Abstract
In recent years, numerous aquaculture ponds in southeast China have been transformed into rice paddies or rice–shrimp fields. This shift in land use can potentially alter the biogeochemical cycling of carbon and nitrogen, thereby influencing CH4 and N2O emissions. However, the exact impacts and factors driving these changes remain unclear. Herein, a two-year field experiment was conducted to evaluate and compare CH4 and N2O emissions from shrimp ponds (SP), alongside reclaimed rice monoculture (RM) and rice–shrimp coculture (RS) fields that were converted from shrimp ponds. The findings showed that converting aquacultural wetlands to RM significantly increased annual emissions, with CH4 rising dramatically from 103 to 490 kg/(ha·yr) (a 375.7% increase) and N2O increasing from 4.22 to 7.39 kg/(ha·yr) (a 75.1% increase). However, further converting RM into RS notably reduced annual emissions, with CH4 decreasing from 490 to 189 kg/(ha·yr) and N2O from 7.39 to 4.32 kg/(ha·yr), corresponding to reductions of 61.4% and 41.5%, respectively. This agricultural land use change significantly impacted the reliance of CH4 and N2O fluxes on both biotic and abiotic variables across the three wetland systems, stemming from diverse agricultural practices. Furthermore, the scaled global warming potential (SGWP) and net ecosystem economic profit (NEEP)-SGWP of RM (24.1 t CO2-eq/(ha·yr) and 125 kg CO2-eq per $/(ha·yr)) were obviously higher than those of RS (9.66 t CO2-eq/(ha·yr) and 4.76 kg CO2-eq $/(ha·yr)) and SP (5.78 t CO2-eq/(ha·yr) and 1.1 kg CO2-eq per $/(ha·yr)), respectively. The results highlight that the conversion of aquaculture SP to RM and further to RS coculture can drastically reduce greenhouse gas emissions while enhancing economic benefits, thereby addressing environmental and profitability issues arising from the reclamation of SP.
Similar content being viewed by others
Carbon sequestration, emission reduction, and technical strategies of rice-crayfish farming in central China
Co-benefits for net carbon emissions and rice yields through improved management of organic nitrogen and water
Mitigating methane emissions and global warming potential while increasing rice yield using biochar derived from leftover rice straw in a tropical paddy soil
Data availability
All data generated or analyzed during this study are included in this published article and its supplementary information files.
Abbreviations
- SP:
Shrimp ponds
- RM:
Rice monoculture
- RS:
Rice–shrimp coculture
References
IPCC. Summary for policymakers. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (Masson-Delmotte, V., Zhai, P., Pirani, A., Connors, S.L., Pean, C., Berger, S., Caud, N., Chen, Y., Goldfarb, L., Gomis, M.I., Huang, M., Leitzell, K., Lonnoy, E., Matthews, J.B.R., Maycock, T.K., Waterfield, T., Yelekçi, O., Yu, R., Zhou, B. Eds.). (Cambridge University Press, 2021). https://doi.org/10.1017/9781009157896
Zhou, Y. et al. Four decades of nitrous oxide emission from Chinese aquaculture underscores the urgency and opportunity for climate change mitigation. Environ. Res. Let. 16 (11), 114038. https://doi.org/10.1088/1748-9326/ac3177 (2021).
Fang, X. et al. Lower methane and nitrous oxide emissions from rice-aquaculture co-culture systems than from rice paddies in Southeast China. Agr For. Meteorol. 338, 109540. https://doi.org/10.1016/j.agrformet.2023.109540 (2023).
Yang, T. et al. Impact of rice-crab and rice-fish co-cultures on the methane emission and its transport in aquaculture ponds. Agr Ecosyst. Environ. 378, 109281. https://doi.org/10.1016/j.agee.2024.109281 (2025).
Datta, A., Nayak, D. R., Sinhababu, D. P. & Adhya, T. K. Methane and nitrous oxide emissions from an integrated rainfed rice–fish farming system of Eastern India. Agr Ecosyst. Environ. 129, 228–237. https://doi.org/10.1016/j.agee.2008.09.003 (2009).
