Variation characteristics of CO<sub>2</sub> in a newly-excavated soil profile, Chinese Loess Plateau: Excavation-induced ancient soil organic carbon decomposition

Chao Song; Man Liu; Qiu-yao Dong; Lin Zhang; Pan Wang; Hong-yun Chen; Rong Ma

doi:10.19637/j.cnki.2305-7068.2022.01.003

Volume 10 Issue 1

Mar. 2022

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Song C, Liu M, Dong QY, et al. 2022. Variation characteristics of CO2 in a newly-excavated soil profile, Chinese Loess Plateau: Excavation-induced ancient soil organic carbon decomposition. Journal of Groundwater Science and Engineering, 10(1): 19-32 doi: 10.19637/j.cnki.2305-7068.2022.01.003

Citation:

Song C, Liu M, Dong QY, et al. 2022. Variation characteristics of CO₂ in a newly-excavated soil profile, Chinese Loess Plateau: Excavation-induced ancient soil organic carbon decomposition. Journal of Groundwater Science and Engineering, 10(1): 19-32 doi: 10.19637/j.cnki.2305-7068.2022.01.003

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Variation characteristics of CO₂ in a newly-excavated soil profile, Chinese Loess Plateau: Excavation-induced ancient soil organic carbon decomposition

doi: 10.19637/j.cnki.2305-7068.2022.01.003

Chao Song^{1, 2},
Man Liu³,
Qiu-yao Dong^{1, 2
,
,},
Lin Zhang^{1, 2},
Pan Wang^{1, 2},
Hong-yun Chen^{1, 2},
Rong Ma⁴

1.
Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang 050061, China
2.
Key Laboratory of Quaternary Chronology and Hydro-Environmental Evolution, China Geological Survey, Shijiazhuang 050061, China
3.
Institute of Earth Sciences, China University of Geosciences (Beijing), Beijing 100083, China
4.
State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China

More Information

Corresponding author: dongqiuyao@mail.cgs.gov.cn
Received Date: 2021-03-20
Accepted Date: 2021-12-25

Available Online: 2022-03-24

Publish Date: 2022-03-15

Abstract

Abstract

Soils of the Chinese Loess Plateau (CLP) contain substantial amounts of soil inorganic carbon (SIC), as well as recent and ancient soil organic carbon (SOC). With the advent of the Anthropocene, human perturbation, including excavation, has increased soil CO₂ emission from the huge loess carbon pool. This study aims to determine the potential of loess CO₂ emission induced by excavation. Soil CO₂ were continuously monitored for seven years on a newly-excavated profile in the central CLP and the stable C isotope compositions of soil CO₂ and SOC were used to identify their sources. The results showed that the soil CO₂ concentrations ranged from 830 μL·L⁻¹ to 11 190 μL·L⁻¹ with an annually reducing trend after excavation, indicating that the human excavation can induce CO₂ production in loess profile. The δ¹³C of CO₂ ranged from –21.27 ‰ to –19.22 ‰ (mean: –20.11‰), with positive deviation from top to bottom. The range of δ¹³C_SOC was –24.0‰ to –21.1‰ with an average of –23.1‰. The δ¹³C-CO₂ in this study has a positive relationship with the reversed CO₂ concentration, and it is calculated that 80.22% of the soil CO₂ in this profile is from the microbial decomposition of SOC and 19.78% from the degasification during carbonate precipitation. We conclude that the human excavation can significantly enhance the decomposition of the ancient OC in loess during the first two years after perturbation, producing and releasing soil CO₂ to atmosphere.
- Soil organic matter,
- Human excavation,
- Soil CO₂,
- Stable carbon isotopic composition,
- China Loess Plateau

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References(66)

References

Andrews JA, Schlesinger WH. 2001. Soil CO₂ dynamics, acidification, and chemical weathering in a temperate forest with experimental CO₂ enrichment. Global Biogeochemical Cycles, 15(1): 149-162. doi: 10.1029/2000gb001278

