Potsdam Institute for Climate Impact Research (PIK), 14473, Potsdam, Germany.
Laboratoire des Sciences du Climat et de l'Environnement, Institut Pierre-Simon Laplace (IPSL), 91191, Gif sur Yvette, France.
Sci Rep. 2018 Nov 15;8(1):16865. doi: 10.1038/s41598-018-35351-1.
France is a major crop producer, with a production share of approx. 20% within the European Union. Yet, a discussion has recently started whether French yields are stagnating. While for wheat previous results are unanimously pointing to recent stagnation, there is contradictory evidence for maize and few to no results for other crops. Here we analyse a data set with more than 120,000 yield observations from 1900 to 2016 for ten crops (barley, durum and soft wheat, maize, oats, potatoes, rapeseed, sugar beet, sunflower and wine) in the 96 mainland French départements (NUTS3 administrative division). We dissect the evolution of yield trends over time and space, analyse yield variation and evaluate whether growth of yields has stalled in recent years. Yields have, on average across crops, multiplied four-fold over the course of the 20 century. While absolute yield variability has increased, the variation relative to the mean has halved - mean yields have increased faster than their variability. But growth of yields has stagnated since the 1990's for winter wheat, barley, oats, durum wheat, sunflower and wine on at least 25% of their areas. Reaching yield potentials is unlikely as a cause for stagnation. Maize, in contrast, shows no evidence for stagnation.
法国是主要的农作物生产国，其在欧盟的产量份额约为 20%。然而，最近人们开始讨论法国的产量是否停滞不前。尽管对于小麦，之前的结果一致表明近期产量停滞不前，但对于玉米则存在相互矛盾的证据，而对于其他作物则几乎没有结果。在这里，我们分析了一个包含 1900 年至 2016 年 12 万多个产量观测值的数据组，涉及 10 种作物（大麦、硬质小麦和软质小麦、玉米、燕麦、土豆、油菜籽、甜菜、向日葵和葡萄酒）在法国 96 个大陆省份（NUTS3 行政分区）。我们剖析了随时间和空间演变的产量趋势，分析了产量变化，并评估了近年来产量增长是否停滞不前。在 20 世纪的过程中，平均而言，所有作物的产量都增加了四倍。虽然绝对产量波动性有所增加，但相对于平均值的波动性却减半——平均产量的增长速度快于其波动性。但是，自 20 世纪 90 年代以来，在至少 25%的冬小麦、大麦、燕麦、硬质小麦、向日葵和葡萄酒种植面积上，冬季小麦、大麦、燕麦、硬质小麦、向日葵和葡萄酒的产量增长已经停滞不前。达到产量潜力不太可能是导致停滞的原因。相比之下，玉米没有停滞的迹象。
