Carbon stocks in riparian buffer systems at sites differing in soil texture, vegetation type and age compared to adjacent agricultural fields in southern Ontario, Canada
2020
Vijayakumar, Sowthini | Bazrgar, Amir Behzad | Coleman, Brent | Gordon, Andrew | Voroney, Paul | Thevathasan, Naresh
In any given watershed, riparian buffer systems (RBSs) can influence terrestrial carbon (C) sequestration and potentially enhance terrestrial C sinks. This study looked at the effects of soil texture, vegetation type and age on C stock sequestration in eight RBSs located within the Grand River Watershed (GRW), southern Ontario, Canada and compared the C stock with adjacent agricultural fields. Soil organic carbon (SOC) stocks on an equivalent mass basis were significantly higher (p<0.05) in mature buffers (192.7 Mg C ha⁻¹) compared to adjacent agricultural fields (corn [Zea mays] –soybean [Glycine max] –wheat [Triticum aestivum] rotation), at 0-30 cm soil depth (88.2 Mg C ha⁻¹), irrespective of soil texture and vegetation type of RBS. Sixty-year old deciduous tree buffers on clayey soils had the highest SOC concentration (5.94 %, p<0.05) at 0-30 cm soil depth while the young six-year old coniferous tree buffers on loamy soil had the lowest SOC concentration (2.87%). In mature deciduous [major species; sugar maple (Acer saccharum) and ash (Fraxinus excelsior)] buffers, biomass C stocks were 247 Mg C ha⁻¹, which is up to two and half times greater than mature coniferous [major species; eastern white cedar (Thuja occidentalis) and white pine (Pinus strobus)] buffers (100 Mg C ha⁻¹). Overall results support that increasing RBS within Ontario watershed areas can enhance C stocks and may contribute to Canada’s climate change mitigation efforts. In the context of riparian areas, deciduous species should be promoted over coniferous species to obtain higher terrestrial C sequestration within Ontario watersheds.
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