Arora B, Spycher NF, Steefel CI, et al. 2016. Influence of hydrological, biogeochemical and temperature transients on subsurface carbon fluxes in a flood plain environment. Biogeochemistry, 127(2-3): 367-396. doi: 10.1007/s10533-016-0186-8

Capaccioni B, Caramiello C, Tatàno F, et al. 2011. Effects of a temporary HDPE cover on landfill gas emissions: Multiyear evaluation with the static chamber approach at an Italian landfill. Waste Management, 31(5): 956-965. doi: 10.1016/j.wasman.2010.10.004

Chaopricha NT, Marín-Spiotta E. 2014. Soil burial contributes to deep soil organic carbon storage. Soil Biology and Biochemistry, 69: 251-264. doi: 10.1016/j.soilbio.2013.11.011

Chen D, Wei W, Daryanto S, Tarolli P. 2020. Does terracing enhance soil organic carbon sequestration? A national-scale data analysis in China. Science of the Total Environment, 721: 137751. doi: 10.1016/j.scitotenv.2020.137751

Chen Q, Shen C, Sun Y, et al. 2007. Characteristics of soil organic carbon and its isotopic compositions. Chinese Journal of Ecology, 26(9): 1327-1334. doi: 10.13292/j.1000-4890.2007.0255

Cleveland CC, Nemergut DR, Schmidt SK, et al. 2007. Increases in soil respiration following labile carbon additions linked to rapid shifts in soil microbial community composition. Biogeochemistry, 82(3): 229-240. doi: 10.1007/s10533-006-9065-z

Deng Q, Hui D, Chu G, et al. 2017. Rain-induced changes in soil CO₂ flux and microbial community composition in a tropical forest of China. Scientific Reports, 7(1): 5539. doi: 10.1038/s41598-017-06345-2

Etiope G. 1999. Subsoil CO₂ and CH₄ and their advective transfer from faulted grassland to the atmosphere. Journal of Geophysical Research:Atmospheres, 104(D14): 16889-16894. doi: 10.1029/1999JD900299

Fierer N, Schimel JP. 2003. A proposed mechanism for the pulse in carbon dioxide production commonly observed following the rapid rewetting of a dry soil. Soil Science Society of America Journal, 67(3): 798-805. doi: 10.2136/sssaj2003.0798

Flechard CR, Neftel A, Jocher M, et al. 2007. Temporal changes in soil pore space CO₂ concentration and storage under permanent grassland. Agricultural and Forest Meteorology, 142(1): 66-84. doi: 10.1016/j.agrformet.2006.11.006

Fontaine S, Barot S, Barré P, et al. 2007. Stability of organic carbon in deep soil layers controlled by fresh carbon supply. Nature, 450(7167): 277-280. doi: 10.1038/nature06275

Gao Y, Tian J, Pang Y, et al. 2017. Soil inorganic carbon sequestration following afforestation is probably induced by pedogenic carbonate formation in Northwest China. Frontiers in Plant Science, 8: 1282. doi: 10.3389/fpls.2017.01282

Gerke H, Rieckh H, Sommer M. 2015. Interactions between crop, water, and dissolved organic and inorganic carbon in a hummocky landscape with erosion-affected pedogenesis. Soil and Tillage Research, 156: 230-244. doi: 10.1016/j.still.2015.09.003

Granieri D, Chiodini G, Marzocchi W, et al. 2003. Continuous monitoring of CO₂ soil diffuse degassing at Phlegraean Fields (Italy): Influence of environmental and volcanic parameters. Earth and Planetary Science Letters, 212(1-2): 167-179. doi: 10.1016/S0012-821X(03)00232-2

Han G, Yang T, Man L, et al. 2020. Carbon-nitrogen isotope coupling of soil organic matter in a karst region under land use change, Southwest China. Agriculture Ecosystems & Environment, 301: 107027. doi: 10.1016/j.agee.2020.107027

Hashimoto S, Komatsu H. 2006. Relationships between soil CO₂ concentration and CO₂ production, temperature, water content, and gas diffusivity: implications for field studies through sensitivity analyses. Journal of Forest Research, 11(1): 41-50. doi: 10.1007/s10310-005-0185-4

