美国特拉华大学地球、海洋与环境学院的Enze Jin、Nicolas Al Fahel和Cristina L. Archer*等人选择特拉华州是因为它是一个相对较小的州（只有3 个郡），拥有公开可用的高分辨率地理空间数据集，并且玉米为主要农作物类型。研究发现，在小型农场中，田间作业的能源使用是玉米生产中能耗最大的部分，而在中型和大型农场中，干燥过程需要的能源最高。我们的结果还表明，大中型农场的玉米生产比小型农场的能源效率更高，尽管小型农场每单位玉米产品的电力消耗和地下水灌溉量较小。在特拉华州的3 个郡中，苏塞克斯（Sussex）的玉米生产能耗最高，而肯特（Kent）的最低。在特拉华州，玉米生产平均需要42,789 百万瓦的电力、420 万加仑的柴油、140 万加仑的汽油和310 万加仑的液化石油气，得出的食物能源足迹为每蒲式耳38,171 Btu或682 Btu/lb。
食物能源足迹评估可以使消费者了解食物的能源投入，并为利益相关者和政策制定者提供有用的见解，为食品行业制定更可持续的战略。这项研究的新颖性是建立用于玉米生产的食物能源足迹的地理空间清单。而且，所提出的方法完全基于公共数据，并且很可能推广到其他州以及其他农作物。
Abstract
Energy footprint of food: The case of corn production in Delaware
Enze Jin, Nicolas Al Fahel, Pinki Mondal, Hong Li, Cristina L. Archer
College of Earth, Ocean, and Environment, University of Delaware, Newark, DE, USA
Food production is an energy‐intensive process, especially for crops and meat. However, the link between food and the energy consumed to produce it is less transparent to customers and there is a lack of energy footprint information for food production in the market. This study develops a geospatial approach for estimating the direct energy use for food production, that is, the Energy Footprint of Food (EFF), and tests it for one crop in one U.S. state, that is, field corn in Delaware. Delaware was chosen because it is a relatively small state (with only three counties) with publicly available high‐resolution geospatial datasets and with corn as the dominant crop type. We find that the energy use for field operation is the largest energy component for corn production on small farms while the drying process requires the highest energy on medium and large farms. Our results also indicate that producing corn on large and medium farms is more energy‐efficient than on small farms, although small farms consume less electricity and less groundwater for irrigation per unit corn product. Of the three counties in Delaware, Sussex has the highest energy consumption for corn production while Kent has the lowest. On average in Delaware, the corn production requires 42,789 MWh of electricity, 4.2 million gallons of diesel, 1.4 million gallons of gasoline, and 3.1 million gallons of LPG, giving an EFF of 38,171 Btu per corn bushel or 682 Btu/lb. The EFF assessment can inform consumers about the energy inputs of food and provide useful insights for stakeholders and policy makers to develop more sustainable strategies for the food industry. The novelty of this study is to develop a geospatial inventory of EFFs for corn production. Moreover, the proposed methodology is based entirely on public data and is likely generalizable to most other states and crops.