Ma, Y. et al. A comparison of methane and nitrous oxide emissions from inland mixed-fish and crab aquaculture ponds. Sci. Total Environ. 637, 517–523. https://doi.org/10.1016/j.scitotenv.2018.05.040 (2018).
Hu, L. et al. Can the co-cultivation of rice and fish help sustain rice production? Sci. Rep. 6, 28728. https://doi.org/10.1038/srep28728 (2016).
Chen, D. et al. Effects of land-use conversion from Masson pine forests to tea plantations on net ecosystem carbon and greenhouse gas budgets. Agr Ecosyst. Environ. 320, 107578. https://doi.org/10.1016/j.agee.2021.107578 (2021).
Liu, S. et al. Methane and nitrous oxide emissions reduced following conversion of rice paddies to inland crab-fish aquaculture in Southeast China. Environ. Sci. Technol. 50 (2), 633–642. https://doi.org/10.1021/acs.est.5b04343 (2016).
Yang, P., Bastviken, D., Jin, B. S., Mou, X. J. & Tong, C. Effects of coastal marsh conversion to shrimp aquaculture ponds on CH4 and N2O emissions. Estuar. Coast Shelf S. 199, 125–131. https://doi.org/10.1016/j.ecss.2017.09.023 (2017a).
Tan, L. S. et al. Conversion of coastal wetlands, riparian wetlands, and peatlands increases greenhouse gas emissions: a global meta-analysis. Glob Change Biol. 26, 1638–1653. https://doi.org/10.1111/gcb.14933 (2020).
Lin, Q. W. et al. Effects and mechanisms of land-types conversion on greenhouse gas emissions in the yellow river floodplain wetland. Sci. Total Environ. 813, 152406. https://doi.org/10.1016/j.scitotenv.2021.152406 (2022).
Zou, J. et al. Changes in fertilizer-induced direct N2O emissions from paddy fields during rice-growing season in China between 1950s and 1990s. Glob Change Biol. 15 (1), 229–242. https://doi.org/10.1111/j.1365-2486.2008.01775.x (2009).
Zhang, W., Yu, Y. Q., Huang, Y., Li, T. & Wang, P. Modeling methane emissions from irrigated rice cultivation in China from 1960 to 2050. Glob Change Biol. 17, 3511–3523. https://doi.org/10.1111/j.1365-2486.2011.02495.x (2011).
Zhou, F. et al. New model for capturing the variations of fertilizer-induced emission factors of N2O. Glob. Biogeochem. Cyc. 29. https://doi.org/10.1002/2014GB005046 (2015).
Wu, S. et al. Annual methane and nitrous oxide emissions from rice paddies and inland fish aquaculture wetlands in Southeast China. Atmos. Environ. 175, 135–144. https://doi.org/10.1016/j.atmosenv.2017.12.008 (2018b).
Yu, K. et al. Low greenhouse gases emissions associated with high nitrogen use efficiency under optimized fertilization regimes in double-rice cropping systems. Appl. Soil. Ecol. 160, 103846. https://doi.org/10.1016/j.apsoil.2020.103846 (2021).
Gao, B., Ju, X. T., Zhang, Q., Christie, P. & Zhang, F. New estimates of direct N2O emissions from Chinese croplands from 1980 to 2007 using localized emission factors. Biogeosciences 8, 3011–3024. https://doi.org/10.5194/bgd-8-6971-2011 (2011).
Yang, P., Tang, K. W. & Tong, C. Conversion of coastal wetland to aquaculture ponds decreased N2O emission: evidence from a multi-year field study. Water Res. 227, 119326. https://doi.org/10.1016/j.watres.2022.119326 (2022).
Chen, Y., Dong, S., Wang, F., Gao, Q. & Tian, X. Carbon dioxide and methane fluxes from feeding and no-feeding mariculture ponds. Environ. Pollut. 212. https://doi.org/10.1016/j.envpol.2016.02.039 (2016).
