Grazing regimes modulate organic carbon distribution in soil aggregates over varying soil depths in steppe grasslands

Abstract

Soil organic carbon (SOC) reflects soil quality and affects ecosystem productivity and the capacity for carbon sequestration. Grazing regimes modulate the status of SOC in grasslands, but their impacts on SOC distribution among soil aggregates are not entirely clear. In this study, the effects of grazing with different intensities and no-grazing with varied enclosure durations were investigated. Increasing grazing intensity enhanced the proportion of 150‒53 μm aggregates, while reducing larger aggregates. After 5 years of enclosure, the distribution of soil aggregates in heavily degraded grassland recovered to resemble that in light-grazed grassland. Heavy grazing decreased SOC concentration in the 10–20 cm layer, and SOC concentration in different aggregate sizes decreased with increasing grazing intensity. Differences in SOC stocks among management measures were mainly reflected in the 10–20 cm soil layer, with heavy grazing significantly reducing SOC stocks. SOC stocks were lowest in 2000–250 μm and 250–150 μm aggregates and highest in <20 μm aggregates. Moderate grazing enhanced SOC stocks in <20 μm aggregates. In the 10–20 cm soil layer, 10 years of enclosure significantly decreased SOC stocks in 2000–250 μm, 250–150 μm and <20 μm aggregates compared to 5 years of enclosure. It indicated that grazing regimes affected grassland carbon sequestration and its distribution in soil aggregates, and moderate grazing had a better positive effect on carbon sequestration. This study provides novel insights into the patterns underlying changes in soil organic carbon from soil aggregates perspective.

Graphical abstract

Keywords

soil organic carbon / organic carbon distribution / grazing regimes / soil depth / soil aggregates

Highlight

	● Grazing regimes affect the distribution of soil aggregates.
	● Grazing regimes affect the distribution of soil organic carbon (SOC).
	● Differences in SOC concentration and stock were mainly found in the 10‒20 cm soil.
	● Moderate grazing is favorable to increase grassland SOC storage.

References

[1] Arunrat, N., Kongsurakan, P., Sereenonchai, S., Hatano, R., 2020. Soil organic carbon in sandy paddy fields of northeast Thailand: a review. Agronomy10, 1061.

[2] Bai, X.J., Yang, X.A., Zhang, S.M., An, S.S., 2021. Newly assimilated carbon allocation in grassland communities under different grazing enclosure times. Biology and Fertility of Soils57, 563–574.

[3] Bai, Y.F., Shang, J.Y., Tang, S.M., Wang, L.P., Zhang, Y.J., Wang K., Liu, K.S., 2016. The effect of different uses of grassland on spatial distribution of soil particle size in Hebei Ectone. Acta Agrestia Sinica24, 530–536.

[4] Bastida, F., Eldridge, D.J., García, C., Kenny Png, G., Bardgett, R.D., Delgado-Baquerizo, M., 2021. Soil microbial diversity–biomass relationships are driven by soil carbon content across global biomes. The ISME Journal15, 2081–2091.

[5] Dai, Y.J., Guo, J.Y., Li, Y.Q., Dong, Z., Li, H.L. 2022. , Soil physical and chemical properties affected by long-term grazing on the desert steppe of Inner Mongolia, China. CATENA211, 105996.

[6] Dastgheyb Shirazi, S.S., Ahmadi, A., Abdi, N., Toranj Zar, H., Khaleghi, M.R., 2021. Moderate grazing is the best measure to achieve the optimal conservation and soil resource utilization (case study: Bozdaghin rangelands, North Khorasan, Iran). Environmental Monitoring and Assessment193, 549.

[7] Dong, L., Wang, J., Li, J.R., Wu, Y.T., Zheng, Y., Zhang, J.H., Li, Z.Y., Yin, R.P., Liang, C.Z., 2022. Assessing the impact of grazing management on wind erosion risk in grasslands: a case study on how grazing affects aboveground biomass and soil particle composition in Inner Mongolia. Global Ecology and Conservation40, e02344.

