全球中长期粮食供需趋势分析

经济全球化背景下,世界粮食供需的扩张和收缩、国际粮食价格的波动,对于我国通过粮食贸易平衡国内粮食缺口具有重大影响。因此,非常有必要对全球中长期粮食供需趋势做出较为准确的估计。首先分析了粮食需求和粮食收益率的影响因素,发现人均收入、饮食结构、人口增速、粮食价格及生物能源的发展,决定了世界人均粮食需求的走势,而粮食收益率很大程度上受化肥密集度、土地开发程度、机械化程度和灌溉比例的影响。然后采用趋势外推和指数平滑等方法,在预测人均粮食需求和粮食收益率的基础上,基于联合国人口司中等人口增速的假设,预测了2015-2050年全球粮食供给和需求变化趋势。结果表明：未来粮食收益率期望增速降低,种植面积预期保持稳定,小麦和稻米人均需求预期稳定,玉米和大豆人均需求预期迅速上升,全球粮食供需预期基本平衡,但存在结构性失衡,稻米和大豆将出现缺口。

Analysis on Mid and Long-term Global Food Supply and Demand

Under economic globalization, the expansion and contraction of world＇ food supply and demand,and international grain price fluctuations, have a great influence on China to fill its domestic food gap through trade. Therefore, it is very necessary to accurately estimate the long-term global food supply and demand trends. This paper first analyzes the factors that influence the demand for food and grain yield and finds that per capita income, dietary structure, population growth, food prices and the de- velopment of bioenergy determine the future trend of the world demand for food. ; while grain yield is affected to a great extent by the fertilizer concentration, degree of land development, mechanization de gree and the influence of irrigation rate. Based on the estimation of per-capita food demand and grain yields, this paper then adopts trend extrapolation and exponential smoothing model to estimate changing tendency of food supply and demand from 2015 to 2050 in accordance with UN population division＇s hy- pothesis of moderate population growth. The result shows that grain yields growth will be lower in the future, harvested areas will be stablized, wheat and rice demand per capita will be also stablized and corn and soybean demand per capita will remarkably be increasing. In summary, the global food supply will be basically equal to demand,but structural imbalance still exists and there will be rice and soybean gap.