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Integrated cropping systems of cereals and dedicated annual lignocellulosic crops
Today most of the feedstock used to produce advanced biofuels is derived from woody biomass and residues such as cereal straw. Agricultural residues are an abundant and widely available resource, nonetheless, the availability and the price of cereal straw at local level is influenced by climatic conditions and by the demand in competing markets. Therefore, in a scenario of increasing demand of biofuels, it is important to diversify the feedstock base for industrial plants that require a constant supply of biomass in the range of tens or hundreds thousand tons, and to complement the supply of agricultural biomass residues with other feedstock options. Dedicated lignocellulosic crops can help to diversify the feedstock base and increase the security of supply for advanced biofuel plants. The REDII allows the production of low-ILUC risk feedstock on abandoned, marginal and unused land. It also allows the use of crops grown before or after the main crops (double cropping), to produce nonfood cellulosic material, without triggering demand for additional land. At least two thirds of the arable land in EU27 and UK is dominated by conventional crop rotations, mainly wheat-maize-fallow, that negatively affect soil-health in the long-term, and require a large input of agrochemicals and fertilizers to sustain the crop productivity.
Enlarging the rotations by introducing annual lignocellulosic crops together with cereals, can also represent a sustainable agronomic practice, that can bring about environmental benefits to the soil structure, its biological activity, water storage capacity, organic matter content, and crop resilience to pests and diseases, as promoted by the CAP and the farm-to-fork strategy. Fiber sorghum, kenaf, sunn hemp and hemp are examples of high-yielding crops that can improve the soil physical and chemical characteristics and help to make a more efficient use of soil resources at the same time. However, there is a limited availability of scientific evidence about the long-term effects of annual biomass crops on the performance and the yield of traditional cereal crops as well as on soil fertility, in multiannual rotational schemes. Filling this gap was one of the main research tasks of BECOOL, carried out by the University of Bologna, CRES and CIEMAT. Together they developed innovative crop rotation systems with the aim to diversify crop rotations and increase the annual quantity of lignocellulosic feedstock per unit of land, avoiding impacts to food production, soil quality, and land use competition.
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