[8] Evans, C.R.W., Krzic, M., Broersma, K., Thompson, D.J., 2012. Long-term grazing effects on grassland soil properties in southern British Columbia. Canadian Journal of Soil Science92, 685–693.

[9] Fan, J.L., Jin, H., Zhang, C.H., Zheng, J.J., Zhang, J., Han, G.D., 2021. Grazing intensity induced alternations of soil microbial community composition in aggregates drive soil organic carbon turnover in a desert steppe. Agriculture, Ecosystems & Environment313, 107387.

[10] Fan, L.L., Liang, Y.Y., Li, X.F., Mao, J.F., Wang, G.Y., Ma, X.X., Li, Y.M., 2023. Grazing decreases soil aggregation and has different effects on soil organic carbon storage across different grassland types in northern Xinjiang, China. Land12, 1575.

[11] Grilli, E., Carvalho, S.C.P., Chiti, T., Coppola, E., D’Ascoli, R., La Mantia, T., Marzaioli, R., Mastrocicco, M., Pulido, F., Rutigliano, F.A., Quatrini, P., Castaldi, S., 2021. Critical range of soil organic carbon in southern Europe lands under desertification risk. Journal of Environmental Management287, 112285.

[12] Gude, A., Kandeler, E., Gleixner, G., 2012. Input related microbial carbon dynamic of soil organic matter in particle size fractions. Soil Biology and Biochemistry47, 209–219.

[13] Hassink, J., Whitmore, A.P., Kubát, J., 1997. Size and density fractionation of soil organic matter and the physical capacity of soils to protect organic matter. European Journal of Agronomy7, 189–199.

[14] He, N.P., Wu, L., Wang, Y.S., Han, X.G., 2009. Changes in carbon and nitrogen in soil particle-size fractions along a grassland restoration chronosequence in northern China. Geoderma150, 302–308.

[15] He, Y.H., Zhao, H.L., Liu, X.P., Zhao, X.Y., Li, Y.Q., 2008. Soil physical and chemical characteristics of sandy meadow in natural restoration process. Journal of Soil and Water Conservation22, 159–161,181.

[16] Hewins, D.B., Fatemi, F., Adams, B., Carlyle, C.N., Chang, S.X., Bork, E.W., 2015. Grazing, regional climate and soil biophysical impacts on microbial enzyme activity in grassland soil of western Canada. Pedobiologia58, 201–209.

[17] Hu, Z.M., Li, S.G., Guo, Q., Niu, S.L., He, N.P., Li, L.H., Yu, G.R., 2016. A synthesis of the effect of grazing exclusion on carbon dynamics in grasslands in China. Global Change Biology22, 1385–1393.

[18] Jiang, Z.Y., Hu, Z.M., Lai, D.Y.F., Han, D.R., Wang, M., Liu, M., Zhang, M., Guo, M.Y., 2020. Light grazing facilitates carbon accumulation in subsoil in Chinese grasslands: a meta-analysis. Global Change Biology26, 7186–7197.

[19] Kabir, E.B., Bashari, H., Mosaddeghi, M.R., Bassiri, M., 2017. Soil aggregate stability and organic matter as affected by land-use change in central Iran. Archives of Agronomy and Soil Science63, 1823–1837.

[20] Khosravi, H., Ebrahimi, M., Rigi, M., 2017. Effects of rangeland exclusion on plant cover and soil properties in a steppe rangeland of southeastern Iran. Arid Land Research and Management31, 352–371.

[21] Klumpp, K., Fontaine, S., Attard, E., Le Roux, X., Gleixner, G., Soussana, J.F., 2009. Grazing triggers soil carbon loss by altering plant roots and their control on soil microbial community. Journal of Ecology97, 876–885.

[22] Lal, R., 2004. Soil carbon sequestration to mitigate climate change. Geoderma123, 1–22.

