Abstract
A systematic review and meta-analysis were used to assess the current state of knowledge and quantify the effects of land use change (LUC) to second generation (2G), non-food bioenergy crops on soil organic carbon (SOC) and greenhouse gas (GHG) emissions of relevance to temperate zone agriculture. Following analysis from 138 original studies, transitions from arable to short rotation coppice (SRC, poplar or willow) or perennial grasses (mostly Miscanthus or switchgrass) resulted in increased SOC (+5.0 ± 7.8% and +25.7 ± 6.7% respectively). Transitions from grassland to SRC were broadly neutral (+3.7 ± 14.6%), whilst grassland to perennial grass transitions and forest to SRC both showed a decrease in SOC (−10.9 ± 4.3% and −11.4 ± 23.4% respectively). There were insufficient paired data to conduct a strict meta-analysis for GHG emissions but summary figures of general trends in GHGs from 188 original studies revealed increased and decreased soil CO2 emissions following transition from forests and arable to perennial grasses. We demonstrate that significant knowledge gaps exist surrounding the effects of land use change to bioenergy on greenhouse gas balance, particularly for CH4. There is also large uncertainty in quantifying transitions from grasslands and transitions to short rotation forestry. A striking finding of this review is the lack of empirical studies that are available to validate modelled data. Given that models are extensively use in the development of bioenergy LCA and sustainability criteria, this is an area where further long-term data sets are required.
Highlights
Over the last three hundred years, more than half of the global land surface has been impacted by human activity [1,2]
Studies were eligible if they documented a land conversion not strictly for use as bioenergy, but used similar land management practices as would be used for bioenergy cultivation. (4) study locations were relevant to a temperate climate i.e. within the 23.5 and 66.5 latitudinal band and (5) the species were inclusive of 1st generation (1G) and 2G bioenergy crops (Table 1), but only those able to be cultivated in a temperate region
Contrary to traditional statistical tests, in the case of a metaanalysis, the magnitude of the effect size is more important for interpretation of the results than the p-value [33]. p-values are able to indicate, with 95% confidence, that the result differs to the null hypothesis, and when read are rarely considered with the sample size
Summary
Over the last three hundred years, more than half of the global land surface has been impacted by human activity [1,2]. Land Use Change (LUC) is a major driver of global environmental change [3,4] and an important driver of increased greenhouse gas (GHG) emissions, contributing to the 180 ± 80 Pg C rise in atmospheric CO2 between 1750 and 2011 [5]. There is an urgent need to mitigate the impacts of LUC, through sustainable land management strategies that include renewable energy technologies such as bioenergy, which has the potential to provide both carbon sequestration and a displacement of fossil-based fuels. Renewable energy targets across Europe and in both national [12] and international [13] future energy scenarios, suggest a central role for bioenergy where 10e20% of primary energy supply is provided from green plants in some form, including to generate electricity, heat and liquid transport fuel [14]. It is important to quantify the direct impacts of LUC for GHG balance, SOC and other landscape scale effects, so that appropriate land management strategies can be put in place
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
