Based on the trade data from 2000 to 2019, this paper uses a complex network analysis method to evaluate the dynamics of global pork trade networks and to identify the characteristics of China's pork networks. Moreover, the issue of potential trade partners for China to expand its pork imports in the future has been discussed. The results show that, while the trade links between the countries involved in global pork trade are relatively "scattered" during the past two decades, the core players in the global pork trade networks are relatively fixed. China, as the No.1 pork importing country in the world, has been playing an increasingly important role in the global pork trade networks. As China's pork imports volume grows, North America, Western Europe and South America have been turning into China's main source of imports, and showing a "tripartite" source pattern. To expand its pork imports in the future, China could have a wide range of potential pork trading partners judging from the current global trade networks. On the one hand, China could deepen the trade relations with its traditional pork trade partners, i.e., Germany, Spain, the USA and Brazil. On the other hand, China could seek for new trade partners, for example, expanding pork imports from Italy and Belgium, as well as other neighboring countries such as Thailand and Vietnam.

Based on the complex network analysis, this paper constructs the global grain trade network of wheat, rice and corn. The study analyzes the overall characteristics and changing trends of the network pattern, and quantitatively evaluates the influencing factors of the network pattern of global grain trade. The result shows that: Firstly, the global food trade network has become a complex, orderly and interdependent network system. The network scale is increasing, and the degree of connectivity and tightness are strengthening continuously. Secondly, the nodes of the global food trade network show the characteristics of disequilibrium structure. And countries with high strength and high node degree play a leading role in the network, showing the characteristics of network structure dominated by exporting countries. Thirdly, economic and social differences, consistency of trade policies, linguistic and cultural proximity have significant effects on food trade networks. Economic and social differences have driven trade networks to become more interconnected and diversified. Consistency in trade policy contributes to a more sustainable and robust trade network. Therefore, it is suggested that China implement a more diversified and multilateralized grain trade policy. China should strengthen and enhance its centrality among nodes of the global food network, fully integrate into the global food trade network, and promote the building of a global community of shared future for food security.

International food trade is an important factor affecting food security and environmental sustainability. Soybeans are an important food trade commodity, and the import amount of soybeans has been dramatically affected by the international situation. Since China has become the largest soybean importer, quantitative analysis of the impacts of soybean imports in China on global environment is of great significance, which helps us understand food security and global sustainability, and this is particularly true in the context of China-United States trade disputes. To obtain the soybean import volumes of China from its major suppliers (the United States, Brazil, Argentina, Uruguay, and Canada), we first adopted the GTAP (Global Trade Analysis Project) model and its database, and built four soybean tariff scenarios. Then, we calculated the amount of water and farmland used per ton of soybeans produced in each country, and studied the amount of total virtual water and virtual farmland produced in the four scenarios. The results show that the total imported soybeans and total virtual farmland remained stable, while the total virtual water varied considerably among four scenarios. The total soybean imports, virtual water, and virtual farmland from each supplier varied greatly, and the United States experienced the strongest decrease. Soybean produced in Brazil consumed the least water, while the United States consumed the least arable land. Soybean import of China could improve water and farmland resource efficiency, relieve environmental pressure, and enhance food security.

The paper uses the literature data, spatial analysis and grey correlation analysis to examine the spatial distribution and influencing factors of China's overseas farmland investment activities in Southeast Asia. The results show that: (1) China's overseas farmland investment projects are mostly distributed in the Indo-China Peninsula along the border of China. (2) The spatial distribution of China's overseas farmland investment intention projects and contract projects in this region is similar, while that of the production projects is different from the other two types of projects. (3) China's overseas farmland investment is affected by geo-economy, geo-culture, resource conditions, and geo-politics, and the degree of impact decreases in succession. Indicators such as the average annual total import and export value and the average annual stock of China's foreign direct investment have a significant impact on the choices of Chinese investment companies. Southeast Asia is an important area for China's overseas farmland investment, therefore strengthening economic and cultural exchanges with Southeast Asian countries will play an important role in promoting the smooth development of overseas farmland investment activities carried out by Chinese companies.

Trade liberalization and regional economic integration will not only lead to market integration and efficiency improvement through comparative advantages, but also produce transaction of "virtual resources", such as "virtual water" and "virtual land". Based on the time series model, and the food trade and prices data covering China and Pakistan, this paper first examines the degree of food market integration of the two countries. Secondly, we calculate the net flow of virtual water and virtual land resources accompanied by the rice trade, and analyze changes in resource efficiency. The results showed that: (1) The rice market between China and Pakistan has been highly integrated, but the price of rice in Pakistan is more fluctuant than that in China, and the price elasticity of rice in Pakistan is 1.097 with respect to that of China. This means that if rice price in China increases by 10%, the one in Pakistan will increase by 10.97%. Since the launch of the Belt and Road Initiative, rice price in Pakistan has fallen by 7.8%, which increases the welfare of the poor. (2) After 1988, China had net imports of 3.54 million tons of rice from Pakistan in total, equivalent to 520000 hectares of domestic cultivated land, or 964000 hectares of agricultural land in Pakistan, 3.44 billion tons of domestic water or 10.17 billion tons of water in Pakistan. The empirical results indicate a great difference in the utilization efficiency of land and water resources between China and Pakistan. Although the utilization efficiency of nature resources has been converging after the implementation of the B&R Initiative and the China-Pakistan Economic Corridor Project, the converging speed is not high enough. China should continue to promote the technology spillover to Pakistan and other B&R Initiative countries, help them overcome difficulties in raising low resources utilization efficiency, and increase the yield of rice to finally achieve the convergence of resource utilization efficiency. In global viewpoint, this not only ensures food security, but also saves natural resources, which is in line with the core goal of B&R Initiative: to make full use of comparative advantages in cooperating countries, to achieve free flow of factors and win-win cooperation, and finally build a community with a shared future, interests and responsibilities for mankind.