公路基础设施与农业劳动生产率

Highway infrastructure and agricultural labor productivity

中国政府对农村地区进行了大规模的交通基础设施投资。尽管交通基础设施投资被认为有助于促进农业发展,但是关于其如何影响农业劳动生产率的实证研究仍然较少。利用中国1999—2011年县级面板数据和同时期的交通地理数据,通过构筑准自然实验,并使用双重差分方法,研究了高速公路开通对中国农业劳动生产率的影响及其作用渠道。研究发现,公路基础设施可以显著提高农业劳动生产率。同时,采用多种计量方法处理了高速公路线路规划的非随机性导致的模型估计内生性问题,结果依然稳健。具体来说,高速公路开通使得县域农业劳动生产率每年提高约6%,其中,平原地区农业劳动生产率的提升幅度明显高于丘陵和山地地区。在因果关系的识别中发现,高速公路的开通可以通过提高农业机械化水平、促进劳动力非农转移和提升市场准入水平,进而提高农业劳动生产率。通过异质性分析还发现,公路交通基础设施对贫困县农业劳动生产率提升的影响显著高于非贫困县。

China has made large-scale investments in transport infrastructure for rural areas.Although investment in transport infrastructure is considered to help promote agricultural development,empirical studies on how it affects agricultural productivity are still scarce.Based on China’s county level panel data from 1999 to 2011 and the traffic geographic data of the same period,this paper studies the influence of highway opening on China’s county agricultural labor productivity and the specific impact channels by constructing quasi-natural experiments and using the difference-in-difference method.This paper finds that highway infrastructure can significantly improve agricultural labor productivity.At the same time,this paper deals with the endogenous problem of model estimation caused by the non-randomness of highway route planning with multiple measurement methods,and the results remain robust.Specifically,the opening of highways leads to an increase in agricultural labor productivity of about 6%per year in counties,with the increase in agricultural labor productivity in plains significantly higher than in hilly and mountainous areas.In the identification of causal relationships,this paper finds that the opening of highways can improve agricultural labor productivity by increasing the level of agricultural mechanization,promoting off-farm labor transfer,and improving market access.Through heterogeneity analysis,this paper also finds that the impact of highway infrastructure on agricultural labor productivity improvement in poor counties is significantly higher than that in non-poor counties.