英文文献：Government Payments and Farmland Concentration-政府支付和农田集中
英文文献作者：Roberts, Michael J.,Key, Nigel D.
英文文献摘要：
Over the last twenty five years commodity crop farms have steadily declined in number and grown in average size, and production has shifted to larger operations. During the same period, the share of agricultural payments going to large farms has increased, in large part because payments are tied to actual or historical crop production. This study evaluates whether payments from federal farm programs may have contributed to the concentration of farmland. Using zip code-level data constructed from the micro files of the 1987-2002 Agriculture Censuses the study estimates the association between government payments per acre and subsequent growth in weighted median farmland area. A semi-parametric generalized additive model controls for location and initial concentration levels, and narrows comparisons to nearby zip codes with similar average farm sizes. Findings indicate, both with and without spatial controls, that government payments are strongly associated with subsequent concentration growth.

在过去的25年里，商品作物农场的数量稳步下降，平均规模不断扩大，生产转移到更大规模的经营中。在同一时期，流向大型农场的农业补贴比例有所增加，这在很大程度上是因为补贴与实际或历史上的作物产量有关。这项研究评估了联邦农业项目的支付是否对农田的集中有贡献。利用1987-2002年农业普查微观文件中建立的邮政编码级别的数据，该研究估计了每英亩政府支出与随后加权平均农田面积增长之间的关系。半参数广义加性模型控制了位置和初始浓度水平，并缩小了与附近具有相似平均农场规模的邮政编码的比较。研究结果表明，无论是否有空间控制，政府支付都与随后的集中度增长密切相关。