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The agriculture-urbanization nexus in economics: Three empirical studies.

机译：经济学中的农业-城市化关系：三个实证研究。

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摘要

This dissertation empirically examines the spatial and temporal relationship between agriculture and urbanization. It comprises of three empirical studies investigating the relationship from three different aspects.;The first empirical study quantitatively assesses how agricultural land quality has determined the spatial distribution of the urban population across the globe, and how that relationship has changed over time. It is an empirical validation of a conventional view in the narrative economic history literature, which maintains that the geographical distribution of urbanization was highly dependent on local agricultural land quality in early periods, whereas this relationship is much weaker in modern times. The study is based on global 0.5-degree grid cell data, and use the spatial negative binomial regression model to relate the urban population to agricultural suitability. It controls for other physical geographic factors, spatial interdependence between urban areas, and regional fixed effects. The model is estimated at various different points in time during the period ranging from 1000 CE to 2000 CE. The estimated coefficient of agricultural suitability first increased in early history (before 1500 CE), and then decreased over time. The inverted U-shaped pattern contradicts the predominant view in the literature, and is invariant under various robustness checks. It provides strong empirical evidence supporting the declining importance of fertile agricultural lands in determining locations of urbanization over time.;The second study examines how the role of agriculture in urbanization changes with economic openness. The literature offers conflicting views about the effect of agricultural productivity on a countries' urbanization level. Theoretical models suggest that the effect alters with economic openness; that the relationship between agriculture and urbanization is positive for closed economies and negative for open economies. However, until now the empirical validation for the interaction effect with economic openness is almost non-existent. Based on a panel of 97 developing countries spanning the period 1992-2012, this study specifies a panel smooth transition regression model in which the coefficient for agricultural productivity is allowed to vary as a logistic smooth function of a countries' degree of economic openness (measured by the international trade to GDP ratio). The results show that for economically closed countries the effect of agricultural productivity on urbanization is statistically significantly positive. As the degree of a country's trade openness increases, the effect declines. For the most open countries in the world, the effect is not statistically significantly different from zero.;The third case study empirically assesses whether the rapid urbanization in China has affected agricultural production based on panel data for 31 Chinese provinces from 2000-2011. There has been considerable debate on whether China's rapid urbanization threatened its agricultural production and subsequent food security, but so far most studies have used computable general equilibrium techniques for simulation and forecasting purposes, rather than providing a strong empirical test using historical, observed data. This study uses spatial panel models to examine whether the Chinese provinces with higher urbanization rates have experienced slower growth in agricultural output. The empirical results show no statistically significant evidence that agricultural growth was negatively associated with urbanization across provinces. Instead, we find agricultural growth was negatively correlated with initial yield levels in the provinces, positively correlated with land intensity, and negatively affected by natural disasters.
机译：本文从经验上考察了农业与城市化之间的时空关系。它包括三项实证研究，从三个不同方面进行了研究。第一项实证研究定量评估了农业土地质量如何决定了全球城市人口的空间分布，以及这种关系如何随时间变化。这是对叙述性经济史文献中传统观点的经验验证，该观点认为，城市化的地理分布在早期很大程度上取决于当地的农地质量，而在现代，这种关系则弱得多。该研究基于全球0.5度网格单元数据，并使用空间负二项式回归模型将城市人口与农业适宜性联系起来。它控制其他自然地理因素，城市区域之间的空间相互依赖性以及区域固定效应。在从1000 CE到2000 CE的各个不同时间点估计模型。估计的农业适宜性系数在早期历史中（公元1500年之前）首先增加，然后随时间而降低。倒U形图案与文献中的主流观点相矛盾，并且在各种鲁棒性检查下都是不变的。它提供了有力的经验证据，证明了肥沃的农业用地在确定城市化的位置随时间推移而日益下降的重要性。第二项研究考察了农业在城市化中的作用如何随着经济开放而变化。关于农业生产率对一个国家城市化水平的影响，文献提供了相互矛盾的观点。理论模型表明，这种影响会随着经济开放程度而改变。农业和城市化之间的关系对封闭经济是积极的，对开放经济是消极的。但是，到目前为止，几乎没有关于经济开放性的互动效应的经验验证。基于1992年至2012年期间97个发展中国家的面板，该研究确定了面板平滑过渡回归模型，在该模型中，允许农业生产率系数作为一个国家经济开放度的对数平滑函数进行变化（测得按国际贸易占GDP的比例）。结果表明，对于经济上封闭的国家，农业生产率对城市化的影响在统计上显着为正。随着一国贸易开放程度的提高，其影响会下降。对于世界上最开放的国家，其影响在统计上与零没有显着差异。第三例研究基于2000年至2011年中国31个省的面板数据，通过经验评估了中国的快速城市化是否对农业生产产生了影响。关于中国的快速城市化是否威胁到其农业生产和随后的粮食安全，一直存在着大量争论，但是到目前为止，大多数研究已经将可计算的一般均衡技术用于模拟和预测目的，而不是使用观察到的历史数据提供有力的实证检验。这项研究使用空间面板模型研究了城市化率较高的中国各省是否经历了农业产出增速放缓。实证结果表明，没有统计显着证据表明各省份的农业增长与城市化程度呈负相关。相反，我们发现农业增长与各省的初始产量水平呈负相关，与土地强度呈正相关，并受到自然灾害的不利影响。

著录项

  • 作者

    Li, Xiaofei.;

  • 作者单位

    Purdue University.;

  • 授予单位 Purdue University.;
  • 学科 Agricultural economics.;Economics.
  • 学位 Ph.D.
  • 年度 2015
  • 页码 193 p.
  • 总页数 193
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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