Gao, D. et al. Effects of shrimp-aquaculture reclamation on sediment nitrate dissimilatory reduction processes in a coastal wetland of southeastern China. Environ. Pollut. 255, 113219. https://doi.org/10.1016/j.envpol.2019.113219 (2019).
Hu, Z. et al. Nitrogen transformations in intensive aquaculture system and its implication to climate change through nitrous oxide emission. Bioresour Technol. 130, 314–320. https://doi.org/10.1016/j.biortech.2012.12.033 (2013).
Paudel, S. R. et al. Effects of temperature on nitrous oxide (N2O) emission from intensive aquaculture system. Sci. Total. Environ. 518 – 519, 16 – 23. (2015). https://doi.org/10.1016/j.scitotenv.2015.02.076
Yang, P. et al. Large fine-scale Spatiotemporal variations of CH4 diffusive fluxes from shrimp aquaculture ponds affected by organic matter supply and aeration in Southeast China. J. Geophys. Res. Biogeo. 124, 1290–1307. https://doi.org/10.1029/2019JG005025 (2019a).
Tong, C. et al. Annual CO2 and CH4 fluxes in coastal earthen ponds with Litopenaeus vannamei in southeastern China. Aquaculture 545, 737229. https://doi.org/10.1016/j.aquaculture.2021.737229 (2021).
Kruse, J. et al. Land use change from permanent rice to alternating rice-shrimp or permanent shrimp in the coastal Mekong Delta, vietnam: changes in the nutrient status and binding forms. Sci. Total Environ. 703, 134758. https://doi.org/10.1016/j.scitotenv.2019.134758 (2020).
Jiang, Y. & Cao, C. Crayfish–rice integrated system of production: an agriculture success story in China. A review. Agron. Sustain. Dev. 41 (5). https://doi.org/10.1007/s13593-021-00724-w (2021).
Guo, L., Lin, W. & Cao, C. Integrated rice-crayfish farming system does not mitigate the global warming potential during rice season. Sci. Total Environ. 2023 (867), 161520. https://doi.org/10.1016/j.scitotenv.2023.161520 (2023).
Wang, A., Ma, X., Xu, J. & Lu, W. Methane and nitrous oxide emissions in rice-crab culture systems of Northeast China. Aquac Fish. 4 (4), 134–141. https://doi.org/10.1016/j.aaf.2018.12.006 (2019).
Liu, M., Yuan, J., Ni, M. & Lian, Q. Assessment of the effectiveness of a field-scale combined ecological treatment system at removing water pollutants, after optimization using a system dynamic model: A case study of rural inland ponds in China. Environ. Sci. Pollut. R. 29, 30169–30183 (2022). https://link.springer.com/article/10.1007%2Fs11356-021-17454-x
Gutlein, A., Gerschlauer, F., Kikoti, I. & Kiese, R. Impacts of climate and land use on N2O and CH4 fluxes from tropical ecosystems in the Mt. Kilimanjaro region. Tanzan. Glob Change Biol. 24, 1239–1255. https://doi.org/10.1111/gcb.13944 (2018).
Yang, P. et al. Large increase in CH4 emission following conversion of coastal marsh to aquaculture ponds caused by changing gas transport pathways. Water Res. 222, 11882. https://doi.org/10.1016/j.watres.2022.118882 (2022).
Sun, Z. et al. Effects of straw returning and feeding on greenhouse gas emissions from integrated rice-crayfish farming in Jianghan Plain. China Environ. Sci. Pollut R 26 (12), 11710–11718. https://doi.org/10.1007/s11356-019-04572-w. (2019).
Dien, L. D., Van Hao, N., Sammut, J. & Burford, M. A. Comparing nutrient budgets in integrated rice-shrimp ponds and shrimp grow-out ponds. Aquaculture 484, 250–258. https://doi.org/10.1016/j.aquaculture.2017.11.037 (2018).
