Elemental Concentrations in Triticale Straw, a Potential Bioenergy Feedstock

Triticale (x Triticosecale Wittmack) is a small cereal grain crop produced for livestock feed and forage on more than three million hectares (ha) worldwide including 344 000 ha in the U.S.A. After the grain is harvested, triticale straw residue could provide feedstock for bioenergy production in many regions of the world, but high concentrations of certain elements, including silicon (Si), potassium (K), and chlorine (Cl) that are characteristic of other cereal straws, their suitability for use in thermochemical conversion technologies. Also, straw harvest is associated with the removal of macro- and micronutrients from crop production systems and may impact the long-term sustainability of residue removal. We quantified the concentrations of seven elements in chaff, grain, leaves, and stems harvested from eight triticale cultivars grown in western Oregon to determine whether there was genotypic variability that may impact the concentrations of these elements. On average, harvest of the chaff, leaves, and stems combined removed 9.6 g of nitrogen (N), 5.3 g of phosphorus (P), and 80 g of K kg(-1) of biomass Harvest of the grain alone removed 21.7, 3.1, and 4.8 g kg(-1) N, P, and K, respectively. The Si content of cliff and leaves ranged from 17 583 to 37 163 mg kg(-1) of biomass. Straw from the genotype Taza contained the least amount of Si. The variability and range of concentrations of elements among these cultivars suggests that genetic approaches would, not only modify the composition of macro- and micro nutrients but also would improve the utility of triticale straw as bioenergy feedstock. Chaff, leaves, and stem components of triticale are relatively uniform in their energy contents that range between 17.51 and 17.96 MJ kg(-1). Selective harvest of triticale straw components could reduce the content of Si and other minerals that impact the use of this biomass in thermochemical conversion processes.