Net greenhouse gas balance in U.S. croplands : How can soils be part of the climate solution?

© 2023 The Authors. Global Change Biology published by John Wiley & Sons Ltd..

Agricultural soils play a dual role in regulating the Earth's climate by releasing or sequestering carbon dioxide (CO2 ) in soil organic carbon (SOC) and emitting non-CO2 greenhouse gases (GHGs) such as nitrous oxide (N2 O) and methane (CH4 ). To understand how agricultural soils can play a role in climate solutions requires a comprehensive assessment of net soil GHG balance (i.e., sum of SOC-sequestered CO2 and non-CO2 GHG emissions) and the underlying controls. Herein, we used a model-data integration approach to understand and quantify how natural and anthropogenic factors have affected the magnitude and spatiotemporal variations of the net soil GHG balance in U.S. croplands during 1960-2018. Specifically, we used the dynamic land ecosystem model for regional simulations and used field observations of SOC sequestration rates and N2 O and CH4 emissions to calibrate, validate, and corroborate model simulations. Results show that U.S. agricultural soils sequestered 13.2 ± 1.16 $$ 13.2\pm 1.16 $$ Tg CO2 -C year-1 in SOC (at a depth of 3.5 m) during 1960-2018 and emitted 0.39 ± 0.02 $$ 0.39\pm 0.02 $$ Tg N2 O-N year-1 and 0.21 ± 0.01 $$ 0.21\pm 0.01 $$ Tg CH4 -C year-1 , respectively. Based on the GWP100 metric (global warming potential on a 100-year time horizon), the estimated national net GHG emission rate from agricultural soils was 122.3 ± 11.46 $$ 122.3\pm 11.46 $$ Tg CO2 -eq year-1 , with the largest contribution from N2 O emissions. The sequestered SOC offset ~28% of the climate-warming effects resulting from non-CO2 GHG emissions, and this offsetting effect increased over time. Increased nitrogen fertilizer use was the dominant factor contributing to the increase in net GHG emissions during 1960-2018, explaining ~47% of total changes. In contrast, reduced cropland area, the adoption of agricultural conservation practices (e.g., reduced tillage), and rising atmospheric CO2 levels attenuated net GHG emissions from U.S. croplands. Improving management practices to mitigate N2 O emissions represents the biggest opportunity for achieving net-zero emissions in U.S. croplands. Our study highlights the importance of concurrently quantifying SOC-sequestered CO2 and non-CO2 GHG emissions for developing effective agricultural climate change mitigation measures.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:30

Enthalten in:

Global change biology - 30(2024), 1 vom: 04. Jan., Seite e17109

Sprache:

Englisch

Beteiligte Personen:

You, Yongfa [VerfasserIn]
Tian, Hanqin [VerfasserIn]
Pan, Shufen [VerfasserIn]
Shi, Hao [VerfasserIn]
Lu, Chaoqun [VerfasserIn]
Batchelor, William D [VerfasserIn]
Cheng, Bo [VerfasserIn]
Hui, Dafeng [VerfasserIn]
Kicklighter, David [VerfasserIn]
Liang, Xin-Zhong [VerfasserIn]
Li, Xiaoyong [VerfasserIn]
Melillo, Jerry [VerfasserIn]
Pan, Naiqing [VerfasserIn]
Prior, Stephen A [VerfasserIn]
Reilly, John [VerfasserIn]

Links:

Volltext

Themen:

142M471B3J
7440-44-0
Agricultural management practices
Carbon
Carbon Dioxide
DLEM
Greenhouse Gases
Greenhouse gas balance
Journal Article
K50XQU1029
Methane
Nitrous Oxide
Nitrous oxide
OP0UW79H66
SOC sequestration
Soil
U.S. croplands

Anmerkungen:

Date Completed 29.01.2024

Date Revised 29.01.2024

published: Print

Citation Status MEDLINE

doi:

10.1111/gcb.17109

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM367639637