Agronomic, economic and environmental analysis of dual-purpose wheat cultivars for bioenergy (PhD)

Abstract

Concerns about climate change and energy supply security have led to a focus on using biofuels to replace oil-based fuels in the transport sector. Second generation biofuels (SGB), which are produced from lignocellulosic material such as wheat straw, are currently being developed.

This project investigated wheat straw supply for SGB production, focusing on the use of dual-purpose cultivars (DPCs) that are optimised to provide for both food and SGB markets. The project consisted of: agronomic assessment of cultivars and management practices for traits associated with a DPC; economic assessment of the value of these DPCs to farmers and costs of straw delivery; life cycle assessment for quantifying environmental burdens associated with straw production from DPCs; and a farmer survey for quantifying current straw supply and potential future straw supply should a new market for straw emerge.

Agronomic trials did not identify any outstanding candidates for use as DPCs from currently grown wheat cultivars or any management practices that would benefit DPC traits. Economic assessment found that straw production costs were lower than the straw price but the overall straw gross margins were much lower than grain gross margins suggesting that grain yield would not be traded off against increased straw yield. Transport costs across the biomass supply chain were slightly lower with the use of DPCs. Environmental burdens for straw production were found to be lower than in other studies but the allocation process had a large influence on the outcomes for this measure. From the survey, 50% of respondents were willing to increase straw yields but even with a very generous price of straw, 21% of respondents would not supply additional straw. The work suggests that straw availability is lower than some current estimates and there is only limited scope to increase straw yield through cultivar selection.