20世纪60年代以来日本耕地面积变化及其启示

本文截取1961年以后日本经济发展相对平稳的时间段,研究耕地面积变化及其驱动机制,可以在一定程度上避免重大历史事件对统计数据的干扰,从而得出符合社会发展规律的结论。研究结果表明,1960年以来日本耕地面积和人均耕地面积一直呈下降趋势,到2003年分别为1961年的79%和60%,符合直线变化规律。单位农业劳动力占有的耕地面积从1961年的0.2060hm2/人上升至1.0870hm2/人,接近1961年的5倍,符合二次曲线变化规律。借助主成分分析和回归分析方法对耕地面积驱动力的研究结果表明,经济发展造成的工业用地和城市用地面积扩大是耕地面积减少的根本原因;农产品价格的变化也造成部分耕地退出耕作;随着经济技术水平的提高和防灾减灾能力的增强,因自然灾害造成的耕地损失逐渐减少。增加耕地面积的诸因素中,土地开垦始终处于主导地位,其次为土地整理和复垦。在我国未来的经济发展过程中,要摒弃城市化进程中后期耕地流失会相应减少的观念;警惕加入WTO之后,农产品市场开放可能对粮食安全和我国耕地面积的影响;同时还要坚持耕地保护政策的持久性。

The Change of Arable Land Area in Japan since the 1960s and Its Policy Implications

Historic events may have great effects on the statistical precision when long-time series data are used in study.In order to avoid disturbance of historic events on natural law of economical development and its effects on arable land change,this paper took arable land change in Japan as an example.The results clearly showed that arable land area and arable land per capita have linearly-decreased all the time.Compared with the result in 1961,only 79% of total arable land and 60% of arable land per capita were left in 2003.Arable land per agricultural labor increased to 1.0870 ha in 2003,more than four times than that in 1961,which is suitable to the rule of conic.Under aid of factor analysis(principal components) and stepwise regression methods,the expansion of industrial land and urban land,which is caused by economical development,was the fundamental cause of the arable land area decrease;the price fluctuation of agricultural products also led to partial arable land retreat from cropping;the loss of arable land,caused by natural disaster,was obviously decreased along with the improvement of capability of disaster reduction and prevention.The land reclamation was the most important factor as the cause of the arable land area increase.The land consolidation and re-reclamation followed.For the economic development in the future,the notion that arable lands loss will be gradually decreased as urbanization rate comes to be stable should be given up.During the process of urbanization,the urbanization is not the primary driving forces of arable land loss but economic development.What researchers focus on should be abnormal loss of arable land caused by extensive urban expansion and economic activities.Because of the price gap of crops between internal and external agricultural markets,more and more attentions should be paid to the effects of food security and arable land change after opening the agricultural markets to the world;some issues should be taken into account in advance,such as whether the policy "abandonment of arable land" might be adopted when there is little benefits in agriculture under the preconditions that conversion of abandoned arable land to builtup is absolutely prohibited.Additionally,the measures to protect and increase arable land area should be stable and never be changed as the pressure from urbanization mitigates,because arable land is a kind of rare and nonrenewable resource.