European Commission, Joint Research Centre (JRC), 21027 Ispra, Italy.
Arcadia SIT srl, Vigevano, Italy.
Sci Total Environ. 2024 Dec 1;954:176692. doi: 10.1016/j.scitotenv.2024.176692. Epub 2024 Oct 2.
Contemporary crop production in Europe relies on nitrogen (N) fertilization. Fertilizer prices soared in 2021-2022, and remained at historical high levels in 2023. These high prices invoked an immediate concern on the possible consequences for Europe's food production. In this study, we use a biogeochemical model framework to estimate the impact of reducing mineral N fertilization on crop yields in the European Union (EU). First, crop yields simulated with the biogeochemical DayCent model are evaluated against subnational yield data averaged for 2015-2018 reported by Eurostat and National Statistical Institutes in the EU for soft wheat, barley, grain maize and rapeseed. Then, we simulate three different scenarios where mineral N fertilization across the EU is abruptly reduced by respectively 5, 15 and 25 %, and compare yields to the projected baseline for contemporary conditions (2019-2022). The model evaluation gives r values ranging from 0.28 (rapeseed) to 0.61 (soft wheat) and root mean square errors (RMSE) ranging from 0.6 (rapeseed) to 1.95 t ha (maize). The model shows a reduction in yield per crop at the EU level up to 2.1, 6.4 and 11.2 % with the 5, 15 and 25 % reduction scenario, respectively. Different crops show different percentage reduction in yield following a reduction in mineral N fertilization, showing a legacy effect over the years and depending on the availability of organic fertilizer. The strongest relative yield reduction occurs for soft wheat for all three scenarios. Even with 25 % drop in mineral N fertilization, maize yield in the Netherlands, Belgium and Denmark is not significantly reduced, because of the high N surplus and large share of organic fertilization in these countries. This process-based modelling study provides spatially explicit, high resolution information on the response of crop yields to N fertilizer input reductions, helping policy-makers in decision-making on food security and environmentally-friendly food systems.
当代欧洲的作物生产依赖于氮肥（N）施肥。2021-2022 年肥料价格飙升，并在 2023 年保持在历史高位。这些高价格立即引起了人们对欧洲粮食生产可能产生的后果的关注。在这项研究中，我们使用生物地球化学模型框架来估计减少矿物 N 施肥对欧盟（EU）作物产量的影响。首先，使用生物地球化学 DayCent 模型模拟的作物产量与欧盟各国为软小麦、大麦、谷物玉米和油菜籽在 2015-2018 年报告的由 Eurostat 和国家统计机构平均的国家以下一级产量数据进行评估。然后，我们模拟了三种不同的情景，即在欧盟范围内突然减少矿物 N 施肥量分别为 5%、15%和 25%，并将产量与当代条件（2019-2022 年）的预测基线进行比较。模型评估得出 r 值范围从 0.28（油菜籽）到 0.61（软小麦），均方根误差（RMSE）范围从 0.6（油菜籽）到 1.95 t ha（玉米）。该模型显示，在欧盟层面上，随着 5%、15%和 25%减少方案的实施，每种作物的产量分别减少了 2.1%、6.4%和 11.2%。不同作物在减少矿物 N 施肥后产量减少的百分比不同，这反映了多年来的遗留效应，并取决于有机肥的可用性。对于所有三种情景，软小麦的相对产量降幅最大。即使在矿物 N 施肥减少 25%的情况下，荷兰、比利时和丹麦的玉米产量也不会显著减少，因为这些国家的氮盈余和有机肥的大量使用。这项基于过程的建模研究提供了有关作物产量对 N 肥投入减少的响应的空间明确、高分辨率信息，有助于决策者在粮食安全和环境友好型食品系统方面做出决策。
