机械化水平对农户种植结构的影响研究——基于IVGMM和IVTobit的估计方法

目的]农业种植结构是农业供给侧结构性改革的关键所在,农业供给侧结构性改革又是乡村振兴战略的必由之路。采用农户实地调查数据,分析机械化水平对农户种植总面积、粮食作物种植面积、经济作物种植面积、粮食作物种植面积比例的影响,以期为农业种植结构调整提供科学参考。方法]为解决传统回归方法中内生性和样本选择偏误问题,运用工具变量法和样本选择修正法探究机械化水平对农户种植结构的实际影响。结果]机械化水平对农户种植结构有显著的正向影响,机械化水平每提升1%,农户种植总面积增加0.428%,粮食作物种植面积增加0.435%,经济作物种植面积就增加0.111%,粮食作物种植面积比例增加1.104%。结论]机械化水平对农户种植面积有稳健的正向效应,特别是对农户粮食作物种植面积的正向效应更大。与样本修正后工具变量估计相比,普通最小二乘估计会严重低估机械化水平对种植结构的影响。

STUDY ON THE EFFECT OF MECHANIZATION ON FARMER′S PLANTING STRUCTURE——ESTIMATION METHOD BASED ON IVGMM AND IVTOBIT

The structural reform of the agricultural supply front is the necessary path to realize the strategy of rural vitalization,while determining the structure of agricultural planting is the key procedure within that structural reform.This study aims at analyzing the impact of the level of mechanization on the total area planted by farmers,the area planted with grain crops,the area planted with cash crops,and the proportion of the area planted with grain crops,so to provide scientific references for the adjustment of agricultural planting structure.The data in this study was collected by field survey.In order to solve the problems of endogeneity and sample selection errors that may exist in the model,instrumental variable method and sample selection correction method were used to explore the actual impact of mechanization level on the farmers'planting structure.It was found that the level of mechanization had a significant positive impact on the planting structure of farmers.For each 1%increase in mechanization level,the total area planted by farmers,the area planted with grain crops,the area planted with cash crops,and the proportion of area planted with grain crops would increase by 0.428%,0.435%,0.111%,1.104%,respectively.The level of mechanization has stable positive effects on the area planted by farmers,especially on the area planted with grain crops.Moreover,the instrumental variable estimating method after a sample-modification used in this study can amend the severe underestimation of the impact of mechanization level on agricultural planting structure by ordinary least squares estimates.