As the COVID-19 epidemic swept the world in early 2020, it is worth watching how it affects the total factor productivity of enterprises. Based on the theory of information asymmetry and the data of A-share listed companies from 2014 to 2021, this paper conducts an empirical study on the relationship between COVID-19 and the total factor productivity of enterprises. The results show that the impact of the COVID-19 epidemic can significantly reduce the total factor productivity of enterprises, and the conclusion is still true after a series of robustness tests. Taking the financing constraint as an intervening variable, it clearly reveals a transmission mechanism, that is to say, the impact of the COVID-19 epidemic exacerbates the financing constraint of the enterprise, thus it makes the total factor productivity of the enterprise reduce. It is further found that the above effects are more obvious for small and medium-sized enterprises and non-intelligent enterprises. Based on this, the government should implement some active economic development policies to create a free, relaxed and orderly market environment for enterprise financing. At the same time, enterprises should not only pay attention to digital and intelligent development, and transform into technology-intensive enterprises, but also strengthen the awareness of worry. Enterprises should store "more grain" for preparing for the cold winter.

The COVID-19 pandemic wreaked havoc on economies everywhere, affecting everything from supply chain networks to international trade as a direct result of the increased vulnerability of more nations and the disruption of the activities of key traders. This research study examines how COVID-19 affected the supply chain on a worldwide and regional scale, as well as the systemic policy and economic steps governments and businesses took to rebound and maintain resilience. COVID-19 has had a significant influence, prompting governments and businesses to take steps to fortify their operations and businesses against disruptions, highlight the necessity for resilience in supply chains and emphasize the importance of managing risk. The supply value chain is at risk from the prolonged implementation of COVID-19 trade measures like border closure, export restrictions, and import sanctions. Many businesses are transitioning from a "recovery mode" to a resilient and sustainable mode" and are beginning to plan for the future. The study suggests that corporate and government leaders should prioritize proactive and adaptable policy, economic, and structural adjustment. This research will be useful to policymakers and industry leaders in their efforts to lessen the effect of COVID-19 on the global supply chain by enforcing governmental, economic, and business reforms built on resilient supply chains and mitigating economic risks during tough times.

Grain trade plays a critical role in global grain security and the balance of grain supply and demand across countries. As globalization progresses, the complexity and diversity of grain trade have become increasingly prominent. Its significance extends beyond the economic sphere, directly impacting social stability and international relations. The dynamic development of grain trade is influenced by a variety of factors, including climate change, international economic policies, technological advancements, and geopolitics. At the same time, the complexity of global grain supply chains, the uncertainty of international trade policies, and the frequent occurrence of extreme climate events pose significant challenges to the smooth operation of grain trade. In recent years, there has been growing attention in the international community on how to achieve the sustainable development of grain trade by optimizing policies, strengthening international cooperation, and promoting technological innovation. This study systematically reviews the existing literature on grain trade, providing a comprehensive summary of the research landscape, covering factors influencing grain trade, development trends, supply chain management, and risk management. The goal is to provide a systematic analysis and insights for both academics and policymakers, as well as directions and references for future research. Additionally, the study explores how grain trade has maintained resilience amid global crises such as the COVID-19 pandemic and climate change, and offers strategic recommendations for achieving global grain security. This research aims to further promote the sustainable development of grain trade systems and provide strong support for global grain security and socioeconomic stability.