Contrasting Carbon and Water Flux Dynamics in an East African Rangeland and Cropland.
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| Title: | Contrasting Carbon and Water Flux Dynamics in an East African Rangeland and Cropland. |
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| Authors: | Odongo, Vincent1 (AUTHOR) v.odongo@cgiar.org, Leitner, Sonja M.1 (AUTHOR), Dowling, Thomas P. F.2,3 (AUTHOR), Gluecks, Ilona4 (AUTHOR), Jackowicz‐Korczynski, Marcin5 (AUTHOR), Rinne, Janne5,6 (AUTHOR), Wooster, Martin J.2 (AUTHOR), Merbold, Lutz1,7 (AUTHOR) |
| Source: | Journal of Geophysical Research. Biogeosciences. Oct2025, Vol. 130 Issue 10, p1-21. 21p. |
| Subject Terms: | *Rangelands, *Carbon cycle, *Land management, *Climate change, *Farms, *Savannas, Ecological resilience, Water vapor transport |
| Geographic Terms: | East Africa |
| Abstract: | This study examines carbon (C) and water dynamics in two East African dryland ecosystems: a savanna rangeland grazed by livestock and wildlife, and a rainfed cropland under minimal tillage. Over 185 days, both systems were showed a similar magnitude of C emissions with differing temporal patterns. The rangeland showed fluctuating C exchange, with losses followed by increased C uptake after rainfall events. The cropland initially acted as a C sink, and when lateral C export from chickpea harvest were accounted for, the overall C balance shifted to a net source. Cropland demonstrated higher carbon use efficiency (CUE), driven by efficient C allocation for crop growth, supported by fertilizers, pesticides, and minimum tillage practices. During the peak growing period, cropland also had greater water use efficiency (WUE) likely reflecting optimized agricultural management under favorable moisture conditions. However, over the entire period, WUE was significantly higher in the rangeland than in the cropland (p > 0.05) possibly due to more consistent vegetation cover and adaptive traits that minimize water loss. The cropland showed a complex relationship between WUE and CUE, where increased productivity also simultaneously drove higher respiration rates. Our findings, particularly the shift in cropland carbon balance following harvest emphasize the importance of including lateral C fluxes and intra‐annual variations in C balance assessments for accurate budgeting. Both ecosystems were co‐limited by water and nitrogen, with plant adaptations to drought and dry spells, including efficient water use and sustained photosynthesis under moisture stress playing a critical role in maintaining ecosystem CUE. Sustainable land management strategies that account for the interactions between C and water dynamics, biodiversity, and ecosystem functioning are vital to enhancing C storage, mitigating climate change, and improving resilience in rangelands and croplands. Plain Language Summary: East Africa's drylands are vital ecosystems, but how do they balance carbon and water under the dry environmental conditions? Our study sheds light on two such ecosystems: a savanna rangeland grazed by livestock and wildlife, and a cropland managed with minimal soil disturbance. Over 6 months, we discovered that both ecosystems gained and lost about the same amount of carbon overall. However, they did so in different ways: The rangeland's carbon levels fluctuated, with losses during dry spells and gains after rain, reflecting its long‐term adaptation to semi‐arid conditions. Meanwhile, the cropland initially acted as a carbon sink, but when we factored in the carbon removed during harvest, it balanced out. The cropland was also better at using carbon and water efficiently during the growing season, thanks to farming practices like fertilizer use and pest control. Our findings highlight the delicate balance between carbon and water in these ecosystems, shaped by rainfall, nutrients, and management practices. Understanding these dynamics is crucial for improving land management strategies that protect biodiversity, enhance carbon storage, and build resilience against climate change. Key Points: Accounting for lateral carbon export from chickpea harvest adjusted the net carbon balance of cropland to near neutralRespiration in the rangeland was decoupled from increasing GPP likely due to nutrient limitations and water‐conserving plant adaptationsRangelands conserve water at the expense of biomass, reducing water use efficiency during water‐abundant periods like the growing season [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Geophysical Research. Biogeosciences is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
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| Items | – Name: Title Label: Title Group: Ti Data: Contrasting Carbon and Water Flux Dynamics in an East African Rangeland and Cropland. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Odongo%2C+Vincent%22">Odongo, Vincent</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> v.odongo@cgiar.org</i><br /><searchLink fieldCode="AR" term="%22Leitner%2C+Sonja+M%2E%22">Leitner, Sonja M.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Dowling%2C+Thomas+P%2E+F%2E%22">Dowling, Thomas P. F.</searchLink><relatesTo>2,3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Gluecks%2C+Ilona%22">Gluecks, Ilona</searchLink><relatesTo>4</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Jackowicz‐Korczynski%2C+Marcin%22">Jackowicz‐Korczynski, Marcin</searchLink><relatesTo>5</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Rinne%2C+Janne%22">Rinne, Janne</searchLink><relatesTo>5,6</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Wooster%2C+Martin+J%2E%22">Wooster, Martin J.</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Merbold%2C+Lutz%22">Merbold, Lutz</searchLink><relatesTo>1,7</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Geophysical+Research%2E+Biogeosciences%22">Journal of Geophysical Research. Biogeosciences</searchLink>. Oct2025, Vol. 130 Issue 10, p1-21. 