Effects of grazing exclusion on soil organic carbon: Hillslope and soil profile results (an Australian example).


School of Environmental and Life Sciences, Earth Science Building, The University of Newcastle, Callaghan, New South Wales 2308, Australia. Electronic address: [Email]


Soil organic carbon (SOC) is an essential component of the soil-landscape system. It is well recognised that SOC can reduce under some agricultural management practices. In recent years a concerted effort has been undertaken to increase SOC by employing different landscape management practices. Here we compare SOC in a grazing environment to that of an area where cattle have been excluded for over ten years using both a hillslope and whole of soil profile sampling strategy. Surface SOC concentrations (determined by cores) were significantly higher inside the exclusion area when compared to that outside demonstrating a rapid increase in SOC. Whole soil profile (to bedrock) assessment found that SOC decreased with depth both inside and outside of the shelterbelt. While SOC decreased with depth, there were significantly higher surface concentrations inside the exclusion area compared to outside. At depths >20 cm, SOC became increasingly homogenous for both datasets with little difference observed. The results suggest that the influence of the exclusion area on SOC accumulation at the site was only within the top 10-20 cm of the soil profile. The results highlight the importance of soil depth in quantifying SOC within the soil profile and SOC sequestration potential for sites at depth.


Carbon sequestration,Cattle grazing,Exclusion area,Shelterbelts,Soil organic carbon,

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