中国棉花生产要素替代及区域异质性

Factor substitution and regional differences of cotton production in China

为稳定国内棉花生产,适度恢复长江和黄河流域棉区产能提供可行建议,利用要素弹性变化解释棉农的生产决策行为逻辑,先采用超越对数成本函数和似不相关回归估计棉花生产要素成本份额方程,再计算出要素需求弹性和影子替代弹性。结果表明:1)整体来看,我国棉花生产中劳动力和化肥需求缺乏弹性;机械需求弹性呈下降趋势,从富有弹性变为缺乏弹性。2)劳动力、化肥和机械两两之间相互替代,机械与劳动力的替代关系最强,化肥与劳动力的替代关系最弱。3)棉区间的差异主要在于黄河和长江流域棉区的机械需求始终富有弹性,且化肥对劳动力的替代弹性整体下降;而西北内陆棉区的机械需求开始缺乏弹性,化肥对劳动力的替代弹性则有所增长。因此,西北内陆棉区需合理控制机械价格,又要警惕化肥投入过量导致的环境负外部性;而黄河和长江流域棉区则应着力提升棉花生产机械化水平,既要增加与当地棉花生产配套的机械供给,又要利用政策工具有效调控机械需求。

In order to provide feasible suggestions for stabilizing domestic cotton production and moderately restoring the production capacity of cotton areas in the Yangtze and Yellow River basins,the study explained the behavioral logic of cotton farmers'production decision using elastic changes in factors.The trans-log cost function and seemingly uncorrelated regression were employed to estimate the cost share equation of major inputs in cotton production.On this basis,the demand elasticity for each factor and substitution elasticity were calculated.The results showed that:1)The demand for labor and chemical fertilizer was lack of elasticity in China's cotton production,while the elasticity of mechanical demand declined and turned from elastic to inelastic.2)There was a mutual substitution among labor,chemical fertilizer and machinery input,and the substitution between machinery and labor was the strongest and the weakest between fertilizer and labor.3)When it came to different cotton areas,the machinery demand was always elastic and the elasticity of fertilizer-labor substitution declined during the study period in the Yellow River and Yangtze River basin cotton-growing area.In the northwest cotton-growing area,the machinery demand turned to be inelastic and the fertilizer on the elasticity of substitution for labor increased.Therefore,we suggested that the northwest cotton-growing area need control the price of machinery reasonably,as well as be vigilant about the negative environment externality caused by excessive input of fertilizer.The Yellow River and Yangtze River basin cotton-planting area should focus on the mechanization of cotton production to enhance the supply of technology and machinery suitable for local cotton production and apply the policy instrument effectively to stimulate the demand for machinery.