Wageningen University and Research, Environmental Research, PO Box 47, 6700 AA Wageningen, the Netherlands; Wageningen University and Research, Environmental Systems Analysis Group, PO Box 47, 6700 AA Wageningen, the Netherlands.
Wageningen University and Research, Environmental Systems Analysis Group, PO Box 47, 6700 AA Wageningen, the Netherlands.
Sci Total Environ. 2021 Sep 10;786:147283. doi: 10.1016/j.scitotenv.2021.147283. Epub 2021 Apr 23.
Agricultural production in the EU has increased strongly since the 1940s, partly driven by increased nitrogen (N) fertiliser and manure inputs. Increased N inputs and associated losses, however, adversely affect air and water quality, with widespread impacts on terrestrial and aquatic ecosystems and human health. Managing these impacts requires knowledge on 'safe boundaries' for N inputs, i.e., N flows that do not exceed environmental thresholds. We used a spatially explicit N balance model for the EU to derive boundaries for N losses and associated N inputs for three environmental thresholds: (i) N deposition onto natural areas to protect terrestrial biodiversity (critical N loads), (ii) N concentration in runoff to surface water (2.5 mg N l) to protect aquatic ecosystems and (iii) nitrate (NO) concentration in leachate to groundwater (50 mg NO l) to meet the EU drinking water standard. Critical N losses and inputs were calculated for ~40,000 unique soil-slope-climate combinations and then aggregated at country- and EU-level. To respect thresholds for N deposition, N inputs in the EU need to be reduced by 31% on average, ranging from 0% in several countries to 59% in Ireland and Denmark. The strongest reductions are required in intensive livestock regions, such as Benelux, Brittany and the Po valley. To respect thresholds for N concentration in runoff to surface water, N inputs need to be reduced by 43% on average, ranging from 2% in Estonia to 74% in the Netherlands. Average critical N inputs in view of the threshold for NO concentration in leachate to groundwater are close to actual (year 2010) inputs, even though leaching thresholds are exceeded in 18% of agricultural land. Critical N inputs and their exceedances presented in this paper can inform more targeted mitigation policies than flat-rate targets for N loss reductions currently mentioned in EU policies.
自 20 世纪 40 年代以来，欧盟的农业生产大幅增长，部分原因是增加了氮（N）肥料和粪肥的投入。然而，增加的 N 投入和相关的损失会对空气和水质产生不利影响，对陆地和水生生态系统以及人类健康产生广泛影响。管理这些影响需要了解 N 投入的“安全界限”，即不会超过环境阈值的 N 流动。我们使用欧盟的空间明确 N 平衡模型来推导三个环境阈值的 N 损失和相关 N 投入的边界：（i）N 沉积到自然区域以保护陆地生物多样性（临界 N 负荷），（ii）地表水中 N 浓度（2.5 mg N l）以保护水生生态系统，（iii）地下水硝酸盐（NO）浓度（50 mg NO l）以满足欧盟饮用水标准。对约 40000 个独特的土壤-坡度-气候组合进行了临界 N 损失和投入的计算，然后在国家和欧盟层面进行了汇总。为了遵守 N 沉积的阈值，欧盟的 N 投入需要平均减少 31%，从几个国家的 0%到爱尔兰和丹麦的 59%不等。集约化畜牧业地区，如比荷卢经济联盟、布列塔尼和波河谷地区，需要最大程度地减少 N 投入。为了遵守地表水中 N 浓度的阈值，N 投入需要平均减少 43%，从爱沙尼亚的 2%到荷兰的 74%不等。鉴于地下水硝酸盐浓度的阈值，平均临界 N 投入接近实际（2010 年）投入，尽管在 18%的农业用地上已经超过了淋溶阈值。本文介绍的临界 N 投入及其超标情况，可以为更有针对性的缓解政策提供信息，而不是目前欧盟政策中提到的针对 N 损失减少的统一目标。
