Crop residues, including wheat straw and corn stover, are a feedstock for the production of cellulosic biofuel that could contribute to meeting advanced biofuel targets and decarbonization goals for the transport sector. However, there are concerns about potential negative environmental impacts of crop residue harvest for biofuel production. In particular, incentivizing the collection and use of crop residues that otherwise would have been retained in fields can affect soil carbon and soil quality.
This study presents a review and meta-analysis of experimental findings on the impact of crop residue management on soil carbon in the European Union. While many studies on crop residue harvesting have been focused on corn stover in the United States, much less is known about these impacts in the European context. This study seeks to understand how much crop residue can be sustainably harvested from European fields and what physical and management factors affect sustainable removal rates. In any case, it is clear that sustainable residue removal rates should be determined based on local conditions and practices.
Our assessment supports the idea that, in many cases, some amount of crop residue can be harvested without negative impacts on soil carbon. There is thus the potential for considerable scaling up of Europe’s cellulosic biofuel industry using this resource; biofuel produced from crop residues could deliver greenhouse gas reductions while supporting sustainable agriculture.