【作者】 王茂丽；

【导师】 周德翼；

【作者基本信息】 华中农业大学 ， 农村中小企业管理， 2009， 博士

【摘要】 以粮食为原料的生物能源在全球的发展使世界的粮食安全问题面临新的情况。一方面发达国家通过发展生物燃料促进粮食的消费;另一方面发展中国家在促进粮食的生产,并且通过进口来解决本国的粮食安全问题。中国大豆市场面临着相似的情况。虽然从2002年开始,中国政府开始对大豆生产实施补贴政策,但是国内消费量的50%以上倚靠进口,在2003年,大豆进口占了总消费的60%以上。其中,美国是中国最重要的大豆进口来源地,2005年前,从美国进口的大豆量占了中国大豆进口份额的50%以上,2005年后从美国进口大豆也占到总进口的1/3以上。同时,中国是美国大豆最大的进口国。中国从美国进口大量的大豆,一方面是中国国内生产不能满足旺盛的需求,另一方面是美国大豆补贴政策使美国大豆在国际市场上具有较强的竞争力。美国以大豆为原料发展生物柴油使得中国的大豆市场面临新的情况。美国发展生物柴油的影响将会通过中美大豆贸易传导到中国的大豆市场,因而,本文的主要目的是分析美国发展生物柴油对中国大豆市场的影响。博弈的双方在制定政策进行决策时,行动往往会相互影响,理性的经济体会选择最优的政策来最大化自己的收益。在这个假定下,对于美国的政策及美国发展生物柴油的情况,中国政府会做出积极的反应。因而一个博弈模型将被用来模拟这个互动过程产生的结果。本文将计量模型和国家偏好函数模型通过差分博弈模型整合到一起,通过模拟方案分析得到实证的定量结果。中美两国大豆的供给模型、需求模型和中美两国大豆贸易模型中的参数在SAS软件中采用普通最小二乘法(ols)和两阶段最小二乘法(2sls)估计,参数的估计值基本通过了显著性检验,各个模型不存在自相关和异方差问题,且模型总体具有较好的模拟和预测功能。国家偏好函数被用来作为收益函数,国家偏好函数是包含了生产者福利、消费者福利和政府福利在内的有权重的可加函数。政治权重通过显示性偏好的方法求出。在中国大豆市场上,中国政府的政策是偏向于生产者的,近10年来的政治权重的平均值被用来进行模拟分析,其中生产者的政治权重为1.11,消费者的政治权重为0.89。美国对大豆生产者的偏好权重为1.34。参数估计的结果和政治权重被用于差分博弈模型中进行模拟方案分析。基期为2005年,是美国开始迅速发展生物柴油和《2005能源政策法》颁布的时间,基准方案设为中美两国没有任何积极的行动,即不采取任何补贴政策,美国不发展生物柴油,通过GAMS软件得到基准方案下的结果。情景分析主要是美国不发展生物柴油和发展生物柴油两种情况,美国发展生物柴油的假设为美国大豆产量的10%用于生物柴油的生产。在两种情景下,美国的策略方案为营销贷款项目、直接补贴项目、营销贷款项目和直接补贴项目组合策略、营销贷款项目与直接补贴项目与反周期补贴项目的组合策略;中国的策略方案为对大豆面积的1/3、2/3以及全部面积进行良种补贴。均衡结果通过重复剔除劣势策略得到。分析的结果表明在美国的每个行动方案下,比较两种情景下的均衡结果发现美国发展生物柴油,都将使得中国大豆的生产增加,总消费都将减少。中国大豆市场上的总福利都将上升,其中生产者的福利都会增加,消费者的福利都将减少,政府福利除在美国直接补贴行动下的均衡结果将增加外,在美国其他行动下的都将减少。在美国不发展生物柴油的假设下,纳什均衡策略组合为:美国的最优策略为营销贷款项目和直接补贴项目组合策略,中国政府的最优反应为对大豆全部面积进行补贴。美国以大豆产量10%为原料生产生物柴油的情景下,纳什均衡策略组合为:美国为营销贷款项目和直接补贴项目组合策略,中国政府的最优反应为对大豆全部面积进行补贴。相对于基准方案,美国不发展生物柴油情景的纳什均衡下,中国的大豆产量减少6.12%,总消费量增长8.88%;美国发展生物柴油情景的纳什均衡下,中国大豆产量减少5.50%,总消费量高8.40%,比美国不发展生物柴油情景下产量增加0.66%,消费量减少0.44%。从美国进口大豆的数量两种情景下的均衡量分别比基准方案高42.79%和28.29%,美国发展生物柴油情景下的进口量比不发展情景下减少10.15%。相对于基准方案,在两种情景下,中国大豆市场上的总福利都会降低,在美国不发展生物柴油的情景下,中国总福利下降27.24%,其中大豆生产者福利将减少37.54%,消费者福利会增加14.47%,政府福利减少96.35%:在美国发展生物柴油的情景下,相对于基准方案下的结果,中国总福利下降26.81%,其中大豆生产者福利将减少21.81%,消费者福利会增加4.83%,政府福利减少97.40%,相对于美国不发展生物柴油,中国总福利增长0.59%,大豆生产者福利将增长25.19%,消费者福利减少8.42%,政府福利减少28.72%。通过分析中美两国大豆政策互动过程中的纳什均衡,并将纳什均衡结果与基准方案下的结果进行比较,比较的结果表明无论在美国不发展生物柴油还是发展生物柴油的情景下,美国大豆的补贴政策都给中国大豆市场带来巨大的影响,抑制了中国大豆产量的增加,使得中国的总福利和生产者福利都受到损害。与美国不发展生物柴油情景下的均衡结果相比,美国发展生物柴油会使得中国大豆市场上的总福利提高,主要是由于中国大豆生产者剩余提高,中国大豆的生产会增加,但是消费量会减少。研究结果表明,在美国发展生物柴油和不发展生物柴油的情况下,中国的最优策略都是对全部大豆面积进行补贴。所以,为应对美国大豆政策及美国发展生物柴油的情况,中国应继续扩大大豆补贴面积,增加补贴方式,促进大豆的生产。同时,我国有必要积极利用WTO相关规则,对美国大豆补贴进行诉讼,以维护国内大豆生产者的基本利益。更多还原

【Abstract】 The world food security is confronted with a new situation of food-based biofuel booming worldwide. On the one hand, the developed countries are accelerating the food consumption by developing biofuel. On the other hand, developing countries are promoting food production, some of which depend on importing.The soybean market of China is faced with the similar situation. Although, Chinese government started subsidy policies on soybean production in 2002, still, 50% of the total consumption of soybean depends on import. America is one of the biggest soybean exporters of China. Before 2005, the quantity imported from US accounted for over fifty percent of China’s total import. Even after 2005, US shared one third market in China’s soybean import. Meanwhile, China is the largest importer of US’s soybean. The reason for China importing a mass of soybean from US is not only that the domestic production can not satisfy the increasing demand, but also that the subsidy polices of soybean in