Soil carbon storage in the root zone of a perennial grass pasture
Ward, P., Wocheslander, R., Ferris, D., Revell, C. and Harper, R. (2015) Soil carbon storage in the root zone of a perennial grass pasture. In: Proceedings of the 17th Australian Agronomy Conference, 20 - 24 September, Hobart, Tas, Australia
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Carbon sequestration in soils is an issue of international significance, as soils represent a large carbon pool and can be a major sink for atmospheric carbon dioxide. In southern Australia, soil carbon under agricultural land uses has received attention, particularly in relation to the potential for perennial plants to sequester carbon. Although considerable attention has been applied to carbon sequestration associated with reforestation, there has been less work associated with perennial pastures. It can be argued that farmers are more likely to change pasture than undertake reforestation, thus if carbon mitigation via the land sector is to occur over large areas, the dynamics of carbon under perennial pastures needs assessment. Standard soil testing for carbon stocks extends to a depth of 0.3 m whereas perennial pastures have the potential to grow roots much deeper than this, and potentially can have impacts on soil carbon storage to the full depth of the root zone. In this research we measured soil carbon to a depth of 4.0 m under a replicated trial on a deep sandy soil including plots of Gatton panic (Megathyrsus maximus) and plots of a barley/lupin rotation, five years after commencement of the trial. Soil water measurements suggested a maximum rooting depth for the pasture of 3.5 m, and 1.5 m for the annual crops. Despite differences in root depth, there were no significant differences in soil carbon between the two land uses. However, total soil carbon storage was considerably higher (44 t C/ha) when measured to a depth of 4 m compared with the standard 0.3 m depth (23 t C/ha).
|Publication Type:||Conference Paper|
|Murdoch Affiliation:||School of Veterinary and Life Sciences|
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