Abstract
In the UK and other temperate regions, short rotation coppice (SRC) and Miscanthus x giganteus (Miscanthus) are two of the leading ‘second-generation’ bioenergy crops. Grown specifically as a low-carbon (C) fossil fuel replacement, calculations of the climate mitigation provided by these bioenergy crops rely on accurate data. There are concerns that uncertainty about impacts on soil C stocks of transitions from current agricultural land use to these bioenergy crops could lead to either an under- or overestimate of their climate mitigation potential. Here, for locations across mainland Great Britain (GB), a paired-site approach and a combination of 30-cm- and 1-m-deep soil sampling were used to quantify impacts of bioenergy land-use transitions on soil C stocks in 41 commercial land-use transitions; 12 arable to SRC, 9 grasslands to SRC, 11 arable to Miscanthus and 9 grasslands to Miscanthus. Mean soil C stocks were lower under both bioenergy crops than under the grassland controls but only significant at 0–30 cm. Mean soil C stocks at 0–30 cm were 33.55 ± 7.52 Mg C ha−1 and 26.83 ± 8.08 Mg C ha−1 lower under SRC (P = 0.004) and Miscanthus plantations (P = 0.001), respectively. Differences between bioenergy crops and arable controls were not significant in either the 30-cm or 1-m soil cores and smaller than for transitions from grassland. No correlation was detected between change in soil C stock and bioenergy crop age (time since establishment) or soil texture. Change in soil C stock was, however, negatively correlated with the soil C stock in the original land use. We suggest, therefore, that selection of sites for bioenergy crop establishment with lower soil C stocks, most often under arable land use, is the most likely to result in increased soil C stocks.
Original language | English |
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Pages (from-to) | 1046-1060 |
Number of pages | 15 |
Journal | Global Change Biology. Bioenergy |
Volume | 8 |
Issue number | 6 |
Early online date | 16 Oct 2015 |
DOIs | |
Publication status | Published - 1 Nov 2016 |
Bibliographical note
AcknowledgementsWe are exceptionally grateful to all the land owners who have granted us access to sample their fields. Kate Farrall, Jessica Adams, Neil Mullinger, Adam Dargan and Lou Walker for field and laboratory assistance. Pete Henrys (Centre for Ecology & Hydrology) for statistical guidance. This work was part of the Ecosystem Land-Use Modelling (ELUM) project, which was commissioned and funded by the Energy Technologies Institute.
Keywords
- bioenergy
- Carbon Stocks
- land-use change
- Miscanthus
- soil carbon
- SRC willow