Alternative futures of dissolved inorganic nitrogen export from the Mississippi River Basin: influence of crop management, atmospheric deposition, and population growth
| Autor: | Michelle L. McCrackin, Jana E. Compton, Robin L. Dennis, Ellen J. Cooter, John A. Harrison |
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| Rok vydání: | 2018 |
| Předmět: |
010504 meteorology & atmospheric sciences
Land management Sewage 010501 environmental sciences 01 natural sciences Article Bioenergy Environmental protection Environmental Chemistry 0105 earth and related environmental sciences Earth-Surface Processes Water Science and Technology Hydrology Gulf of Mexico Mississippi River Basin business.industry Nutrient management Hypoxia (environmental) Tile drainage Dissolved inorganic nitrogen Agriculture Nitrogen export model Environmental science Sewage treatment business |
| Zdroj: | Biogeochemistry |
| ISSN: | 0168-2563 |
| Popis: | Nitrogen (N) export from the Mississippi River Basin contributes to seasonal hypoxia in the Gulf of Mexico (GOM). We explored monthly dissolved inorganic N (DIN) export to the GOM for a historical year (2002) and two future scenarios (year 2022) by linking macroeonomic energy, agriculture market, air quality, and agriculture land management models to a DIN export model. Future scenarios considered policies aimed at encouraging bioenergy crop production and reducing atmospheric N-emissions, as well as the effect of population growth and the states’ infrastructure plans on sewage fluxes. Model-derived DIN export decreased by about 9% (from 279 to 254 kg N km−2 year−1) between 2002 and 2022 due to a 28% increase in area planted with corn, 24% improvement in crop N-recovery efficiency (NRE, to 0.52), 22% reduction in atmospheric N deposition, and 23% increase in sewage inputs. Changes in atmospheric and sewage inputs had a relatively small effect on DIN export and the effect of bioenergy crop production depended on nutrient management practices. Without improved NRE, increased production of corn would have increased DIN export by about 14% (to 289 kg N km−2 year−1) between 2002 and 2022. Model results suggest that meeting future crop demand while reducing the areal extent of hypoxia could require aggressive actions, such improving basin-level crop NRE to 0.62 or upgrading N-removal capabilities in waste water treatment plants beyond current plans. Tile-drained cropland could contribute up to half of DIN export; thus, practices that reduce N losses from tile drains could also have substantial benefit. |
| Databáze: | OpenAIRE |
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