US make US a strong competitor in world soybean market.However, the soybean market is confronted with new situation that the US develops biodiesel using soybean as feedstock. The development of soybean-based biodiesel in US would have impact on China’s soybean market through trade. This study attempts to analyze the potential impact of US developing soybean-based biodiesel on China’s soybean market.In a game, when both players make decisions, the action adopted by players will influence each other. The rational government will choose the optimal policy to maximize its payoff. Chinese government will act positive to US’s action. A game-theoretical model is used to simulate the results of policy interaction. An econometric model and political preference function are incorporated into difference game model to do the scenario-based simulation in this study.The parameters in supply, demand and trade model are estimated in SAS system using ordinary least squares (ols) and two-stage least squares (2sls). Most of the estimated parameters are significant given the level of significance. There are no autocorrelation and heteroscedasticity in all the models. The models simulate the data well over the historical period and fit to predict.Political preference function is used as the payoff function. It is an addictive weighed function including producer welfare, consumer welfare and government welfare. Political weights are derived through revealed preference method. The results show that Chinese government has more preference on producer in soybean market. The average weights of recent 10 years are used in the simulation. The political weight of Chinese soybean producer is 1.11 and consumer is 0.89. The political weight of US soybean producer is 1.34. The estimated parameters and political weights are incorporated into the difference game model to do simulated analysis. The base year is 2005, which is the milestone of US biodiesel production and the year of the 2005 Energy Policy Act started. The base scenario is set that there are no positive actions in both China and US, which means that there are no any subsidy policies in both countries. Additionally, the production of biodiesel in US is set zero. The results under the base scenario are obtained in GAMS. The simulated policy scenarios of US are marketing loan program(ML), direct payment program(DP), combination of marketing loan program and direct payment program(MLD), combination of marketing loan program, direct payment program and counter-cyclical payments(MLDC). The simulated policy scenarios of China are subsidizing 1/3 of total planted acreage (SP1), subsidizing 2/3 of total planted acreage (SP2) and subsidizing total planted acreage (SP3). The scenario analysis is conducted in two situations, which are no development of biodiesel in US and 10% of production of soybean are used to produce biodiesel in US. Nash equilibrium is obtained through iterated elimination of weak dominated strategies.The equilibrium results of two situations are compared under alternative US actions. It turns out that the production of soybean in China will increase and the consumption of soybean will decrease under alternative US actions with US developing soybean-based biodiesel. And all the equilibrium total welfare and producer welfare in soybean market will increase, while all the consumer welfare will decrease. The