Effect of nitrogen and sulphur fertilizer levels on growth, yield and oil content of Linseed (Linum usitatissimum L.) in Sinana, South-Eastern Ethiopia

Abstract

The experiment was conducted on research field of Sinana Agricultural Research Center (SARC), in the highlands of Bale, South-eastern Ethiopia during the main cropping season of 2013 to investigate the effect of nitrogen and sulphur on growth, yield and oil content of linseed. A factorial combination of four rates of N (0, 23, 46, 69 kg ha^-1) with four rates of S (0, 20, 40 and 60 kg  ha^-1) was applied in randomized complete block in three replications. Analysis of variance revealed that the main effect of nitrogen significantly affected all tested parameters except for days to 50% emergence, number of seeds per capsule and stand count per meter square. In these study, most of yield and yield components of the crop lacked significant response to the application of sulphur. This might be due to the fact that sulphur content of the soil of the study site was medium. On the other hand, the interaction effect between nitrogen and sulphur was only significant for days to 50% emergence. Linseed crop grown without nitrogen application exhibited the highest seed oil content (40.7%). The economic analysis revealed that the highest net return of Birr 31980 ha^-1 and the highest marginal rate of return 5045.21% were obtained from the treatment that received 23 kg N ha^-1. Therefore, for farmers cultivating linseed in Sinana and areas with the same soil chemical and physical conditions, application of 23 kg N ha^-1 is sufficient for obtaining optimum seed and oil yield of the crop, with no need to apply sulphur as a fertilizer. However, to come up with a conclusive recommendation, the experiment should be repeated over seasons and locations.