Li, F. et al. Impact of rice-fish/shrimp co-culture on the N2O emission and NH3 volatilization in intensive aquaculture ponds. Sci. Total Environ. 655, 284–291. https://doi.org/10.1016/j.scitotenv.2018.10.440 (2019).
Han, L. et al. Co-occurrence of microplastics and hydrochar stimulated the methane emission but suppressed nitrous oxide emission from a rice paddy soil. J. Clean. Prod. 337, 130504. https://doi.org/10.1016/j.jclepro.2022.130504 (2022).
IPCC. Summary for policymakers. In Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley Eds.). (Cambridge University Press, 2013). https://www.ipcc.ch/site/assets/uploads/2018/03/WG1AR5_SummaryVolume_FINAL.pdf
Fang, X. et al. A two-year measurement of methane and nitrous oxide emissions from freshwater aquaculture ponds: affected by aquaculture species, stocking and water management. Sci. Total Environ. 813, 151863. https://doi.org/10.1016/j.scitotenv.2021.151863 (2021).
Yu, H. et al. A meta-analysis of ecological functions and economic benefits of co-culture models in paddy fields. Agr Ecosyst. Environ. 2023 (341), 108195. https://doi.org/10.1016/j.agee.2022.108195 (2023).
Liu, T. Q. et al. Rice-crayfish co-culture reduces ammonia volatilization and increases rice nitrogen uptake in central China. Agr Ecosyst. Environ. 330, 107869. https://doi.org/10.1016/j.agee.2022.107869 (2022).
Burford, M. A., Le, H. H., Sang, N. V., Khoi, C. M. & Sammut, J. Does natural feed supply the nutritional needs of shrimp in extensive rice-shrimp ponds? – A stable isotope tracer approach. Aquaculture 529, 735717. https://doi.org/10.1016/j.aquaculture.2020.735717 (2020).
Canion, A. et al. Temperature response of denitrifification and anaerobic ammonium oxidation rates and microbial community. Environ. Microbiol. 16, 3331–3344. https://doi.org/10.1111/1462-2920.12593 (2014).
Si, G., Peng, C., Yuan, J., Xu, X. & Zhao, S. Changes in soil microbial community composition and organic carbon fractions in an integrated rice-crayfish farming system in subtropical China. Sci. Rep. 7 (1), 2856. https://doi.org/10.1038/s41598-017-02984-7 (2017).
Hellman, M., Bonilla-Rosso, G., Widerlund, A., Juhanson, J. & Hallin, S. External carbon addition for enhancing denitrification modifies bacterial community composition and affects CH4 and N2O production in sub-arctic mining pond sediments. Water Res. 158, 22–33. https://doi.org/10.1016/j.watres.2019.04.007 (2019).
Fuchs, A., Lyautey, E., Montuelle, B. & Casper, P. Effects of increasing temperatures on methane concentrations and methanogenesis during experimental incubation of sediments from oligotrophic and mesotrophic lakes. J. Geophys. Res. Biogeo. 121, 1394–1406. https://doi.org/10.1002/2016JG003328 (2016).
Gruca-Rokosz, R., Szal, D., Bartoszek, L. & Pękala, A. Isotopic evidence for vertical diversification of methane production pathways in freshwater sediments of Nielisz reservoir (Poland). Catena 195, 104803. https://doi.org/10.1016/j.catena.2020.104803 (2020).
Musenze, R. S. et al. Assessing the Spatial and Temporal variability of diffusive methane and nitrous oxide emissions from subtropical freshwater reservoirs. Environ. Sci. Technol. 48, 14499–14507. https://doi.org/10.1021/es505324h (2014).
Inglett, K. S., Inglett, P. W., Reddy, K. R. & Osborne, T. Z. Temperature sensitivity of greenhouse gas production in wetland soils of different vegetation. Biogeochemistry 108, 77–90. https://doi.org/10.1007/s10533-011-9573-3 (2012).
