Soil Carbon Stocks and Carbon Stability in a Twenty-Year-Old Temperate Plantation
- Émilie Maillarda,
- David Paréb and
- Alison D Munson *a
Afforestation and reforestation are considered important tools for mitigating fossil fuel emission; however, establishment of plantations necessarily involves several silvicultural treatments that may influence soil organic C sequestration and, potentially, its relative stability. An experimental design established 20 yr ago, consisting of plantations of white pine (Pinus strobus L.) and white spruce [Picea glauca (Moench) Voss] was used to determine midterm impacts of blade scarification, fertilization, application of an herbicide, and tree species on soil C stocks and on the fraction of labile C determined by measurement of C mineralization on laboratory incubations. Twenty years after treatment, blade scarification had the greatest effect on soil organic C stock and stability. Carbon content was 54.2% lower in the F/H layer (equivalent to Oi and Oe/Oa layers) of blade-scarified plots compared with plots without blade scarification. Effects on the mineral soil layers were less obvious and partly mitigated by the addition of fertilizer on the surface. Blade scarification affected the general quality of C in the F/H layer because it significantly increased by 21.1% the fraction of labile C to total C; nevertheless, labile C content was 51.9% lower in the blade-scarified treatment. Vegetation control by herbicide as well as tree species had minor effects on C stocks and stability. A 9.0% decrease in mineral soil C content was observed with vegetation control. The F/H layer C concentration was 18.6% higher under white spruce than under white pine but these differences did not lead to a difference in C content. The small effects of treatments on surface mineral soil C could be explained by the limited capacity of this coarse-textured soil to sequester more silt- and clay-associated C.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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