Carbon storage in Orchards
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- PhD, School of Environment, Natural Resources and Geography
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Abstract
Current concern over climate change requires that carbon (C) sources and sinks within managed landscapes are quantified so that they can be actively managed to help reduce net greenhouse gas (GHG) emissions. While some data exist for C storage in grassland and forests, potential for C sequestration in orchards is largely unknown. Initial C inventory studies in apple (Malus) orchards determined that C sequestration in soil and trees increased with stand age. This result conflicts with current commercial management which requires trees to be replaced every 30 years to reduce disease risk. The grubbing-out process, where complete orchard trees are removed, liberated approximately 0.01 t C ha-1 from the soil, which is very small in comparison to the C loss from removal of biomass (up to 25 t C ha-1 above-ground, ca. 5 t C ha-1 below-ground) and that held in the soil (ca. 80 t C ha-1 ). The incorporation of biochar produced from the grubbed-up apple trees offers orchards the opportunity to enhance C storage. However long-term impacts of biochar amendments on the environment remain unknown. An experiment was established to monitor Bramley apple trees in varying levels of biochar amendment (0, 5, 25 and 50 t ha-1). The results suggested that biochar had no negative effects on tree productivity and soil quality. Investigations into density, surface area, pore size distribution and water sorption were carried out to characterise the Malus-derived char. Orchard carbon footprints have been carried out to determine orchard GHG emissions and identify potential areas of C savings. Findings suggest that footprints of UK apple production are comparatively low, ranging from 0.037 to 0.182 kg CO2e per kg produce. In conclusion, there is potential within UK orchards to sequester C; full C budgets need to be carried out to determine annual C sequestration.
Details
Original language | English |
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Award date | 4 Nov 2013 |