Hashimoto S, Tanaka N, Kume T, et al. 2007. Seasonality of vertically partitioned soil CO₂ production in temperate and tropical forest. Journal of Forest Research, 12(3): 209-221. doi: 10.1007/s10310-007-0009-9

Hendry MJ, Mendoza CA, Kirkland RA, et al. 1999. Quantification of transient CO₂ production in a sandy unsaturated zone. Water Resour. Res, 35(7): 2189-2198. doi: 10.1029/1999WR900060

IPCC. 2018. Global Warming of 1.5℃: An IPCC Special Report on the impacts of global warming of 1.5℃ above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty.

IPCC. 2021. Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. In: Masson-Delmotte V, Zhai P, Pirani A, et al.

Jassal R, Black A, Novak M, et al. 2005. Relationship between soil CO₂ concentrations and forest-floor CO₂ effluxes. Agricultural and Forest Meteorology, 130: 176-192. doi: 10.1016/j.agrformet.2005.03.005

Jassal RS, Black TA, Drewitt GB, et al. 2004. A model of the production and transport of CO₂ in soil: Predicting soil CO₂ concentrations and CO₂ efflux from a forest floor. Agricultural and Forest Meteorology, 124(3-4): 219-236. doi: 10.1016/j.agrformet.2004.01.013

Jobbágy E, Jackson R. 2000. The vertical distribution of soil organic carbon and its relation to climate and vegetation. Ecological Applications, 10(2): 423-436. doi: 10.1890/1051-0761(2000)010[0423:TVDOSO]2.0.CO;2

Johnson MS, Lehmann J, Riha SJ, et al. 2008. CO₂ efflux from Amazonian headwater streams represents a significant fate for deep soil respiration. Geophysical Research Letters, 35(L17401): 1-5. doi: 10.1029/2008GL034619

Keller CK, Bacon DH. 1998. Soil respiration and georespiration distinguished by transport analyses of vadose CO₂, ¹³CO₂, and ¹⁴CO₂. Global Biogeochemical Cycles, 12(2): 361-372. doi: 10.1029/98GB00742

Koehler B, Zehe E, Corre MD, et al. 2010. An inverse analysis reveals limitations of the soil-CO₂ profile method to calculate CO₂ production and efflux for well-structured soils. Biogeosciences, 7: 2311-2325. doi: 10.5194/bg-7-2311-2010

Lal R. 2004. Soil carbon sequestration impacts on global climate change and food security. Science, 304: 1623-1627. doi: 10.1126/science.1097396

Lee RW. 1997. Effects of carbon dioxide variations in the unsaturated zone on water chemistry in a glacial-outwash aquifer. Applied Geochemistry, 12(4): 347-366. doi: 10.1016/S0883-2927(97)00001-2

Lee X, Wu H, Sigler J, et al. 2004. Rapid and transient response of soil respiration to rain. Global Change Biology, 10: 1017-1026. doi: 10.1111/j.1365-2486.2004.00787.x

Liegler A. 2016. Diffuse CO₂ degassing and the origin of volcanic gas variability from Rincón de la Vieja, Miravalles and Tenorio Volcanoes, Guanacaste Province, Costa Rica. M. S. thesis. Houghton, Michigan: Michigan Technological University: 1-69.

Liu J, Han G. 2020. Effects of chemical weathering and CO₂ outgassing on δ¹³C DIC signals in a karst watershed. Journal of Hydrology, 589: 125192. doi: 10.1016/j.jhydrol.2020.125192

Liu J, Hua Z, Liu D. 1997. Preliminary study of greenhouse gases in loess in Weinan, Shaanxi Province. Chinese Science Bulletin, 42(11): 921-924. doi: 10.1007/BF02882548

Liu M, Han G, Li X. 2021. Comparative analysis of soil nutrients under different land-use types in the Mun River basin of Northeast Thailand. Journal of Soils and Sediments(21): 1136-1150. doi: 10.1007/s11368-020-02870-2

Liu M, Han G, Zhang Q. 2020. Effects of agricultural abandonment on soil aggregation, soil organic carbon storage and stabilization: Results from observation in a small karst catchment, Southwest China. Agriculture, Ecosystems & Environment, 288: 106719.