[23] Li, G.Y., Cai, J.T., Song, X.X., Pan, X.B., Pan, D.F., Jiang, S.C., Sun, J.Y., Zhang, M.N., Wang, L., 2022. Herbivore grazing mitigates the negative effects of nitrogen deposition on soil organic carbon in low-diversity grassland. Journal of Applied Ecology59, 483–491.

[24] Li, Y.Q., Zhao, J.B., 2005. Effects of overgrazing on ecological and environmental construction and measurement. Journal of Desert Research25, 404–408.

[25] Li, Y.Y., Dong, S.K., Wen, L., Wang, X.X., Wu, Y., 2014. Soil carbon and nitrogen pools and their relationship to plant and soil dynamics of degraded and artificially restored grasslands of the Qinghai–Tibetan Plateau. Geoderma213, 178–184.

[26] Liang, M.W., Smith, N.G., Chen, J.Q., Wu, Y.T., Guo, Z.W., Gornish, E.S., Liang, C.Z., 2021. Shifts in plant composition mediate grazing effects on carbon cycling in grasslands. Journal of Applied Ecology58, 518–527.

[27] Liu, D.D., Ju, W.L., Jin, X.L., Li, M.D., Shen, G.T., Duan, C.J., Guo, L., Liu, Y.Y., Zhao, W., Fang, L.C., 2021a. Associated soil aggregate nutrients and controlling factors on aggregate stability in semiarid grassland under different grazing prohibition timeframes. Science of the Total Environment777, 146104.

[28] Liu, K., Sollenberger, L.E., Newman, Y.C., Vendramini, J.M.B., Interrante, S.M., White‐Leech, R., 2011. Grazing management effects on productivity, nutritive value, and persistence of ‘Tifton 85’ bermudagrass. Crop Science51, 353–360.

[29] Liu, M., Ouyang, S.N., Tian, Y.Q., Wen, S.H., Zhao, Y., Li, X.B., Baoyin, T.T., Kuzyakov, Y., Xu, X.L., 2021b. Effects of rotational and continuous overgrazing on newly assimilated C allocation. Biology and Fertility of Soils57, 193–202.

[30] Liu, S.B., Schleuss, P.M., Kuzyakov, Y., 2017. Carbon and nitrogen losses from soil depend on degradation of Tibetan Kobresia Pastures. Land Degradation & Development28, 1253–1262.

[31] Liu, W.T., Sun, S.X., Wei, Z.J., 2020. Linking phytogenic hillocks with plant ecological strategies in a desert steppe: adaptation of Stipa breviflora to heavy grazing. Ecological Indicators117, 106564.

[32] Lorenz, K., Lal, R., Ehlers, K., 2019. Soil organic carbon stock as an indicator for monitoring land and soil degradation in relation to United Nations’ Sustainable Development Goals. Land Degradation & Development30, 824–838.

[33] Ma, Y.Q., Yu, Y., Nan, S.Z., Chai, Y., Xu, W.Y., Qin, Y., Li, X.L., Bodner, G., 2024. Conversion of SIC to SOC enhances soil carbon sequestration and soil structural stability in alpine ecosystems of the Qinghai-Tibet Plateau. Soil Biology and Biochemistry195, 109452.

[34] Martinsen, V., Mulder, J., Austrheim, G., Mysterud, A., 2011. Carbon storage in low-alpine grassland soils: effects of different grazing intensities of sheep. European Journal of Soil Science62, 822–833.

[35] McSherry, M.E., Ritchie, M.E., 2013. Effects of grazing on grassland soil carbon: a global review. Global Change Biology19, 1347–1357.

[36] Murphy, B.W., 2015. Impact of soil organic matter on soil properties-a review with emphasis on Australian soils. Soil Research53, 605–635.

[37] Nahidan, S., Nourbakhsh, F., 2018. Distribution pattern of amidohydrolase activities among soil aggregates: effect of soil aggregates isolation methods. Applied Soil Ecology125, 250–256.

