收储政策改革、劳动力约束与玉米供给反应机制研究——基于修正的Nerlove模型实证分析

Reform on storage policy,labor constraint and supply response of corn——An empirical study based on a revised Nerlove model

伴随粮食收储政策改革与农村劳动力快速流动,我国玉米生产出现了较大波动,甚至在玉米价格出现明显上涨的形势下玉米种植面积依然增长缓慢。为此,本文基于2002~2018年的省级面板数据,构建修正的Nerlove模型分析了收储政策改革和劳动力约束对玉米供给的影响机制以及供给影响因素,衡量不同条件下玉米供给弹性,进而剖析“市场化收购+生产者补贴”条件下玉米供给反应机制。结果表明:(1)临时收储政策改革前,政策实施区域(“三省一区”)的玉米供给明显高于其他区域,改革后,“三省一区”的玉米供给降低,其他区域的玉米供给增加,但“三省一区”的供给依然高于其他区域,两者差距缩小;(2)不断增加的劳动力约束对玉米供给产生明显负向影响;(3)综合考虑二者影响,政策改革前玉米供给得到较大提升,改革后玉米供给出现小幅度下降。政府应该关注收储政策改革后农户面临的市场风险和劳动力约束,制定适当的支持政策,以稳定农民收入,保障玉米供给。

With the reform of grain purchasing and storage policy and the rapid flow of rural labor force,corn production in China has experienced great fluctuations.Even though the price of corn has obviously increased,the corn planting area is still growing slowly.Based on provincial panel data from 2002~2018,this paper constructs a revised Nerlove model to dissect the mechanism of the impact of storage policy reform and labor constraints on farmers corn supply response,and the factors influencing supply response,and measure the supply elasticity under different conditions.The results show that:①Before the temporary purchasing and storage policy reform,the corn supply in the policy implementation area(“three provinces and one district”)was significantly higher than that in other areas.After the reform,the corn supply in“three provinces and one district”decreased,while the corn supply in other areas increased,but the corn supply in“three provinces and one district”was still higher than that in other areas,and the gap between them became smaller.②Increasing labor constraints have a significant negative impact on corn supply.③Considering the influence of the two factors,the corn supply has been greatly improved before the policy reform,and declined slightly after the reform.The government should pay attention to the market risks and labor constraints faced by farmers after the reform of purchasing and storage policy,and make appropriate supporting policies to stabilize farmers’income and ensure corn supply.