Institute for Food and Resource Economics, University of Bonn, D-53115 Bonn, Germany.
Institute for Food and Resource Economics, University of Bonn, D-53115 Bonn, Germany.
J Environ Manage. 2018 Jul 1;217:456-467. doi: 10.1016/j.jenvman.2018.03.082. Epub 2018 Apr 6.
The transport of excess manure to crop farming systems is a core measure of livestock farmers to comply with environmental regulations like the EU Nitrates Directive. The German implementation of the directive has recently been revised and will lead to a distinct increase of manure transport. We quantify the environmental impact of 1 m of pig manure excreted in scenarios with and without manure transport by life cycle assessment, focusing on farming systems in North-West Germany. Furthermore, we assess how the environmental impact is linked to the regulation which is causing the transport. Compared to a reference scenario without transport, manure transport lowers all assessed impact categories and no trade-off between environmental impacts is found. Major reductions are realized for global warming (39%), freshwater (61%) and marine eutrophication (54%) as well as particulate matter formation (10%). Furthermore, the depletion of fossil fuels and phosphate is lowered. Reductions are mainly caused by an increase of nutrient use efficiency and the savings in chemical fertilizer. However, in a scenario where manure transport is caused by strict regulations regarding phosphate, needed nitrogen leaves the exporting farm likewise and chemical fertilizer use rises at the exporting farm. Caused by the increased fertilizer use, the positive environmental effect of manure transport diminishes, even leading to a rise of fossil fuel depletion by 20% and slight rise of global warming potential by 3%. However, we find that the use of lorries which combine manure and grain transport and, thereby, reduce empty drives, can prevent this trade-off. Our results show the potential of manure transport to reduce the environmental burden caused by the geographical concentration of livestock production. However, the impact of manure transport on global warming and fossil fuel depletion highly depends on the transport distance. Agronomic measures are needed to prevent the increase of chemical N fertilizer use on the exporting farms and policy makers should be aware of possible trade-offs between strict regulations regarding phosphorus and fossil fuel depletion.
将过多的粪便运送到农作物种植系统是牲畜养殖户遵守环境法规（如欧盟硝酸盐指令）的核心措施。德国最近对该指令的实施进行了修订，这将导致粪便运输量的明显增加。我们通过生命周期评估量化了在有和没有粪便运输的情况下，1 立方米猪粪排泄的环境影响，重点关注德国西北部的农业系统。此外，我们评估了导致运输的法规与环境影响之间的关系。与没有运输的参考情景相比，粪便运输降低了所有评估的影响类别，并且没有发现环境影响之间的权衡。主要减少的是全球变暖（39%）、淡水（61%）和海洋富营养化（54%）以及颗粒物形成（10%）。此外，化石燃料和磷酸盐的消耗也有所降低。减少的主要原因是养分利用效率的提高和化肥的节约。然而，在一个由于磷酸盐的严格法规而导致粪便运输的情景中，同样需要将氮从出口农场带走，并且在出口农场增加化肥的使用。由于化肥使用的增加，粪便运输的积极环境效应减弱，甚至导致化石燃料消耗增加 20%，全球变暖潜力略有增加 3%。然而，我们发现，使用可以同时运输粪便和谷物的卡车，从而减少空驶，就可以避免这种权衡。我们的研究结果表明，粪便运输具有减少由于畜牧业集中而导致的环境负担的潜力。然而，粪便运输对全球变暖的影响和对化石燃料消耗的影响高度取决于运输距离。需要采取农业措施来防止出口农场增加化学 N 肥料的使用，政策制定者应该意识到严格的磷法规和化石燃料消耗之间可能存在的权衡。
