| Corn demand in our country was expanding constantly in recent years, the cognition of balance situation between corn supply and demand emerged differences. Some scholars showed their optimistic attitudes, believed that corn supply could meet the increasing demand in our country; however, there were researchers also expressed their anxious thoughts, they considered the situation was becoming more nervous, we had to expand import to satisfy the growing corn demand. With the rising and development of biomass energy, corn functions had enlarged from the"cereal crops, commercial crops and forage crops"to the"cereal crops, commercial crops, forage crops and energy crops". The development of biomass energy aroused food prices'rising in the globe, pepole had different understandings of the prospects of biomass energy's development in our country, supporters claimed that biomass energy had weak impact on the environment, and also can help us to alleviate the tense situation of energy supply and demand; opponents argued that the biomass energy may affect our corn supply security, and even threaten food security, initiated the condition of"cars seized grain from humanity". The trifling change of Corn supply seemed to cause significant changes of food security and husbandry, the variation of the relationship between corn supply and demand would affect the overall economic development in our country. Based on this background, this dissertation studied the present situation of corn supply and demand in China, and forecasted the supply and demand in the coming years, analysed the fluctuation of corn trade and varaition of corn international competitiveness in China, estimated the relation of corn supply and demand. In addition, this paper also discussed the influence of biomass energy to the corn supply and demand.The research results of the current corn production showed that corn was becoming an increasingly important cereal crop. Its output occupied more than 30% of crops production already. Corn planting area expanded unceasingly, yield increasing slowly and fluctuated frequently, the speed of area's augment was greater than the increase of yield, the increase of corn output in our country mainly depended on the planting area's expansion, yield ability still had large room to be improved. According to the regional differences of corn production, we divided China into northern, central and southern producing districts, studied the varaiton trend of corn production. The conclusion told us that each region increased its corn production in a distinctive way. The corn production increase in northern region mainly relied on the expansion of planting area, the southern region's corn production emphasized the raise of yield, the difference between the contribution of planting area and yield in the central area was small.On the basis of three divisions, we built corn supply response models of each region, measured the supply response of corn yield and planting areas, and studied different factors'influences on corn production. The calculated results told us, the values of planting areas'short-term elasticities were 0.35, 0.40 and 0.19, the short-term yield elasticities were 0.15, 0.09 and 0.01 respectively; the long-term flexibilities for planting areas were 5.88, 9.41 and 8.54, and long-term elasticities of yield were 0.22, 0.14 and 0.08. Therefore, whether from a long-term or short-term perspective, the price elasticicities of planting areas were larger than the yield. Furthermore, the long-term effects were superior to the short-term effects. In addition, the natural disasters, chemical fertilizer and wheat prices brought distinctive influences on corn yield and planting areas in three divisions.Through the demand analysis, we got the research conclusion that corn demand was expanding constantly, but the demand structure had changed. From 1995 to 2008, the corn rations proportion dropped from 17.56% to 6.09%, feed consumption proportion declined from 71.73% to 65.89%, and the share of industrial processing corn demand increased from 5.76% to 23.37% quickly. Total rations demand decreased, but the variation trends of rural and urban residents were quite different. The income elasticity and price elasticity of urban residents'corn consumption were 0.44 and -0.32 respectively, while the rural residents'income elasticity and price elasticity were -0.27 and -0.11. The influences of income and price on urban residents'corn consumption were greater than the rural residents. In addition, the value of feed corn demand increased, but the proportion declined; the value and propotion of industrial processing corn both enhanced. Under the background of global food prices' rising, China's corn stockpiles increased unceasingly.With the declining of corn export volume, the corn trade status of China had changed. In 2008 and 2009, the international corn market share of China was less than 0.5%; corn trade competitiveness fell, trade competitiveness indexes of China's corn decreased to 0.74 and 0.39 respectively; corn revealed comparative advantage indexes were only 0.03 and 0.01, China's corn did not have comparative advantages anymore. Most of corn production in our country was used to meet domestic demand, corn market prices were mainly affected by the selling prices of households, peasants'selling prices increased 10% would bring market prices increased 7.51%. The share of corn exports of China had been shrinking, and our corn import volume was very limited at present, therefore the domestic corn market prices were influenced by the international price less than the households'selling prices.The projection showed that, the corn supply of our country would fall short of demand in the next years. The research results of welfare effects of the corn prices'change and technical progress indicated that, prices'rising and technical progress both can improve our benefits, but their welfare distribution orientations were opposited. Corn prices'rising 10% lead to producers'welfare increasing 17.50 billion yuan and consumers'welfare decreased 0.16 billion yuan in the short run, and brought producers'welfare increasing 17.67 billion yuan and consumers'welfare reduced 0.15 billion yuan in the long run. The technological progress lead to the improvement of overall benefit levels, but the distribution was not balanced between consumers and producers, consumers'welfare improved and producers'welfare decreased.On the basis of forecast corn supply of three producing regions, we calculated the per unit yield, planting area and output of corn. Projections showed that, by 2020, per unit yield of corn in China would be raised to 5703.47 kilograms per hectare, the planting area would expand to 358 million hectares, and the production would increase to 2039 million tons. We constructed trend models to forecast corn demand volume of different categories, added the different demand volumes and obtained the aggregation of corn demand. Forecasting results indicated that, by 2020, corn demand would reach to 2084 million tons, the gap between supply and demand would reach to 45 million tons. The development of biomass energy would promote the demand of corn, initiate corn prices rising, and then encourage farmers to improve corn yield and enlarge the planting area of corn, but it would also lead to the reduction of other crops planting area, this would be an ordeal to the security of food supply in our country.Eventually, based on the above analysis, this study pointed out some problems of the development of corn industry in our country, and put forward some specific countermeasures, such as promoting scientific achievements actively, improving efficiency of corn supply , strengthen national macroeconomic regulation and accelerating the construction of law system and institutions, in hopes that provided theoretical supports for corn production and welfare distribution, and provided references for biomass energy policies and corn industry policies'formulation. |
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