Production costs and residues evaluation of Crambe abyssinica as an energy feedstock

In Europe, like in other parts of the world, plant species predisposed for use as energy crops are searched for. Among the oil plants grown in European countries, rape is most important although rape oil is mainly a food product. On the other hand, Crambe abyssinica is an oil plant species which is not used to make human food or animal feeds. Besides, Crambe abyssinica oil has a high content of erucic acid, hence it has the potential to be processed into many different products in the power generation or chemical industries. This paper documents results of a field experiment conducted in north-eastern Poland, at the Experimental Station of the University of Warmia and Mazury in Olsztyn, located in Łężany (53°35’ N, 20°36’ E). The aim of this experiment was to determine costs of production of Crambe abyssinica grown in two variants (with and without herbicides). In addition, the quality of by-products (straw and cake) as energy feedstocks was evaluated. Costs of production of Crambe abyssinica seeds in the variant with herbicides were nearly 140€•ha-1 higher than in the variant without herbicides. The yield of pure seeds was by over 110kg•ha-1 higher in the herbicide-treated variant than in the treatment without weed control. However, the yield of straw was higher on fields without application of herbicides, but that straw had a higher moisture content due to the presence of weeds. The lower heating value of crambe straw was 15.3MJ•kg-1 on average and the straw content of ash was 5.68% D.M. The cake obtained from the crop had a much higher lower heating value (21.95MJ•kg-1) and ash content 6.41% D.M. Moreover, it was found to contain much more carbon and hydrogen, as well as five-fold more sulfur than straw.