Soil Organic Carbon Increases in Semi-Arid Regions while it Decreases in Humid Regions Due to Woody-Plant Encroachment of Grasslands in South Africa

    Mureva, A and Ward, D and Pillay, T and Chivenge, P and Cramer, M (2018) Soil Organic Carbon Increases in Semi-Arid Regions while it Decreases in Humid Regions Due to Woody-Plant Encroachment of Grasslands in South Africa. Scientific Reports (TSI), 8 (1). pp. 1-12. ISSN 2045-2322

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    Abstract

    Grasslands and savannas are experiencing intensive land-cover change due to woody plant encroachment. This change in land cover is thought to alter soil carbon (C) and nitrogen (N) storage in these ecosystems. Some studies have reported a negative correlation between soil C and N and mean annual precipitation while others have indicated that there is no relationship with mean annual precipitation. We quantified the changes in C and N pools and δ13C and δ15N values to a depth of 1 m in pairs of encroached and adjacent open grassland sites along a precipitation gradient from 300 mm to 1500 mm per annum in South Africa. Our study showed a negative correlation between changes in soil organic C stocks in the 0–100 cm soil layer and mean annual precipitation (MAP). The most humid site (1500 mm MAP) had less C in shrub-encroached sites while the drier sites (300–350 mm MAP) had more C than their paired open grasslands. This study generally showed soil organic C gains in low precipitation areas, with a threshold value between 750 mm and 900 mm. Our threshold value was higher than that found in North America, suggesting that one cannot extrapolate across continents.

    Item Type: Article
    Divisions: Research Program : East & Southern Africa
    CRP: UNSPECIFIED
    Uncontrolled Keywords: Soil Organic Carbon, Semi-Arid Regions, Woody-Plant Encroachment, Grasslands, South Africa, Grasslands, savannas, woody plant encroachment, soil carbon, nitrogen storage
    Subjects: Others > Semi-Arid Tropics
    Others > Africa
    Depositing User: Mr Ramesh K
    Date Deposited: 15 Nov 2018 09:42
    Last Modified: 15 Nov 2018 09:47
    URI: http://oar.icrisat.org/id/eprint/10940
    Official URL: http://dx.doi.org/10.1038/s41598-018-33701-7
    Projects: UNSPECIFIED
    Funders: National Research Foundation, German BMBF
    Acknowledgement: UNSPECIFIED
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