Food security is the foundation of a nation, with its core being the guarantee of food production security. The intensification of global climate change, the frequent occurrence of extreme weather and climate events, coupled with the uncertainty of the external environment, pose severe challenges to China's food production. The technology of agricultural land film mulching is of vital importance to ensuring food security. Currently, the global demand for food is continuously increasing. To prevent and control the risk of microplastic pollution caused by residual agricultural film, this study aimed to clarify the substitution potential of straw fiber-based fully biodegradable mulch films in crop mulching cultivation. The research developed two new types of mulching materials using straw as raw material: nitrogen slow-release coated straw fiber mulch film (NSFM) and lignin-coated straw fiber mulch film (LSFM). A facility garlic cultivation experiment was conducted with traditional PBAT/PLA mulch film and no mulch (CK) as control groups. Using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy, the microstructure and morphological evolution of the mulch films during degradation were characterized. The study systematically analyzed their effects on the absorption of medium and trace elements, quality, and yield components of garlic plants, and comprehensively evaluated their economic benefits. The results showed that LSFM, NSFM, and PBAT/PLA mulch films all exhibited good degradability. Within 0-100 days of mulching, the degradation rate of LSFM was higher than that of NSFM and PBAT/PLA; from 100 to 120 days, the degradation rate of PBAT/PLA was significantly higher than that of NSFM, but there was no significant difference compared with LSFM, indicating that NSFM had better field durability. In terms of improving garlic quality, both NSFM and LSFM significantly promoted the absorption and accumulation of medium and trace elements such as Fe, Zn, and Se in plants. Among them, the Se content in garlic under NSFM mulching was 51.85% higher than that under PBAT/PLA mulching; both new mulch films significantly increased the alliin content in garlic sprouts, with better effects than PBAT/PLA and CK, and NSFM could significantly enhance the antioxidant capacity of garlic. In terms of yield, there was no significant difference between NSFM and PBAT/PLA treatments, but NSFM was superior in dry matter accumulation efficiency. Overall, NSFM can stably maintain garlic yield and significantly improve its nutritional quality and antioxidant activity. This mulch film, made from agricultural waste, has better degradation controllability and field applicability. It is a feasible technical path to realize the green substitution of traditional PBAT/PLA mulch films and promote low-carbon agricultural production. The straw fiber-based biodegradable film is a green, low-carbon and multi-functional new material, which combines environmental sustainability with production practicability. It has broad application prospects in the future green development of agriculture.

Rice straw is an important renewable resource. Under the circumstance of global resource shortage and energy shortage, it is of great significance to vigorously develop comprehensive utilization of straw. It is not only an important way to realize agricultural circular economy and low-carbon economy, but also involves sustainable development issues such as soil fertility, environmental security and efficient utilization of renewable resources in the entire agricultural ecosystem. Straw fiber ecological blanket has a good function of air permeability and water permeability, and has a significant positive effect on the ecological protection of soil surface microenvironment. Mechanical kneading is the key technology for the dismantling and optimization of agricultural waste straw fiber. In this study, the optimal process input is the spindle speed, hammer tooth clearance and material water content, and the output is the straw silk rate and calibrated unit productivity. An intelligent model was developed using Box-Behnken response surface method (RSM) to determine the functional relationship between input and output parameters. The three evaluation index models all have high reliability, and the determination coefficients are R² > 0.95 and R² > 0.84, respectively. The variance analysis of RSM regression model clarified that the influence of various factors on straw silk ratio was in the order of spindle speed > water content > hammer tooth clearance, and the linear relationship between spindle speed and straw silk ratio was increasing. The significant influence on the calibrated unit power productivity of the kneading machine is in the order of hammer tooth clearance > spindle speed > moisture content. When the hammer tooth clearance is constant, it decreases first and then increases with the spindle speed and straw moisture content. The results of factor interaction analysis showed that when the water content of straw was 40%, the spindle speed was 2 500 r/min, and the hammer tooth clearance was 13 mm, the silk ratio of rice straw was 96.75%. When the straw moisture content is 60%, the spindle speed is 2 300 r/min, and the hammer tooth clearance is 11.08 mm, the maximum calibrated unit power productivity is 29.96 kg/(kW·h). Mathematical model process parameters optimization: straw moisture content is 41.2%, spindle speed is 2498 r/min, hammer tooth clearance is 12.84 mm. Under the combination of these parameters, the rice straw silk ratio is 96.93%, and the calibrated unit power productivity is 29.33 kg/(kW·h). Under optimized conditions, the proportion of fibers with length of 40-70 mm and > 70 mm showed an increasing trend, especially the fiber with length of > 70 mm increased by 120.55%. The proportion of fiber length-to-width ratio > 50-80 and > 80 increased from 17.39% and 6.52% to 38.64% and 16.01%, respectively. Ultra depth of field microscopy showed that the self-interweaving formability of kneaded straw fiber was significantly improved. The optimized mechanical kneading cost of straw fiber can be reduced by 27.50 yuan/t. The mechanical kneading technology strategy of the RSM model developed in this paper is effective for improving the decomposition rate of biomass straw and reducing the consumption of biomass straw, and can be widely used in the production of high-value agricultural products based on large fiber bundles of straw. The mechanical kneading technique strategy of the RSM model developed in this paper is effective for improving the decomposing silk rate and reducing the consumption of biomass straw, and can be widely used in the production of large-size fiber bundle straw based high-value agricultural products.