Natchimuthu, S., Panneer Selvam, B. & Bastviken, D. Influence of weather variables on methane and carbon dioxide flux from a shallow pond. Biogeochemistry 119, 403–413. https://doi.org/10.1007/s10533-014-9976-z (2014).
Bhattacharyya, P. et al. Effect of fish species on methane and nitrous oxide emission in relation to soil C, N pools and enzymatic activities in minted shallow lowland rice-fish farming system. Agr Ecosyst. Environ. 176, 53–62. https://doi.org/10.1016/j.agee.2013.05.015 (2013).
Berberich, M. E., Beaulieu, J. J., Hamilton, T. L., Waldo, S. & Buffam, I. Spatial variability of sediment methane production and methanogen communities within a eutrophic reservoir: importance of organic matter source and quantity. Limnol. Oceanogr. 65, 1336–1358. https://doi.org/10.1002/lno.11392 (2020).
Frei, M. et al. Methane emissions and related physicochemical soil and water parameters in rice-fish systems in Bangladesh. Agr Ecosyst. Environ. 120 (2–4), 391–398. https://doi.org/10.1016/j.agee.2006.10.013 (2007).
Soued, C., del Giorgio, P. A. & Maranger, R. Nitrous oxide sinks and emissions in boreal aquatic networks in Quebec. Nat. Geosci. 9 (2), 116–120. https://doi.org/10.1038/ngeo2611 (2015).
Murrary, R. H., Erler, D. V. & Eyre, B. D. Nitrous oxide fluxes in estuarine environments: response to global change. Glob Change Biol. 21 (9), 3219–3245. https://doi.org/10.1111/gcb.12923 (2015).
Pärn, J. et al. Nitrogen-rich organic soils under warm well-drained conditions are global nitrous oxide emission hotspots. Nat. Commun. 9, 1135. https://doi.org/10.1038/s41467-018-03540-1 (2018).
Zhang, Z. et al. Rice-crayfish farming increases soil organic carbon. Agr Ecosyst. Environ. 329, 107857. https://doi.org/10.1016/j.agee.2022.107857 (2022).
Williams, J. & Crutzen, P. J. Nitrous oxide from aquaculture. Nat. Geosci. 3, 143. https://doi.org/10.1038/ngeo804 (2010).
Hu, Z., Lee, J. W., Chandran, K., Kim, S. & Khanal, S. K. Nitrous oxide (N2O) emission from aquaculture: A review. Environ. Sci. Techn. 46 (12), 6470–6480. https://doi.org/10.1021/es300110x (2012).
Fang, X. et al. Ebullitive CH4 flux and its mitigation potential by aeration in freshwater aquaculture: measurements and global data synthesis. Agr Ecosyst. Environ. 335, 108016. https://doi.org/10.1016/j.agee.2022.108016 (2022).
Acknowledgements
The project was supported by the Huzhou Public-Welfare Applied Research Project (No. 2022GZ24), Zhejiang Key Research and Development Project of China (No. 2022C02027) .
Author information
Authors and Affiliations
Contributions
Mei Liu: methodology, data curation, writing-original draft. Minpeng Hu: conceptualization, methodology. Dan Zhou and Songbao Zou: data curation, investigation. Yu Zhang and Bin He: investigation, visualization. Meng Ni: prepared figures and tables. Julin Yuan: supervision, writing-original draft. All authors reviewed the manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary Information
Below is the link to the electronic supplementary material.
Supplementary Material 1
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
Reprints and permissions
About this article
Cite this article
Liu, M., Hu, M., Zhou, D. et al. CH4 and N2O emissions increased following the conversion of aquaculture ponds to rice monoculture and rice–shrimp coculture fields in southeast China.
Sci Rep (2025). https://doi.org/10.1038/s41598-025-28979-3
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41598-025-28979-3
Keywords
- Reclaimed land
- Rice–shrimp coculture
- CH4 and N2O emissions
- Environmental factors
Source: Ecology - nature.com
