Preparation, properties and field application of biodegradable and phosphorus-release films based on fermentation residue

Abstract Mulch films are used in agricultural application mainly to produce high-quality crops. Based on Penicillium chrysogenum mycelium or on citric acid fermentation residue, biodegradable films with the function of soil temperature preservation, moisture maintenance and controlled fertilizer release of P were manufactured in this work to avoid waste of bioresources and plastic film pollution. They had been later used as suitable alternative to low density polyethylene (LDPE) films for cotton and maize production. Mechanical properties, water vapor permeability and thermal tests of films were measured in the laboratory before application. Their weight loss, microorganism growth on their surface and soil microclimate were also investigated during field application to evaluate their biodegradability. Only small cracks emerged in the structure of biodegradable films after four weeks in contact with the soil. The loss weight of the two films could reach about 40% and 21%, respectively after 90 days of application. The study also showed that biodegradable films demonstrated soil temperature preservation with 5–7 °C higher than un-mulched control and comparable function of moisture maintenance with commercial films after application.