The off-field utilization of crop straw requires a highly efficient collection, storage, and transportation system, focusing on the synergistic optimization of efficiency, cost, and carbon emissions. Four typical scenarios are selected to identify co-benefits in the town scaled straw transfer site: all-manual collection (I), 50% manual collection (II), small-scale machinery collection (III), and large-scale machinery collection (IV). The results indicate that, while achieving collection efficiency within 30 days, the scenario I exhibited the highest collection costs (460.9 CNY/ton) and carbon emissions (65.4 kg CO2/ton). In contrast, Scenario II, III, and IV achieved reduction in collection costs by 34.4%, 54.1%, and 60.3%, respectively, while carbon emissions reducing by 25.3%, 55.2%, and 65.9%. The transportation process would play an important role in cost reduction, wherein baled straws could lead to an average reduction in transportation costs of 66.1%. The pretreatment processing in straw transfer site is the determined factor to decline the carbon emissions, with the Scenario I and II accounting for an average of 59.2% of the total emissions. According to the analysis, further improving mechanization level in straw collection, storage, and transportation process, optimization of transportation tools and strategies, and equipment performance improvement could be a viable pathway to achieve the synergistic optimization of efficiency, cost, and carbon emissions.
