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Abstract The atmospheric concentration of nitrous oxide (N2O) has increased by 23% since the pre‐industrial era, which substantially destructed the stratospheric ozone layer and changed the global climate. However, it remains uncertain about the reasons behind the increase and the spatiotemporal patterns of soil N2O emissions, a primary biogenic source. Here, we used an integrative land ecosystem model, Dynamic Land Ecosystem Model (DLEM), to quantify direct (i.e., emitted from local soil) and indirect (i.e., emissions related to local practices but occurring elsewhere) N2O emissions in the contiguous United States during 1900–2019. Newly developed geospatial data of land‐use history and crop‐specific agricultural management practices were used to force DLEM at a spatial resolution of 5 arc‐min by 5 arc‐min. The model simulation indicates that the U.S. soil N2O emissions totaled 0.97 ± 0.06 Tg N year−1during the 2010s, with 94% and 6% from direct and indirect emissions, respectively. Hot spots of soil N2O emission are found in the US Corn Belt and Rice Belt. We find a threefold increase in total soil N2O emission in the United States since 1900, 74% of which is from agricultural soil emissions, increasing by 12 times from 0.04 Tg N year−1in the 1900s to 0.51 Tg N year−1in the 2010s. More than 90% of soil N2O emission increase in agricultural soils is attributed to human land‐use change and agricultural management practices, while increases in N deposition and climate warming are the dominant drivers for N2O emission increase from natural soils. Across the cropped acres, corn production stands out with a large amount of fertilizer consumption and high‐emission factors, responsible for nearly two‐thirds of direct agricultural soil N2O emission increase since 1900. Our study suggests a large N2O mitigation potential in cropland and the importance of exploring crop‐specific mitigation strategies and prioritizing management alternatives for targeted crop types.
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Model estimates of water yield and N yield under alternative N management practices across the Mississippi-Atchafalaya River basin during 1980-2017
This dataset contains maps of water yield and nitrogen (N) yield each year, covering the Mississippi/Atchafalaya River Basin (MARB) spanning from 1980 to 2017. These maps were reconstructed by aggregating from a daily model (Dynamic Land Ecosystem Model, DLEM) estimates and are at 5-min×5-min (0.08333° Lat × 0.08333° Lon) resolution. There are two subfolders, "TT" and "DT", within this folder. "TT" and "DT" respectively indicate "traditional timing" and "dynamic timing" of nitrogen fertilizer applications in regards to the model experiments in the main text. The "TT" folder contains the gridded model estimates of water yield (named by "Runoff") and nitrogen yield (named by "Nleach") at annual bases. TT reflects our best estimate of water and N fluxes within the context of multi-factor environmental changes including climate, atmospheric CO2 concentration, N deposition, land use, and human management practices (such as fertilizer use, tillage, tile drainage, etc.). The "DT" folder only contains the model estimates of nitrogen yield (“Nleach”) under an alternative N management practice. More details can be found in the linked publication.
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- Award ID(s):
- 1945036
- PAR ID:
- 10590598
- Publisher / Repository:
- Iowa State University
- Date Published:
- Subject(s) / Keyword(s):
- Environmental Science
- Format(s):
- Medium: X Size: 56053114 Bytes
- Size(s):
- 56053114 Bytes
- Right(s):
- Creative Commons Attribution 4.0 International
- Sponsoring Org:
- National Science Foundation
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