改革开放以来中国耕地利用与粮食生产安全格局变动研究

The Variation of Farmland Use and the Security Pattern of Grain Production in China since 1978

利用农业统计数据,分析自改革开放以来我国耕地集约利用水平的时空动态格局,构建"粮耕弹性系数"来反映耕地资源变化与粮食生产的互动关系。揭示出:①耕地投入的增加和质量的提升在一定程度上缓解了改革开放以来我国耕地资源严重流失给粮食生产安全带来的压力;②自改革开放以来,全国耕地集约利用水平呈现由经济快速发展带来的普遍性提升局面,并随着经济发展程度及其增长速率由东南沿海向内陆递减,耕地集约利用水平的提升速率也呈现由东南沿海向内陆梯级递减态势,同时这种提升态势将随着时间和经济发展而出现由沿海地区向内地的推移;③耕地集约利用程度的不断提升,并不一定会带来粮食产量的持续稳定增长。耕地集约利用增长的边际效用递减特性,使得在经济较发达的情况下,粮食生产安全的保障已逐步由耕地集约利用水平的提升转向了耕地面积的保护,由此导致耕地资源的数量成为了左右粮食生产安全的关键,这也为当今制定严格的耕地保护目标和战略提供了现实的科学依据。

With rapid development of China＇s economy,the farmland use pattern has greatly changed since economic reforms were launched in 1978.On the one hand,rapid industrialization and urbanization has resulted in the agricultural to non-agricultural land conversion,and some farmland idle due to the massive and sustained flow of rural-to-urban labor migration;on the other hand,economic development may ensure the improvement of infrastructure for agricultural production,and the enhancement of farmland intensive use level.The dual variation of farmland both in quantity and quality brought about the effects to different degrees on grain production.This paper analyzes the spatio-temporal pattern of China＇s farmland intensive use level between 1978 and 2004,and develops a farmland-grain elasticity coefficient to reflect the interrelationship between farmland and grain production,using the agricultural statistical data from local governments.The outcomes indicated that,since 1978,the pressure of tremendous farmland loss on grain security has been relaxed,to some extent,due to the increased investment and subsequent quality improvement in farmland.Since the initiation of economic reforms,China＇s farmland intensive use level has been generally improved due to rapid economic development,and the improving speed takes on a situation of gradient declining from southeast coastal China to hinterland,just as the declining gradient of economic development level.Furthermore,the existing posture will be passed from coastal China to hinterland with the economic development.However,unceasing improvement of farmland intensive use level can not always bring about the sustainable and steady growth in grain outputs.Therefore,considering the law of diminishing marginal utility,in the economy relatively developed countries,the quantity of farmland will play a key role in maintaining the security pattern of grain production,which also provides a practical scientific basis for nowadays constituting strict farmland protection objective and strategy in China.