[38] Pan, H., Liu, H.Y., Liu, Y.W., Zhang, Q.C., Luo, Y., Liu, X.M., Liu, Y.M., Xu, J.M., Di, H.J., Li, Y., 2018. Understanding the relationships between grazing intensity and the distribution of nitrifying communities in grassland soils. Science of the Total Environment634, 1157–1164.

[39] Peng, C.J., Shi, L.N., He, Y.C., Yao, Z.Y., Lin, Z.R., Hu, M.A., Yin, N., Xu, H.K., Li, Y.K., Zhou, H.K., Lu, X.M., Liu, K.S., Shao, X.Q., 2023. Climate factors regulate the depth dependency of soil organic carbon under grazing exclusion in Chinese grasslands: a meta-analysis. Land Degradation & Development34, 4924–4934.

[40] Ren, G.H., Wang, C.X., Dong, K.H., Zhu, H.S., Wang, Y.C., Zhao, X., 2018. Effects of grazing exclusion on soil-vegetation relationships in a semiarid grassland on the Loess Plateau, China. Land Degradation & Development29, 4071–4079.

[41] Rutledge, S., Wall, A.M., Mudge, P.L., Troughton, B., Campbell, D.I., Pronger, J., Joshi, C., Schipper, L.A., 2017. The carbon balance of temperate grasslands Part I: the impact of increased species diversity. Agriculture, Ecosystems & Environment239, 310–323.

[42] Shiau, Y.J., Chen, J.S., Chung, T.L., Tian, G.L., Chiu, C.Y., 2017. ¹³C NMR spectroscopy characterization of particle-size fractionated soil organic carbon in subalpine forest and grassland ecosystems. Botanical Studies58, 23.

[43] Shrestha, G., Stahl, P.D., 2008. Carbon accumulation and storage in semi-arid sagebrush steppe: effects of long-term grazing exclusion. Agriculture, Ecosystems & Environment125, 173–181.

[44] Socher, S.A., Prati, D., Boch, S., Müller, J., Klaus, V.H., Hölzel, N., Fischer, M., 2012. Direct and productivity-mediated indirect effects of fertilization, mowing and grazing on grassland species richness. Journal of Ecology100, 1391–1399.

[45] Trivedi, P., Rochester, I.J., Trivedi, C., Van Nostrand, J.D., Zhou, J.Z., Karunaratne, S., Anderson, I.C., Singh, B.K., 2015. Soil aggregate size mediates the impacts of cropping regimes on soil carbon and microbial communities. Soil Biology and Biochemistry91, 169–181.

[46] van N. du Toit, G., Snyman, H.A., Malan, P.J., 2009. Physical impact of grazing by sheep on soil parameters in the Nama Karoo subshrub/grass rangeland of South Africa. Journal of Arid Environments73, 804–810.

[47] Verchot, L.V., Dutaur, L., Shepherd, K.D., Albrecht, A., 2011. Organic matter stabilization in soil aggregates: understanding the biogeochemical mechanisms that determine the fate of carbon inputs in soils. Geoderma161, 182–193.

[48] Viglizzo, E.F., Ricard, M.F., Taboada, M.A., Vázquez-Amábile, G., 2019. Reassessing the role of grazing lands in carbon-balance estimations: meta-analysis and review. Science of the Total Environment661, 531–542.

[49] Wang, J.W., Zhao, C.Z., Zhao, L.C., Wen, J., Li, Q., 2020. Effects of grazing on the allocation of mass of soil aggregates and aggregate-associated organic carbon in an alpine meadow. PLoS One15, e0234477.

[50] Wang, S.Z., Fan, J.W., Liu S., 2017. A comprehensive analysis of difference in carbon stock estimation in the grasslands of China. Acta Agrestia Sinica25, 905–913.

[51] Wang, Z.P., Han, X.G., Chang, S.X., Wang, B., Yu, Q., Hou, L.Y., Li, L.H., 2013. Soil organic and inorganic carbon contents under various land uses across a transect of continental steppes in Inner Mongolia. CATENA109, 110–117.

