Mixtures of UK Wheat as an Efficient and Environmentally Friendly Source for Bioethanol

Concerns about access to oil supplies have encouraged the exploration of renewable fuel and energy sources. Industrial ecology offers tools to compare the energy implications and benefits of differing strategies, but using botanical sources of raw materials to replace nonrenewable ones also requires appreciation of plant science, especially the variation in genetic potential within species. Whereas cultivation methods determine whether genetic potential is realized, different methods impact the environment to varying degrees. Experience with barley variety mixtures, aimed at reducing chemical input, has shown them to improve yield and reduce disease, while maintaining or even enhancing quality. Yield improvements still occurred in the absence of disease and increased in proportion to the number of component varieties. Because other research showed mixtures to be similarly effective in wheat, a protocol to grow and exploit a complex mixture of soft wheat is proposed, offering a cost‐effective and energy efficient feedstock for a possible bioethanol industry in the United Kingdom. Ethanol would be produced initially from grain, with the straw used for heating or electricity generation. Fertilizer production and use and vehicle fuels have been shown as the main forms of energy consumption in growing a crop, and targets for enhancing the energy balance, by growing mixtures under an integrated farming system, are postulated. A close but negative association between grain protein and alcohol yield is demonstrated and a mixture giving comparable grain yield, but superior alcohol yield, to its best component is identified. Mixing varieties differing in plant morphology may also increase total biomass yield and, therefore, the energy generated from the crop. Pesticide reduction has another positive, though small, effect on the energy balance, from using mixtures. Eliminating prophylactic spraying also reduces vehicle fuel consumption, and may provide the low‐toxicity benefits of organic agriculture without the yield penalty. A range of alternative uses for straw and other by‐products is also discussed.