Liu Q, Liu J, Sui S. 2001. Features of major greenhouse gases in loess, Shanxi Province, China. Chinese Science Bulletin, 46(17): 1469-1471. doi: 10.1007/BF03187034

Liu T. 1985. Loess and the Environment. Beijing: China Ocean Press. 1-481. (In Chinese)

Liu W, Yang H, Ning Y, et al. 2007. Contribution of inherent organic carbon to the bulk δ¹³C signal in loess deposits from the arid western Chinese Loess Plateau. Organic Geochemistry, 38(9): 1571-1579. doi: 10.1016/j.orggeochem.2007.05.004

Liu W, Yang H, Sun Y, et al. 2011. δ¹³C Values of loess total carbonate: A sensitive proxy for Asian summer monsoon in arid northwestern margin of the Chinese loess plateau. Chemical Geology, 3-4(284): 317-322. doi: 10.1016/j.chemgeo.2011.03.011

Liu X, Wan S, Su B, et al. 2002. Response of soil CO₂ efflux to water manipulation in a tallgrass prairie ecosystem. Plant and Soil, 240(2): 213-223. doi: 10.1023/A:1015744126533

Liu Z. 2011. Is pedogenic carbonate an important atmospheric CO₂ sink? Chinese Science Bulletin, 56(35): 3794-3796.

Lu H, Hongyan Z, Lin Z, et al. 2015. Temperature forced vegetation varations in glacial interglacial cycles in northeastern China revealed by loess palesol deposit. Quaternary Sciences, 35(4): 828-836. doi: 10.11928/j.issn.1001-7410.2015.04.05

Lyu A, Lu H, Lin Z, et al. 2018. Variation and possible forcing mechanism of organic carbon isotopic compositions of loess in Northeastern China over the past 1. 08 Ma. Journal of Asian Earth Sciences, 155: 174-179. doi: 10.1016/j.jseaes.2017.11.013

Maier M, Schack-Kirchner H, Hildebrand EE, et al. 2010. Pore-space CO₂ dynamics in a deep, well-aerated soil. European Journal of Soil Science, 61(6): 877-887. doi: 10.1111/j.1365-2389.2010.01287.x

Maier M, Schack-Kirchner H, Hildebrand EE, et al. 2011. Soil CO₂ efflux vs. soil respiration: Implications for flux models. Agricultural & Forest Meteorology, 151(12): 1723-1730. doi: 10.1016/j.agrformet.2011.07.006

Pabst H, Gerschlauer F, Kiese R, et al. 2016. Land use and precipitation affect organic and microbial carbon stocks and the specific metabolic quotient in soils of eleven ecosystems of Mt. Kilimanjaro, Tanzania. Land Degradation & Development, 27(3): 592-602.

Pengthamkeerati P, Motavalli PP, Kremer RJ, et al. 2005. Soil carbon dioxide efflux from a claypan soil affected by surface compaction and applications of poultry litter. Agriculture, Ecosystems and Environment, 109(1): 75-86.

Popiţa G, Frunzeti N, Ionescu A, et al. 2015. Evaluation of carbon dioxide and methane emission from Cluj-Napoca municipal landfill, Romania. Environmental Engineering and Management Journal, 14(6): 1389-1398. doi: 10.30638/eemj.2015.151

Qin XG, Li CS, Cai BG. 2001. The sensitivity simulation of climate impact on C pools of loess. Quaternary Sciences, 21(2): 153-161.

