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Abstract The large areal extent of hypoxia in the northern Gulf of Mexico has been partially attributed to substantial nitrogen (N) loading from the Mississippi River basin, which is driven by multiple natural and human factors. The available water quality monitoring data and most of the current models are insufficient to fully quantify N load magnitude and the underlying controls. Here we use a process‐based Dynamic Land Ecosystem Model to examine how multiple factors (synthetic N fertilizer, atmospheric N deposition, land use changes, climate variability, and increasing atmospheric CO2) have affected the loading and delivery of total nitrogen (TN) consisting of ammonium and nitrate (dissolved inorganic N) and total organic nitrogen from the Mississippi River basin during 1901–2014. The model results indicate that TN export during 2000–2014 was twofold larger than that in the first decade of twentieth century: Dissolved inorganic N export increased by 140% dominated by nitrate; total organic nitrogen export increased by 53%. The substantial enrichment of TN export since the 1960s was strongly associated with increased anthropogenic N inputs (synthetic N fertilizer and atmospheric N deposition). The greatest export of TN was in the spring. Although the implementation of N reduction has been carried out over the past three decades, total N loads to the northern Gulf of Mexico have not decreased significantly. Due to the legacy effect from historical N accumulation in soils and riverbeds, a larger reduction in synthetic N fertilizer inputs as well as improved N management practices are needed to alleviate ocean hypoxia in the northern Gulf of Mexico.
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Scenario analysis of nitrogen surplus typologies in Europe shows that a 20% fertilizer reduction may fall short of 2030 EU Green Deal goals
Abstract The Farm to Fork (F2F) Strategy under the Green Deal aims to halve nutrient losses by 2030 in the European Union (EU). Here, using the nitrogen surplus as an indicator for nitrogen losses in agricultural areas, we explore a range of scenarios for nitrogen surplus reduction across EU landscapes. We identify four nitrogen surplus typologies, each responding differently to input reduction. A 20% decrease in synthetic fertilizer alone is projected to reduce the nitrogen surplus by only 10–16%, falling short of F2F goals. Specific top-down scenarios such as reducing synthetic fertilizer by 43% and animal manure by 4%, coupled with improved technological and management practices, can achieve a reduction of up to 30–45% in nitrogen surplus. Among the most ambitious scenarios, only a handful of EU countries (four to five) may meet the intended F2F nitrogen pollution targets. Achieving F2F goals requires region-specific strategies to reduce nitrogen use while improving efficiency and sustaining productivity.
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- Award ID(s):
- 2330502
- PAR ID:
- 10629022
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Food
- Volume:
- 6
- Issue:
- 8
- ISSN:
- 2662-1355
- Format(s):
- Medium: X Size: p. 787-798
- Size(s):
- p. 787-798
- Sponsoring Org:
- National Science Foundation
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