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You Y, Tian H, Pan S, Shi H, Lu C, Batchelor WD, Cheng B, Hui D, Kicklighter D, Liang XZ, Li X, Melillo J, Pan N, Prior SA, Reilly J. Net greenhouse gas balance in U.S. croplands: How can soils be part of the climate solution? Glob Chang Biol 2024; 30:e17109. [PMID: 38273550 DOI: 10.1111/gcb.17109] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 11/22/2023] [Accepted: 12/01/2023] [Indexed: 01/27/2024]
Abstract
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 sequestered13.2 ± 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 emitted0.39 ± 0.02 $$ 0.39\pm 0.02 $$ Tg N2 O-N year-1 and0.21 ± 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 was122.3 ± 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.
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Affiliation(s)
- Yongfa You
- Center for Earth System Science and Global Sustainability (CES3), Schiller Institute for Integrated Science and Society, Boston College, Chestnut Hill, Massachusetts, USA
- Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, Massachusetts, USA
- College of Forestry, Wildlife and Environment, Auburn University, Auburn, Alabama, USA
| | - Hanqin Tian
- Center for Earth System Science and Global Sustainability (CES3), Schiller Institute for Integrated Science and Society, Boston College, Chestnut Hill, Massachusetts, USA
- Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, Massachusetts, USA
| | - Shufen Pan
- Center for Earth System Science and Global Sustainability (CES3), Schiller Institute for Integrated Science and Society, Boston College, Chestnut Hill, Massachusetts, USA
- College of Forestry, Wildlife and Environment, Auburn University, Auburn, Alabama, USA
- Department of Engineering, Boston College, Chestnut Hill, Massachusetts, USA
| | - Hao Shi
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Chaoqun Lu
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
| | | | - Bo Cheng
- Biosystems Engineering Department, Auburn University, Auburn, Alabama, USA
| | - Dafeng Hui
- Department of Biological Sciences, Tennessee State University, Nashville, Tennessee, USA
| | - David Kicklighter
- The Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Xin-Zhong Liang
- Department of Atmospheric and Oceanic Science and Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland, USA
| | - Xiaoyong Li
- Center for Earth System Science and Global Sustainability (CES3), Schiller Institute for Integrated Science and Society, Boston College, Chestnut Hill, Massachusetts, USA
- Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, Massachusetts, USA
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Jerry Melillo
- The Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Naiqing Pan
- Center for Earth System Science and Global Sustainability (CES3), Schiller Institute for Integrated Science and Society, Boston College, Chestnut Hill, Massachusetts, USA
- Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, Massachusetts, USA
| | - Stephen A Prior
- USDA-ARS National Soil Dynamics Laboratory, Auburn, Alabama, USA
| | - John Reilly
- Joint Program on the Science and Policy of Global Change, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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