TY - JOUR
T1 - Sensitivity of soil organic carbon to grazing management in the semi-arid rangelands of south-eastern Australia
AU - Orgill, S. E.
AU - Waters, C. M.
AU - Melville, G.
AU - Toole, I.
AU - Alemseged, Y.
AU - Smith, W.
N1 - Includes bibliographical references.
PY - 2017/2/21
Y1 - 2017/2/21
N2 - This study compared the effects of grazing management on soil organic carbon (OC) stocks in the semi-arid rangelands of New South Wales, Australia. A field survey was conducted at three locations (Brewarrina, Cobar-North and Cobar-South), with paired sites of long-term (>8 years) rotational grazing management and continuously grazed pastures (either set stocked or no stocking). At each location, soil OC, carbon (C) fractions, soil nitrogen (N) and microsite and site factors (including ground cover and woody vegetation) were measured. The control of total grazing pressure (TGP) through rotational grazing and exclusion fencing did not increase soil C stocks compared with continuous grazing for the majority of comparisons. However, in some parts of the landscape, higher soil C stock was found with TGP control, for example on the ridges (21.6 vs 13.3 t C ha-1 to 0.3 m). Cstocks increased with litter and perennial ground cover and with close proximity to trees. At Brewarrina, C stocks were positively affected by perennial plant cover (P < 0.001) and litter (P < 0.05), whereas at Cobar-North and Cobar-SouthCstocks were positively affected by the presence of trees (P < 0.001), with higherCstocks in close proximity to trees, and with increasing litter cover (P < 0.01). The present study demonstrates that natural resource benefits, such as increased perennial cover, can be achieved through controllingTGPin the rangelands but increases in soilC may be limited in certain parts of the landscape. These findings also highlight that interactions between managed and unmanaged TGP and microsite factors, such as ground cover and proximity to woody vegetation, need to be considered when evaluating the role of changed grazing management on soil C.
AB - This study compared the effects of grazing management on soil organic carbon (OC) stocks in the semi-arid rangelands of New South Wales, Australia. A field survey was conducted at three locations (Brewarrina, Cobar-North and Cobar-South), with paired sites of long-term (>8 years) rotational grazing management and continuously grazed pastures (either set stocked or no stocking). At each location, soil OC, carbon (C) fractions, soil nitrogen (N) and microsite and site factors (including ground cover and woody vegetation) were measured. The control of total grazing pressure (TGP) through rotational grazing and exclusion fencing did not increase soil C stocks compared with continuous grazing for the majority of comparisons. However, in some parts of the landscape, higher soil C stock was found with TGP control, for example on the ridges (21.6 vs 13.3 t C ha-1 to 0.3 m). Cstocks increased with litter and perennial ground cover and with close proximity to trees. At Brewarrina, C stocks were positively affected by perennial plant cover (P < 0.001) and litter (P < 0.05), whereas at Cobar-North and Cobar-SouthCstocks were positively affected by the presence of trees (P < 0.001), with higherCstocks in close proximity to trees, and with increasing litter cover (P < 0.01). The present study demonstrates that natural resource benefits, such as increased perennial cover, can be achieved through controllingTGPin the rangelands but increases in soilC may be limited in certain parts of the landscape. These findings also highlight that interactions between managed and unmanaged TGP and microsite factors, such as ground cover and proximity to woody vegetation, need to be considered when evaluating the role of changed grazing management on soil C.
KW - Carbon sequestration
KW - Ground cover
KW - Nitrogen
KW - Particulate organic carbon
KW - Total grazing pressure.
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U2 - 10.1071/RJ16020
DO - 10.1071/RJ16020
M3 - Article
AN - SCOPUS:85035024388
SN - 1036-9872
VL - 39
SP - 153
EP - 167
JO - Rangeland Journal
JF - Rangeland Journal
IS - 2
ER -