Reardon EJ, Allison GB, Fritz P. 1979. Seasonal chemical and isotopic variations of soil CO₂ at Trout Creek, Ontario. Journal of Hydrology, 43(1): 355-371. doi: 10.1016/0022-1694(79)90181-1

Song C, Han G, Ning Z, et al. 2017a. The characteristics and origin of CO₂ in unsaturated zone at loess tableland of Northwestern China. Quaternary Research, 37(6): 1172-1181. doi: 10.11928/j.issn.1001-7410.2017.06.02

Song C, Han G, Shi Y, et al. 2017b. Characteristics of CO₂ in unsaturated zone(~90 m) of loess tableland, Northwest China. Acta Geochimica, 36(3): 489-493. doi: 10.1007/s11631-017-0214-y

Song C. 2017. Characteristics and origin of soil CO₂ at unsaturated zone in loess tableland and its implication to carbon cycle. Ph. D. thesis. Beijing: China University of Geosciences (Beijing): 1-132. (In Chinese)

Suchomel KH, Kreamer DK, Long A. 1990. Production and transport of carbon dioxide in a contaminated vadose zone: a stable and radioactive carbon isotope study. Environmental science & technology, 24(12): 1824-1831. doi: 10.1021/es00082a006

Tan W, Zhang R, Cao H, et al. 2014. Soil inorganic carbon stock under different soil types and land uses on the Loess Plateau region of China. Catena, 121: 22-30. doi: 10.1016/j.catena.2014.04.014

Thorstenson DC, Weeks EP, Haas H, et al. 1998. Chemistry of unsaturated zone gases sampled in open boreholes at the crest of Yucca Mountain, Nevada: Data and basic concepts of chemical and physical processes in the mountain. Water resources research, 34(6): 1507-1529. doi: 10.1029/98WR00267

Walvoord MA, Striegl RG, Prudic DE, et al. 2005. CO₂ dynamics in the Amargosa Desert: Fluxes and isotopic speciation in a deep unsaturated zone. Water resources research, 41(2): W02006. doi: 10.1029/2004WR003599

Wang C, Li F, Shi H, et al. 2013. The significant role of inorganic matters in preservation and stability of soil organic carbon in the Baoji and Luochuan loess/paleosol profiles, Central China. Catena, 109: 186-194. doi: 10.1016/j.catena.2013.04.001

Wang JP, Wang XJ, Zhang J, et al. 2015. Soil organic and inorganic carbon and stable carbon isotopes in the Yanqi Basin of northwestern China. European Journal of Soil Science, 66(1): 95-103. doi: 10.1111/ejss.12188

Wood WW, Petraitis MJ. 1984. Origin and distribution of carbon dioxide in the unsaturated zone of the southern high plains of Texas. Water Resources Research, 20(9): 1193-1208. doi: 10.1029/WR020i009p01193

Xiang SR, Doyle A, Holden PA, et al. 2008. Drying and rewetting effects on C and N mineralization and microbial activity in surface and subsurface California grassland soils. Soil Biology and Biochemistry, 40(9): 2281-2289. doi: 10.1016/j.soilbio.2008.05.004

Yang S, Ding Z, Li Y, et al. 2015. Warming-induced northwestward migration of the East Asian monsoon rain belt from the Last Glacial Maximum to the mid-Holocene. Proceedings of the National Academy of Sciences of the United States of America, 112(43): 13183. doi: 10.1073/pnas.1504688112

Zamanian K, Pustovoytov K, Kuzyakov Y. 2016. Pedogenic carbonates: Forms and formation processes. Earth Science Reviews, 157: 1-17. doi: 10.1016/j.earscirev.2016.03.003

Zamanian K, Zarebanadkouki M, Kuzyakov Y. 2018. Nitrogen fertilization raises CO₂ efflux from inorganic carbon: A global assessment. Global Change Biology, (24): 2810-2817. doi: 10.1111/gcb.14148

Zhou B, Shen C, Sun W, et al. 2014. Late Pliocene-Pleistocene expansion of C₄ vegetation in semiarid East Asia linked to increased burning. Geology, 42(12): 1067-1070. doi: 10.1130/G36110.1

Zhou B, Wali G, Peterse F, et al. 2016. Organic carbon isotope and molecular fossil records of vegetation evolution in central Loess Plateau since 450 kyr. Science China, 59(6): 1206-1215. doi: 10.1007/s11430-016-5276-x

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