Abstract
This study evaluated soil–atmosphere greenhouse gas (GHG) fluxes—including carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)—in cacao agroecosystems on São Tomé Island, Central Africa. The field campaign was conducted between April and May 2025, coinciding with the transition from the short rainy season to the onset of the dry period. The sampling design comprised two system types (biodiverse and conventional), two crop development stages (growing and productive), and two climatic zones (wet and dry). Gas fluxes were measured using the static chamber method and analyzed in relation to climatic, topographic, and edaphic variables. CO2 fluxes were the dominant contributor to total emissions, accounting for approximately 97.4% of the global warming potential (GWP), while CH4 and N2O together contributed less than 3%. The highest CO2 emissions occurred in conventional systems during the growing stage in the wet zone (125.5 ± 11.41 mg C m−2 h−1). CH4 generally acted as a sink, particularly in conventional systems in the dry zone (−12.58 ± 2.35 μg C m−2 h−1), although net emissions were detected in biodiverse systems in the wet zone (5.08 ± 1.50 μg C m−2 h−1). The highest N2O fluxes were observed in conventional growing systems (32.28 ± 5.76 μg N m−2 h−1). GHG dynamics were mainly regulated by climatic factors—such as air temperature, relative humidity, and precipitation—and by key edaphic properties, including soil pH, soil organic carbon, soil temperature, and clay content. Projected GWP values ranged from 9.05 ± 2.77 to 40.9 ± 6.23 Mg CO2-eq ha−1 year−1, with the highest values recorded in conventional systems in the growing stage. Overall, our findings underscore the potential of biodiversity-based agroforestry as a climate-smart practice to mitigate net GHG emissions in tropical cacao landscapes.
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Claims 9
Claim · model-written summary
CO2 accounted for about 97.4% of global warming potential.
- Taxon
- cacao
Theobroma cacaot0 - Outcome
- global warming potential (GWP)e0
- Direction
- dominante0
- Value
- 97.4%e0
- Setting
- São Tomé Island, Central Africat0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CO2 fluxes were the dominant contributor to total emissions, accounting for approximately 97.4% of the global warming potential (GWP), while CH4 and N2O together contributed less than 3%.”
t0“Cacao Agroecosystems on São Tomé Island, Central Africa”
Claim · model-written summary
CH4 and N2O together contributed less than 3% of global warming potential.
- Taxon
- cacaoTheobroma cacaot0
- Outcome
- CH4 and N2Oe0
- Direction
- less thane0
- Value
- less than 3%e0
- Setting
- São Tomé Island, Central Africat0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CO2 fluxes were the dominant contributor to total emissions, accounting for approximately 97.4% of the global warming potential (GWP), while CH4 and N2O together contributed less than 3%.”
t0“Cacao Agroecosystems on São Tomé Island, Central Africa”
Claim · model-written summary
The highest CO2 emissions were 125.5 ± 11.41 mg C m−2 h−1 in conventional growing systems in the wet zone.
- Taxon
- cacaoTheobroma cacaot0
- Outcome
- CO2 emissionse0
- Direction
- higheste0
- Value
- 125.5 ± 11.41 mg C m−2 h−1e0
- Qualifier
- conventional systems during the growing stage in the wet zonee0
- Setting
- São Tomé Island, Central Africat0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest CO2 emissions occurred in conventional systems during the growing stage in the wet zone (125.5 ± 11.41 mg C m−2 h−1).”
t0“Cacao Agroecosystems on São Tomé Island, Central Africa”
Claim · model-written summary
CH4 generally acted as a sink, particularly in conventional systems in the dry zone.
- Taxon
- cacaoTheobroma cacaot0
- Outcome
- CH4 generally acted as a sinke0
- Value
- −12.58 ± 2.35 μg C m−2 h−1e0
- Qualifier
- conventional systems in the dry zonee0
- Setting
- São Tomé Island, Central Africat0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CH4 generally acted as a sink, particularly in conventional systems in the dry zone (−12.58 ± 2.35 μg C m−2 h−1), although net emissions were detected in biodiverse systems in the wet zone (5.08 ± 1.50 μg C m−2 h−1).”
t0“Cacao Agroecosystems on São Tomé Island, Central Africa”
Claim · model-written summary
CH4 net emissions of 5.08 ± 1.50 μg C m−2 h−1 occurred in biodiverse systems in the wet zone.
- Taxon
- cacaoTheobroma cacaot0
- Outcome
- net emissionse0
- Value
- 5.08 ± 1.50 μg C m−2 h−1e0
- Qualifier
- biodiverse systems in the wet zonee0
- Setting
- São Tomé Island, Central Africat0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CH4 generally acted as a sink, particularly in conventional systems in the dry zone (−12.58 ± 2.35 μg C m−2 h−1), although net emissions were detected in biodiverse systems in the wet zone (5.08 ± 1.50 μg C m−2 h−1).”
t0“Cacao Agroecosystems on São Tomé Island, Central Africa”
Claim · model-written summary
N2O fluxes were highest in conventional growing systems at 32.28 ± 5.76 μg N m−2 h−1.
- Taxon
- cacaoTheobroma cacaot0
- Outcome
- N2O fluxese0
- Direction
- higheste0
- Value
- 32.28 ± 5.76 μg N m−2 h−1e0
- Qualifier
- conventional growing systemse0
- Setting
- São Tomé Island, Central Africat0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest N2O fluxes were observed in conventional growing systems (32.28 ± 5.76 μg N m−2 h−1).”
t0“Cacao Agroecosystems on São Tomé Island, Central Africa”
Claim · model-written summary
GHG dynamics were associated mainly with climate and soil properties.
- Taxon
- cacaoTheobroma cacaot0
- Outcome
- GHG dynamicse0
- Qualifier
- climatic factorse0
- Setting
- São Tomé Island, Central Africat0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“GHG dynamics were mainly regulated by climatic factors—such as air temperature, relative humidity, and precipitation—and by key edaphic properties, including soil pH, soil organic carbon, soil temperature, and clay content.”
t0“Cacao Agroecosystems on São Tomé Island, Central Africa”
Claim · model-written summary
Projected GWP ranged from 9.05 ± 2.77 to 40.9 ± 6.23 Mg CO2-eq ha−1 year−1.
- Taxon
- cacaoTheobroma cacaot0
- Outcome
- GWP valuese0
- Value
- 9.05 ± 2.77 to 40.9 ± 6.23 Mg CO2-eq ha−1 year−1e0
- Qualifier
- conventional systems in the growing stagee0
- Setting
- São Tomé Island, Central Africat0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Projected GWP values ranged from 9.05 ± 2.77 to 40.9 ± 6.23 Mg CO2-eq ha−1 year−1, with the highest values recorded in conventional systems in the growing stage.”
t0“Cacao Agroecosystems on São Tomé Island, Central Africa”
Claim · model-written summary
Biodiversity-based agroforestry was identified as a potential climate-smart practice for reducing net GHG emissions.
- Taxon
- cacaoTheobroma cacaot0
- Outcome
- biodiversity-based agroforestry as a climate-smart practice to mitigate net GHG emissionse0
- Setting
- São Tomé Island, Central Africat0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“our findings underscore the potential of biodiversity-based agroforestry as a climate-smart practice to mitigate net GHG emissions in tropical cacao landscapes.”
t0“Cacao Agroecosystems on São Tomé Island, Central Africa”