government welfare will decrease except under the DP equilibrium.Under the situation of no development of biodiesel in US, the Nash equilibrium policies are MLD of US and SP3 of China. Under the assumption of 10% of production of soybean used to produce biodiesel in US, the Nash equilibrium policies are also MLD of US and SP3 of China. All the simulations are conducted in GAMS.The Nash equilibrium production of soybean in China will decrease by 6.12% and the consumption will increase by 8.88% under the situation of no development of biodiesel in US compared with the base scenario. Under the assumption of 10% of production of soybean used to produce biodiesel in US, the equilibrium production will decrease by 5.50% while the consumption will increase by 8.40% compared with the base scenario. The equilibrium production will increase by 0.66% and the equilibrium consumption will decrease by 0.44% under the situation of US developing biodiesel when compared with no development biodiesel in US. The soybean import from US under two situations will increase 42.79% and 28.29% respectively, and the import under developing biodiesel will decrease by 10.15% compared with the situation of no development of biodiesel. Compared with the base scenario, the total welfare will decrease under both the situations. Under the situation of no developing biodiesel in US, the total welfare of China will decrease by 27.24%, of which the producer welfare will decrease by 37.54%, the consumer welfare will increase by 14.47% and the government welfare will decrease by 96.35%. Under the situation of developing biodiesel in US, the total welfare of China will decrease by 26.81%, of which the producer welfare will decrease by 21.81%, the consumer welfare will increase by 4.83% and the government welfare will decrease by 97.40%. The results show that the total welfare will increase by 0.59%, of which producer welfare will increase by 25.19%, the consumer welfare will decrease by 8.42% and the government welfare will decrease by 28.27% under the situation of 10% soybean production used to produce biodiesel in US, compared with the situation of no development of biodiesel in US.The results show that the subsidies of soybean in US have tremendous impact on soybean market of China under both the situations by comparing the Nash equilibrium results of the two situation and the base scenario results. The subsidies of soybean in US restrain the soybean production in China and damage on the total welfare and producer welfare of China. Compared with the equilibrium results under the situation of no developing biodiesel in US, US developing biodiesel will increase the total welfare in soybean market of China due to the increase of soybean producer welfare, and the production of soybean will increase while the consumption will decrease.It turns out that the optimal policy of China is subsidizing the whole planted acreage of soybean whatever US develops biodiesel or not. Therefore, China is supposed to enlarge the subsidized acreage, work out more subsidies and promote the domestic production to against the bad impact brought by US soybean subsidies and the situation of US developing biodiesel. If necessary, Chinese government should institute proceedings of US subsidies to the WTO according to the WTO rules, to protect the soybean producer welfare from damage brought by US subsidy policy.更多还原