[52] Wiesmeier, M., Steffens, M., Mueller, C.W., Kölbl, A., Reszkowska, A., Peth, S., Horn, R., Kögel-Knabner, I., 2012. Aggregate stability and physical protection of soil organic carbon in semi-arid steppe soils. European Journal of Soil Science63, 22–31.

[53] Yamashita, T., Flessa, H., John, B., Helfrich, M., Ludwig, B., 2006. Organic matter in density fractions of water-stable aggregates in silty soils: effect of land use. Soil Biology and Biochemistry38, 3222–3234.

[54] Yang, Y., Liu, B.R. 2019. , Testing relationship between plant productivity and diversity in a desertified steppe in northwest China. PeerJ7, e7239.

[55] Yu, L.F., Chen, Y., Sun, W.J., Huang, Y., 2019. Effects of grazing exclusion on soil carbon dynamics in alpine grasslands of the Tibetan Plateau. Geoderma353, 133–143.

[56] Yu, P.J., Wang, H.Q., Hu, J., Shi, W.Y., Xia, X.Y., Sun, X.Z., Tang, H.Y., Huang, Y.X., 2024. Vegetation degradation reduces aggregate associated carbon by reducing both labile and stable carbon fraction in Northeast China. Science of the Total Environment954, 176789.

[57] Zhang, C., Li, J., Wang, J., Liu, G.B., Wang, G.L., Guo, L., Peng, S.Z., 2019a. Decreased temporary turnover of bacterial communities along soil depth gradient during a 35-year grazing exclusion period in a semiarid grassland. Geoderma351, 49–58.

[58] Zhang, M., Li, D.P., Wang, X.Y., Abulaiz, M., Yu, P.J., Li, J., Zhu, X.P., Jia, H.T., 2021. Conversion of alpine pastureland to artificial grassland altered CO₂ and N₂O emissions by decreasing C and N in different soil aggregates. PeerJ9, e11807.

[59] Zhang, N.N., Sun, G., Zhong, B., Wang, E.T., Zhao, C.Z., Wang, Y.J., Cheng, W., Wu, N., 2019b. Impacts of wise grazing on physicochemical and biological features of soil in a sandy grassland on the Tibetan Plateau. Land Degradation & Development30, 719–729.

[60] Zhang, W.B., Li, J., Struik, P.C., Jin, K., Ji, B.M., Jiang, S.Y., Zhang, Y., Li, Y.H., Yang, X.J., Wang, Z., 2023. Recovery through proper grazing exclusion promotes the carbon cycle and increases carbon sequestration in semiarid steppe. Science of the Total Environment892, 164423.

[61] Zhao, L.P., Su, J.S., Wu, G.L., Gillet, F., 2011. Long-term effects of grazing exclusion on aboveground and belowground plant species diversity in a steppe of the Loess Plateau, China. Plant Ecology and Evolution144, 313–320.

[62] Zhou, Z.C., Gan, Z.T., Shangguan, Z.P., Dong, Z.B., 2010. Effects of grazing on soil physical properties and soil erodibility in semiarid grassland of the Northern Loess Plateau (China). CATENA82, 87–91.

[63] Zhou, Z.Y., Sun, O.J., Huang, J.H., Li, L.H., Liu, P., Han, X.G., 2007. Soil carbon and nitrogen stores and storage potential as affected by land-use in an agro-pastoral ecotone of northern China. Biogeochemistry82, 127–138.

[64] Zhu, R.H., Zheng, Z.C., Li, T.X., He, S.Q., Zhang, X.Z., Wang, Y.D., Liu, T., 2019. Effect of tea plantation age on the distribution of glomalin-related soil protein in soil water-stable aggregates in southwestern China. Environmental Science and Pollution Research26, 1973–1982.

RIGHTS & PERMISSIONS

Higher Education Press