Schipper, L.A., Mudge, P.L., Kirschbaum, M.U.F., Hedley, C.B., Golubiewski, N.E., Smaill, S.J., Kelliher, F.M. (2017). A review of soil carbon change in New Zealand’s grazed pastures. New Zealand Journal of Agricultural Research (Accepted).
Soil organic matter is a potential sink of atmospheric carbon (C) and critical for maintaining soil quality. We reviewed New Zealand studies of soil C changes after conversion from woody vegetation to pasture, and under long-term pasture. Soil C increased by about 13.7 tC ha–1 when forests were converted to pasture. Under long-term pasture on flat land, soil C had declined in Allophanic, Gley and Organic Soils by 0.54, 0.32 and 2.9 tC ha-1 y-1, respectively. Pasture soils on stable midslopes of hill country gained 0.6 tC ha-1 y-1. Phosphorus fertiliser application did not change C stocks. Irrigation decreased carbon by 7 tC ha–1. Carbon losses during pasture renewal ranged between 0.8-4.1 tC ha–1. Some evidence suggests tussock grasslands can gain C when fertilised and not overgrazed. When combined to the national scale, different data sets suggest either no change or a gain of C, but with large uncertainties.
Keywords: carbon, soil, pasture, management, land use, New Zealand.
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