Biodiesel is increasingly used as a fuel in transportation. It is generally considered an environmentally friendly alternative for diesel from fossil oil, because of lower emissions of the greenhouse gas carbon dioxide (CO₂). However, nitrous oxide (N₂O) emissions during the growth of energy crops can be considerable. N₂O is emitted as a result of fertiliser use, needed to cultivate the energy crops. Fertiliser use not only increases the direct agricultural soil emissions, but also the indirect N₂O emissions from aquatic systems, after leaching and runoff of nitrogen from fertilised soils. The aim of this study is to quantify future N₂O emissions associated with the cultivation of energy crops in European river basins. We analyse three future scenarios for biodiesel production in Europe, and the associated N₂O emissions from fertilised fields. Our focus is on biodiesel produced from first generation energy crops. The scenarios assume that by the year 2050, 15–30% of the demand for fossil diesel is replaced by biodiesel. This would change the European fertiliser needs and, as a result, N₂O emissions from fertilised soils. Our results indicate that increased biodiesel production may increase N₂O emissions in Europe by about 25–45% relative to a scenario without a growth in biodiesel production, but not equally in all regions and all scenarios. The rate of change depends on where energy crops are grown, and whether or not they replace agricultural crops, or natural vegetation.

生物柴油越来越多地用作运输中的燃料。由于减少了温室气体二氧化碳（CO ₂）的排放，通常被认为是化石柴油中的一种环保替代品。但是，能源作物生长期间的一氧化二氮（N ₂ O）排放可能会很大。由于肥料的使用而排放出N ₂ O，这是种植能源作物所需的。化肥的使用不仅增加了农业土壤的直接排放量，而且还增加了氮从土壤中的淋失和流失后，水生系统间接产生的N ₂ O排放量。这项研究的目的是量化未来的N ₂与欧洲河流域能源作物种植相关的O排放。我们分析了欧洲生物柴油生产的三种未来情况，以及受精田地相关的N ₂ O排放。我们的重点是使用第一代能源作物生产的生物柴油。这些情景假设到2050年，对化石柴油的需求的15％至30％将被生物柴油替代。这将改变欧洲对肥料的需求，从而改变施肥土壤中的N ₂ O排放量。我们的结果表明，增加生物柴油产量可能会增加N ₂与没有生物柴油产量增长的情景相比，欧洲的O排放量约占25-45％，但在所有地区和所有情景中均不相同。变化的速度取决于能源作物的种植地，以及它们是否替代农业作物或自然植被。