Influence of crop management on the agronomic and combustion properties of spelt (Triticum spelta L.)

The objective of this research was to determine the effects of cultivar and nitrogen fertilization on grain yield for human consumption and on the quantitative and qualitative value of straw as solid biofuel for combustion. The research was carried out in field trials established in the north-west of Croatia at the University of Zagreb, Faculty of Agriculture, during two growing seasons. The research included three cultivars (Nirvana, BC Vigor and Ostro) and three nitrogen topdressing rates: N1 - no nitrogen topdressing, N2 - application of 25 kg nitrogen ha(-1) by one topdressing and N3 - application of 50 kg nitrogen ha(-1) by two topdressings. The highest hulled grain yield was obtained with the cultivar Nirvana and the N3 treatment. High straw and straw energy yields were obtained with the N2 and N3 treatments. Higher straw and straw energy yields were obtained in the growing season with higher precipitation. The ultimate and proximate analysis showed that researched cultivars differed only in ash and moisture content. Nitrogen fertilization had a predominantly positive effect on the combustion properties of the straw, as the carbon and hydrogen content increased, and the oxygen and ash content decreased. The combustion properties also depended on the weather conditions and their interaction with cultivars and nitrogen fertilization. These results indicate that nitrogen fertilization, even at a minimal dose, is an obligatory agrotechnical measure for high yields and good combustion properties when spelt is grown for dual purposes.