英文文献：The Structure and Profitability of Organic Field Corn Production-有机田玉米生产的结构和盈利能力
英文文献作者：McBride, William D.,Greene, Catherine,Foreman, Linda
英文文献摘要：
Results from long-term experimental trials suggest that similar yields and lower costs are possible from organic compared with conventional field crop production, but there is little information about the relative costs and returns on commercial farms. This study examines the structure and profitability of field corn production using a nationwide survey of corn producers for 2010 that includes a targeted sample of organic growers. Propensity score matching was used to develop a sample of similar conventional and organic farms based on farm and operator characteristics. Treatment-effect models were estimated using the matched sample to isolate the effect of choosing the organic approach on various levels of corn production costs. The procedure accounts for the impact of both observable and unobservable variables on corn production costs.

长期试验的结果表明，与传统的田间作物生产相比，有机作物有可能获得类似的产量和更低的成本，但关于商业农场的相对成本和回报的信息很少。这项研究通过对2010年全国玉米生产者的调查，包括有机种植者的目标样本，调查了大田玉米生产的结构和利润。基于农场和经营者的特征，采用倾向评分匹配的方法开发了相似的传统农场和有机农场样本。利用匹配的样本估计处理效应模型，以分离选择有机方法对不同水平玉米生产成本的影响。该程序考虑了可观察变量和不可观察变量对玉米生产成本的影响。