Aquo-bioplastic from rotten bamboo-derived carboxymethyl cellulose for biodegradable mulching

Plastic mulching has been widely utilized to enhance crop yield but generates persistent plastic residues that threaten agricultural sustainability. To address this challenge, a biodegradable and sprayable liquid mulching of carboxymethyl cellulose (CMC)-based 'aquo-bioplastic' derived from renewable rotten bamboo was developed. Natural deconstruction remodeled the bamboo cell walls, enhancing cellulose accessibility by providing cellulose with lower crystallinity, less degree of polymerization, and more exposed reactive hydroxyl groups for efficient etherification into CMC, and subsequent crosslinking with glutaraldehyde for aquo-bioplastic. The resulting aquo-bioplastic exhibited strong mechanical properties (75.5 MPa of tensile strength and 527.6 MPa of Young's modulus) and excellent air resistance (0.003 μm/Pa·s) exceeding reported bio-plastic films. Furthermore, the aquo-bioplastic was facilely applied in the field by drone spraying, enabling automated mulching and promoting soil moisture, temperature, seed germination, and eventually crop growth. Following field application, the aquo-bioplastic has been completely biodegraded within 64 days in soil, eliminating the requirement for post-harvest mulch removal. These results collectively suggest that CMC-based aquo-bioplastic derived from rotten bamboo could serve as an alternative of traditional plastic mulch to tackle white pollution and promote sustainable agriculture.