土地流转背景下农户经营规模与土地生产率关系再审视——来自固定粮农和地块的证据

Re-Exploration of the Inverse Productivity-Size Relationship Using the Fixed Farmers’Fixed Plots Data in the Context of Land Transfer

农户经营规模和土地生产率关系是发展经济学领域的经典议题之一。本文在土地流转加速发展的背景下讨论了我国农户经营规模扩大对土地生产率的影响以及测量两者之间关系面临的种种干扰。除了农户规模本身的作用外,理论和实证检验均表明存在土地流转市场时不同规模农户在土地生产率上的差异还可能源于农户和土地的异质性,譬如土地更多流向经营能力强的农户、流转多劣地等等。基于固定农户的固定地块数据可以有效控制异质性的实证策略,本文利用4个省两期跟踪调查数据对两者关系进行了再检验。研究发现,来自固定农户固定地块的证据表明农户土地经营规模扩大并不会影响粮食单产,而不控制固定地块时往往会得到两者负相关的伪结论,并且仅控制固定农户时上述伪结论更为明显。这一结果意味着不必担心规模经营会威胁粮食供给。

The relationship between farm size and land productivity is one of the most classical issues in development economics.This paper re-explores the relationship between farm size and land productivity,particularly concerned about measurement issues.We first attempt to construct a conceptual framework taking account of land transfer market.We find that the differences in land productivity among farmers of different sizesare not only due to size itself,but also to the heterogeneity across households and plots(and area measurement error).We then exploit the plot-specific panel feature and intertemporal farm size variation,of the fixed farmers’fixed plots data,to estimate the effects of size on plot-specific crop yields using plot fixed effects.The empirical results indicate that eliminating specific unobserved characteristics eliminates the estimated inverse productivity-size relationship.This means that in current Chinese agricultural production,heterogeneity issues,rather than farm size can suffice to explain differences in land productivity among farmers.