Biofuels: What Impact on Crop Protection and Seeds Now?
World production of biofuels is dominated by three countries or regions: the US (43%), Brazil (32%) and, less so, the European Union (15%). This will continue to be the case, not only because of respective government policies on biofuels addressing, to various degrees, climate change mitigation, energy security and rural development, but also because of the huge areas of productive land which are needed to provide biomass feedstocks for any significant biofuel production. To date, biofuel feedstocks have been overwhelmingly sourced from materials with high concentrations of carbohydrates or oil in storage organs such as grains and other seeds or roots. This has meant that maize (corn), wheat and sugar beet which could have been used as food and animal feed have been used instead to produce bioethanol. There has been a similar situation in oilseeds, particularly soybeans and oilseed rape (canola), used to produce biodiesel. These are so-called 'first generation' biofuels. However, in general, interest in these crops as feedstocks has been stimulated by 'surplus' production in N. America and Europe. The capacities of feedstocks to produce first generation biofuels are based on typical yields in relevant areas and efficiency of manufacturing. In both cases, the more productive bioethanol and biodiesel feedstocks are crops from tropical regions where more solar energy is fixed by photosynthesis. However, despite only around 2% of the global grain harvest being used for biofuels, recent depletions in the world's food reserves have highlighted the need to move away from the production of first generation biofuels towards 'second generation' biofuels produced from more abundant woody material consisting largely of lignocellulose. Bioethanol produced from lignocellulose is generally referred to as 'cellulosic ethanol'. Biodiesel can also be produced from woody feedstocks by thermochemical processes called biomass to liquid (BTL). There are, however, significant issues around the cost of manufacturing plants, technical feasibility of efficient production and logistics of feedstock supply which mean that for a number of years to come major food crops will still be used to make biofuels. A different issue arises with the two other major crop feedstocks, sugarcane and oil palm. Although they already have established industrial uses, expansion of these crops in Brazil and South-East Asia, respectively, can involve the destruction of valuable natural eco-systems. In addition to these crops, several others are of interest as potentially important feedstocks in Asia. China and Thailand are considering cassava and sweet sorghum for bioethanol; India and China are looking at jatropha for biodiesel. Also, conflicts with food and ecosystems are encouraging research into algal feedstocks, in which land-use, at least, will not be an issue. Overall, the need for sustainable sources of biofuel feedstocks has been repeatedly emphasised. So, where will the biomass needed for first, and later, second generation biofuels come from? Crops, cropping trends, locations and challenges are considered.
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