensively. Formulations and process operations of biodegradable mulch films were being repetitiously optimized accordingly. Through our great effort, biodegradable mulch films from corresponding industries have been greatly improved, especially in terms of mechanical and functional properties, that generally satisfied crop growing request. Though high cost and pre-degradation are still core problems prohibiting wide application. In this study, we systematically reviewed the developing history of biodegradable mulch film in China, deeply discussed its present situation and limitation, and finally enclosed with prospect and challenge of the biodegradable film application in China.