21p. – Name: Subject Label: Subject Terms Group: Su Data: *<searchLink fieldCode="DE" term="%22Rangelands%22">Rangelands</searchLink><br />*<searchLink fieldCode="DE" term="%22Carbon+cycle%22">Carbon cycle</searchLink><br />*<searchLink fieldCode="DE" term="%22Land+management%22">Land management</searchLink><br />*<searchLink fieldCode="DE" term="%22Climate+change%22">Climate change</searchLink><br />*<searchLink fieldCode="DE" term="%22Farms%22">Farms</searchLink><br />*<searchLink fieldCode="DE" term="%22Savannas%22">Savannas</searchLink><br /><searchLink fieldCode="DE" term="%22Ecological+resilience%22">Ecological resilience</searchLink><br /><searchLink fieldCode="DE" term="%22Water+vapor+transport%22">Water vapor transport</searchLink> – Name: SubjectGeographic Label: Geographic Terms Group: Su Data: <searchLink fieldCode="DE" term="%22East+Africa%22">East Africa</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: This study examines carbon (C) and water dynamics in two East African dryland ecosystems: a savanna rangeland grazed by livestock and wildlife, and a rainfed cropland under minimal tillage. Over 185 days, both systems were showed a similar magnitude of C emissions with differing temporal patterns. The rangeland showed fluctuating C exchange, with losses followed by increased C uptake after rainfall events. The cropland initially acted as a C sink, and when lateral C export from chickpea harvest were accounted for, the overall C balance shifted to a net source. Cropland demonstrated higher carbon use efficiency (CUE), driven by efficient C allocation for crop growth, supported by fertilizers, pesticides, and minimum tillage practices. During the peak growing period, cropland also had greater water use efficiency (WUE) likely reflecting optimized agricultural management under favorable moisture conditions. However, over the entire period, WUE was significantly higher in the rangeland than in the cropland (p > 0.05) possibly due to more consistent vegetation cover and adaptive traits that minimize water loss. The cropland showed a complex relationship between WUE and CUE, where increased productivity also simultaneously drove higher respiration rates. Our findings, particularly the shift in cropland carbon balance following harvest emphasize the importance of including lateral C fluxes and intra‐annual variations in C balance assessments for accurate budgeting. Both ecosystems were co‐limited by water and nitrogen, with plant adaptations to drought and dry spells, including efficient water use and sustained photosynthesis under moisture stress playing a critical role in maintaining ecosystem CUE. Sustainable land management strategies that account for the interactions between C and water dynamics, biodiversity, and ecosystem functioning are vital to enhancing C storage, mitigating climate change, and improving resilience in rangelands and croplands. Plain Language Summary: East Africa's drylands are vital ecosystems, but how do they balance carbon and water under the dry environmental conditions? Our study sheds light on two such ecosystems: a savanna rangeland grazed by livestock and wildlife, and a cropland managed with minimal soil disturbance. Over 6 months, we discovered that both ecosystems gained and lost about the same amount of carbon overall. However, they did so in different ways: The rangeland's carbon levels fluctuated, with losses during dry spells and gains after rain, reflecting its long‐term adaptation to semi‐arid conditions. Meanwhile, the cropland initially acted as a carbon sink, but when we factored in the carbon removed during harvest, it balanced out. The cropland was also better at using carbon and water efficiently during the growing season, thanks to farming practices like fertilizer use and pest control. Our findings highlight the delicate balance between carbon and water in these ecosystems, shaped by rainfall, nutrients, and management practices. Understanding these dynamics is crucial for improving land management strategies that protect biodiversity, enhance carbon storage, and build resilience against climate change. Key Points: Accounting for lateral carbon export from chickpea harvest adjusted the net carbon balance of cropland to near neutralRespiration in the rangeland was decoupled from increasing GPP likely due to nutrient limitations and water‐conserving plant adaptationsRangelands conserve water at the expense of biomass, reducing water use efficiency during water‐abundant periods like the growing season [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Geophysical Research. Biogeosciences is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1029/2024JG008623 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 21 StartPage: 1 Subjects: – SubjectFull: Rangelands Type: general – SubjectFull: Carbon cycle Type: general – SubjectFull: Land management Type: general – SubjectFull: Climate change Type: general – SubjectFull: Farms Type: general – SubjectFull: Savannas Type: general – SubjectFull: Ecological resilience Type: general – SubjectFull: Water vapor transport Type: general – SubjectFull: East Africa Type: general Titles: – TitleFull: Contrasting Carbon and Water Flux Dynamics in an East African Rangeland and Cropland. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Odongo, Vincent – PersonEntity: Name: NameFull: Leitner, Sonja M. – PersonEntity: Name: NameFull: Dowling, Thomas P. F. – PersonEntity: Name: NameFull: Gluecks, Ilona – PersonEntity: Name: NameFull: Jackowicz‐Korczynski, Marcin – PersonEntity: Name: NameFull: Rinne, Janne – PersonEntity: Name: NameFull: Wooster, Martin J. – PersonEntity: Name: NameFull: Merbold, Lutz IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 10 Text: Oct2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 21698953 Numbering: – Type: volume Value: 130 – Type: issue Value: 10 Titles: – TitleFull: Journal of Geophysical Research. Biogeosciences Type: main |
| ResultId | 1 |
