The average farm size is an important indicator of agricultural sustainability. Over the last decades, farmers in the European Union (EU) Member States faced multiple changes of business environment that fuelled shifts in agricultural land use and farm structure. The aim of this paper is to develop and employ a novel index decomposition analysis framework that allows decomposing the changes in the average farm size into pure farm size change and structural effects (specialization and spatial distribution). The empirical research covers the period of 2005–2016 and considers the three levels of aggregation: the EU, Member States, and farming types. Results indicate a remarkable growth in the average farm size at the EU level over 2005–2016. Chain-linked analysis shows that the steepest increase in the average farm size is observed following switch from coupled to decoupled direct payments. Findings suggest that the most serious increase in the average farm size was observed for field crop and specialist grazing livestock farms. Although the main effect contributing to the change in the average farm size at the EU level was the pure increase in the average farm size, results confirm that structural effects also played an important role. However, the contribution of structural effects varies across types of farming and the Member States.

农场的平均规模是农业可持续性的重要指标。在过去的几十年中，欧洲联盟（EU）成员国的农民面临着商业环境的多种变化，加剧了农业土地利用和农场结构的变化。本文的目的是开发和采用一种新颖的指数分解分析框架，该框架可以将平均农场规模的变化分解为纯农场规模的变化和结构效应（专业化和空间分布）。实证研究涵盖了2005-2016年，并考虑了三个总体层次：欧盟，成员国和农业类型。结果表明，在2005-2016年间，欧盟平均农场规模显着增长。连锁分析表明，从直接支付转为解耦直接支付后，可以观察到平均农场规模的最大增长。研究结果表明，在田间作物种植场和专业放牧牲畜场中，平均农场规模增长最为严重。尽管促成欧盟平均农场规模变化的主要影响是平均农场规模的纯粹增加，但结果证实结构性影响也发挥了重要作用。但是，结构效应的贡献因农业类型和成员国而异。尽管促成欧盟平均农场规模变化的主要影响是平均农场规模的纯粹增加，但结果证实结构性影响也发挥了重要作用。但是，结构效应的贡献因农业类型和成员国而异。尽管促成欧盟一级平均农场规模变化的主要影响是平均农场规模的纯粹增加，但结果证实，结构效应也起着重要作用。但是，结构效应的贡献因农业类型和成员国而异。