Effect of Nitrogen Level and Plowing Frequency on Sesame (Sesamum indicum L.) Yield and Yield Component in Western Oromiya, Ethiopia

The field experiment was carried out at Haro Sabu on station, Guliso and Igu kofale location during cropping season of 2014/15 with the objectives of determining the optimum of nitrogen and plowing frequency required for high yield of sesame. The experiment was laid out in RCBD with three replication in factorial combination of six nitrogen level (0, 8, 18, 28, 38, 48kg N ha-1) and three plowing frequency (one, two and three times) on sesame (Dicho) variety. Plant height was significantly (P < 0.05) affected by Nitrogen level and highly significantly (P < 0.01) affected by plowing frequency. The highest plant height (91.20cm) and (91.18 cm) was recorded from 48 kg N ha-1 and three times plowing frequency, respectively. Number of branch per plant was significantly (P<0.05) affected by nitrogen level. The highest number of branches per plant (4.40) was obtained from 38kg N- ha. Number of pod per plant was significantly (P<0.05) affected by Nitrogen level and Plowing frequency. The highest number of pod per plant (125.79) and (124.57) was recorded from 8kgN-ha and three times plowing frequency, respectively. Grain yield was highly significantly (P<0.01) affected by Nitrogen level and plowing frequency. The lowest grain yield (3.40 quintal ha-1) was obtained from 0kg N ha-1. The highest (5.41 quintal ha-1) grain yield was obtained from three time plowing frequency. Partial budget analysis of N fertilizer rates indicted that higher marginal rate of return (1351%) was found by applying 8 kg N ha-1. Therefore Applications of 8 kg ha-1 of nitrogen and three times plowing frequency, was recommended for increased yield and better economic returns to sesame growers at study area. Keywords: Nitrogen level, plowing frequency, Sesamum indicum L