Degradable plastic materials made from biopolymer Chitosan (CS) present one of the alternatives to plastic bags for food packaging, but the stability and durability limits its application. Herein, we demonstrated a facile method of producing hydrophobic CS/salicylic acid (SA) film in organic phase for the first time. SA, which can destruct hydrogen bonds of CS was initially blended with CS in N, N-dimethylacetamide using a catalyst. On this basis, CS/SA blend was crosslinked via isocyanate to the hydrophobic CS-SA film. The derivatives structures were characterized using SEM, FTIR, UV-Vis, and fluorescence spectrum. The film-forming ability of CS was maintained, while the hydrophobicity, mechanical strength, and thermal stability of films were improved.These dramatic improvements occurred with the blending effects of CS and SA and the crosslinking effects of organic isocyanate cross linker. The permeabilities to water vapor and water-soluble substances of film were promoted, which are conducive to the application of the film as food packaging. The demonstration of bacteriostatic and grape preservation properties featured the super performance of the synthetic CS/SA film. Our work provides novel food preservation materials, which can replace the commonly used packaging materials and promote the development of the degradable food packaging plastic bags field.

Context Rapid desalination by planting rice in saline soil consumes large amounts of water, which is not environmentally friendly. Aims Herein, we propose rapid desalination by planting rice, then shifting to cultivating upland plants to attain substantial resource-saving and higher yield simultaneously with restoration of saline-sodic soil. Methods Field experiments were run for two consecutive years with five treatments: unreclaimed wasteland (WL) as control, rice cultivation followed by fallow (RF), rice–rice continuous cropping (RR), rice–ryegrass rotation (RG), and rice–sorghum rotation (RS). Physicochemical properties, including pH, electrical conductivity, and exchangeable sodium percentage were determined, and 16S rRNA sequences were used to evaluate soil microbial composition and stability. Key results The soil total organic carbon, total nitrogen, available phosphorus, and biomass in RR, RG, and RS treatments were all higher than RF and control. Notably, RR, RG, and RS increased the soil microbial biomass carbon and nitrogen, and significantly reshaped the soil communities of bacteria, fungi, and archaea relative to RF and WL. Conclusions Despite the lower efficiency of RG and RS in ameliorating saline-sodic soil, there were dramatic savings in irrigation water, and the improvements in microbial diversity and functionalities indicated that the paddy–upland crop rotation system had substantial influence on sustainability of soil quality. Implications Providing a balance between salt desalination performance with irrigation water input and yield, the paddy–upland rotation system is a robust, replicable, and environmentally friendly practice in saline-sodic soil remediation.