Abstract:
Black cumin (Nigella sativa L.), is an annual, aromatic and medicinal spice. The seed is an important condiment for seasoning foods. It is also an important export spice next to ginger in the country. However, productivity is low in the study area due to poor soil fertility management and absence of improved cultivars. To halt this difficulty, a couple of improved varieties were released at national level; but not yet been tested in study area. Therefore, this experiment was aimed to test response of black cumin varieties to different NPSB fertilizer rates during March–August 2023 cropping season at Debube Ari wereda, South Omo Zone. The treatments were three black cumin varieties (Dershaye, Silingo and Eden) and four NPSB fertilizer rates (0, 50, 100 and 150 kg/ha) arranged factorial in triplicate. It designed in split plot with NPSB fertilizer and black cumin varieties assigned as main and sub plot, respectively. The collected data on phenology, plant growth, yield component, yields, and quality parameters were subjected to Analysis of Variance (ANOVA) using Statistix10 computer software version 10.0.0.2. The result showed that day to 50% flowering, number of seed capsule-1, and grain yield plant-1 were significantly (p<0.01) affected by NPSB rate only, and plant height, number of secondary branch, grain yield, fixed oil, were significantly (p<0.01) affected by NPSB and varieties. The highest plant height (63.82cm), longest root length (26.9), maximum number of branch (9.5) recorded in a treatment received 150 NPSB. The highest number of seed capsule-1 (105.15), grain yield plant-1(8.8g) and total grain yield (1,070.8Kg ha-1) were obtained with Silingo variety. The highest number capsule per plant (33.27) was recorded on variety Silingo received 100kg NPSB. Moreover, the highest crude protein (27.47%) and essential oil (0.86%) were obtained in a 150 kg NPSB ha-1. In addition highest fixed oil (39.28) and crude protein (22.26) was obtained on Eden variety. Total grain yield was highly significantly correlated to all plant growth and yield parameters. The best marginal rate of return (8,700%) was obtained in 100 kg NPSB ha-1 with variety Silingo. Therefore, it can be concluded that applying 100kg NPSB ha-1 using variety silingo was found to be economical for smallholder farmers producing black cumin in the study area. Thus, this variety can be recommended to the study area with application of 100 kg NPSB ha-1. However, testing over different locations and season is important.
