前沿 | 复旦经院奚锡灿等在《美国科学院院刊》(PNAS)上发表文章

Policy Simulation Laboratory, Zhejiang University

Xican Xi

China Center for Economic Studies, School of Economics, Fudan University,

Xin Tang

Center for Economic Development Research, Economics and Management School of Wuhan University

Deming Luo

Center for Research of Private Economy, School of Economics, Zhejiang University

Baojing Gu

Department of Land Management, Zhejiang University

Shu Kee Lam，Deli Chen

School of Agriculture and Food, The University of Melbourne

Peter M. Vitousek

Department of Biology, Stanford University

Abstract:

化肥和农药等农用化学品的过度施用，严重威胁了我国的生态环境和人民身心健康，对我国农业的可持续发展提出了严峻挑战。本研究发现，农业经营规模是影响我国农用化学品施用量的重要因素。利用从中国农村家庭调查数据库（CRHPS）调取的数据，本研究发现，控制其他因素后，户均耕地面积每增加1％，每公顷化肥和农药施用量分别下降0.3％和0.5％，而农业劳动生产率则上升几乎一个百分点。利用不同来源的农业调查数据，本研究得出了非常相似的结论。发达国家的历史经验表明，农业经营规模一般随着经济发展而扩大。在我国，由于劳动力市场和农地使用权市场存在严重的资源错配，尽管我国宏观经济在过去四十年间快速持续发展，农业经营规模却没有相应扩大。本研究的结论表明，消除劳动力市场和农地使用权市场的资源错配，适度扩大农业经验规模，可以有效减轻我国农用化学品的过度施用问题。

Understanding the reasons for overuse of agricultural chemicals is critical to the sustainable development of Chinese agriculture. Using a nationally representative rural household survey from China, we found that farm size is a strong factor that affects the use intensity of agricultural chemicals across farms in China. Statistically, a 1% increase in farm size is associated with a 0.3% and 0.5% decrease in fertilizer and pesticide use per hectare (P < 0.001), respectively, and an almost 1% increase in agricultural labor productivity, while it only leads to a statistically insignificant 0.02% decrease in crop yields. the same pattern was also found using other independently collected data sources from china and an international panel analysis of 74 countries from the 1960s to the 2000s. while economic growth has been associated with increasing farm size in many other countries, in china this relationship has been distorted by land and migration policies, leading to the persistence of small farm size in china. removing these distortions would decrease agricultural chemical use by 30–50% and the environmental impact of those chemicals by 50% while doubling the total income of all farmers including those who move to urban areas. removing policy distortions is also likely to complement other remedies to the overuse problem, such as easing farmer's access to modern technologies and knowledge, and improving environmental regulation and enforcement.

Keywords

crop yield；environmental protection；fertilizer use efficiency；socioeconomic； barriers urbanization

《美国科学院院报》（PNAS）是世界上久享盛誉的综合性期刊，收录的文献涵盖医学、化学、生物、物理、大气科学、生态学和社会科学等领域。自1914年创刊至今，PNAS提供具有高水平的前沿研究报告、学术评论、学科回顾及前瞻、学术论文以及美国国家科学学会学术动态的报道和出版。