Effect of Nitrogen Fertilizer Rates on Seed Yield and Oil Quality of Linseed (Linum Usitatissimum L.) Varieties in Welmera District, Central Highland of Ethiopia

Abstract

Linseed (Linum usitatissimum L.) is one of the most important oilseed crop in the central highlands of Ethiopia. However, poor soil fertility management and lack of improved varieties affect its seed yield and oil quality. Therefore, an experiment was conducted to evaluate the effects of nitrogen fertilizer rates on yield, and oil quality of linseed varieties in Welmera district. The experiment was laid out in a randomized completed block design with three replications. The treatments were factorial combinations of three linseed varieties (Bekoji-14, Jeldu, and Kulumsa-1) and five rates of Nitrogen (0, 11.5, 23.0, 34.5, and 46.0 kg N ha-1). The analysis of variance showed that the main effect nitrogen and varieties significantly (P<0.05) affected seed and oil yields, oil content, and fatty acid compositions of linseed. The maximum seed yield (1508 kg ha-1) and oil yield (604.4 Lt ha-1) were recorded from 46 kg N ha-1 with Jeldu variety; while the minimum seed yield (782 kg ha-1) and oil yield (445.8 lt ha-1) were obtained from the control treatment with Bokoji-14 variety. The highest polyunsaturated fatty acids content (linolenic 56.24, oleic 19.43, and linoleic 14.37%) and the optimal range of saturated fatty acids (palmitic 5.82 and stearic 4.89%) were recorded from 46 kg N ha-1 treatment. Moreover, the partial budget analysis also indicated that the maximum net benefit 36,865birr ha-1 with MRR 1738% was obtained from 46 kg N ha-1. Therefore, farmers in the study area can be advised to use Juldu variety with 46 kg N ha-1 for better seed and oil yields with optimal fatty acid composition.