中国饲料粮进口的产品替代性与市场竞争关系

Product Substitution and Market Competition of China’s Feed Grain Imports: The Rotterdam Model versus AIDS

在饲料粮进口呈现产品多样化、来源多元化格局下,对中国饲料粮进口的产品替代性和市场竞争关系进行研究,可以准确把握饲料粮进口市场格局及供给效率状况。利用2010—2019年月度进口贸易数据,基于Cox检验确定了适用的区分来源进口需求系统,利用模型估计结果测算了区分进口来源的多种饲料粮的支出弹性、马歇尔价格弹性和剔除收入效应的希克斯价格弹性。创新之处在于,将4种关联的饲料粮产品纳入同一进口需求系统,并对进口来源加以区分;将Cox检验应用于甄别更适用的进口需求模型系统,有效降低模型选择不当造成的结果偏误。研究发现,饲料粮的进口来源集中,玉米和高粱的主要来源国之间呈现一定的竞争关系;大麦主要来源国之间的竞争性不强,中国对进口大麦具有稳定的需求和来源地,对主要来源国有较强的依赖性;未来饲料粮需求的满足将更多依靠进口,对美国市场的依赖将进一步加深;进口玉米、大麦和高粱相互之间呈现较强的替代性,DDGS与玉米、大麦、高粱之间存在互补关系。

With diversified products and diversified origins of China’s feed grain imports, this paper analyzed the imported product substitutions and market competitions to accurately grasp the feed grain import market pattern and supply efficiency.Using monthly import data from 2010 to 2019,we selected the applicable source-differentiated import demand system based on the Cox test.The estimation results are then used to measure the expenditure elasticity, Marshall price elasticity and Hicks price elasticity that excluded income effects of several kinds of feed grains from different import origins.There are two innovations in this paper.First, four related feed grains were incorporated into one import demand system and the import origin countries were differentiated.Second, the Cox test was adopted to identify more suitable import demand model, which could effectively reduce the result bias caused by model selection.The results first show that the import origins of feed grains are concentrated, and the main origin countries of corn and sorghum present a competition relationship in a certain degree.Second, the competition among the main origin countries of barley is not strong, which means that China has stable demand for imported barley and stable import sources, and has strong dependence on the main origin countries.Third, the satisfaction of feed grain demand will rely more on imports in the future, and the dependence on the U.S.market will be further deepened.Fourth, imported corn, barley and sorghum show strong substitutes among each other, and DDGS shows a complementary relationship to corn, barley and sorghum.