粮食安全的价格理论框架及其应用

在建立特定非线性粮食供给和需求函数的基础上,发展了一个解析非线性均衡蛛网模型,表明一般性的粮食价格波动能够收敛,只有粮价超过一定幅度才发散震荡并形成粮食灾难.政策视角的粮食安全概念必须建立在国家层次,将粮价控制在安全区域内是粮食安全政策的主要内容,短期内通过粮食储备和价格政策控制粮价,长期内扩大粮食波动的安全区域.应用分析表明发展“生物燃料”、保持“耕地红线”有利于保证一国的粮食安全.

A Price-Theory Framework of Grain Safety and Its Application

An analytic nonlinear equilibrium cobweb model is developed to describe the economical behaviors of demanders,suppliers and prices based on the nonlinear supply-demand function obtained at different price levels.From this model,the ordinary fluctuations of the grain price are convergent.However,in the case that the grain price is over a threshold,a divergent fluctuation behavior is observed,implying the risk that could break the grain safety.One of the main contents of grain-safety policies is then to limit the grain price fluctuation within a safe range.That is,in the short run to control grain price with grain reserve and prices management,and in the long run to enlarge the safe field of grain price changing by increasing price elasticity of grain demand and decreasing price elasticity of grain supply.Furthermore,from the analysis through the use of the model it is found that developing biological fuel with grain and controlling the area of cultivated land could contribute benefits to maintaining the grain-safety status of one country.