Effect of Nitrogen and Phosphorus Fertilizers on Growth, Yield and Yield Components of Black Cumin (Nigella sativa L.) at Konta District, South West Ethiopia

Abstract

Field experiment was conducted at Duka, Konta district to determine the effect of Nitrogen (N) and Phosphorous (P) fertilizers on growth, yield and yield components of black cumin. Five levels of N (0, 15, 30, 45 and 60 kg haG1 in the form of urea) and three levels of P (0, 20, 40 kg haG1 in the form of TSP), arranged in RCB design with three replications. Results indicated that interaction of N and P highly significantly (p<0.01) influenced the different growth and yield parameters except for 1000 seed weight. The highest seed yield (1336.7 kg haG1 was obtained from 60/40 kg N P haG1 . Highest number of pods per plant (45.9) was obtained from 60 kg N haG1 and 40 kg P haG1 interactions. The tallest plants (72.5 cm) were measured o plots fertilized at the rate of 60/40 kg N PhaG1 . The highest number of branches (46.1) was obtained from the interaction effect of 60/40 kg N P haG1 . The highest numbers of seeds per pod (91.6) was achieved at treatment combination of 60/40 kg N P haG1 followed by 88.4 seeds by the treatment combination of 60/20 kg N P haG1 . The highest harvest index (20.8%) was obtained from the treatment that received 60/40 kg NP followed by 20.5%, which received 45/20 kg, N P haG1 interactions and the lowest harvest index (15.1%) was recorded from the treatment that received 15 and 0 kg NP interaction. The longest days to 50% flowering (86.7 days) were observed for the treatment that received 60/40 kg N P haG1 . However, the shortest flowering days (75.5) days were for the control treatment. Partial budget analysis has shown that two treatment combinations of (NP haG1 ) were found to be economically viable with marginal rate of revenue beyond the minimum acceptable level (150%). The highest MRR (%) was obtained with the interaction effect of 45/40 kg NP haG1 with marginal rate of revenue (1272.2%) for net benefit 15254.1 birr, followed by the interaction effect of 15/20 kg NP haG1 with marginal rate of revenue (485%) for net benefit 10325 birr over the control with a net benefit 8595.0 birr. Since the experiment was conducted at one place and only for one cropping season, it will not be appropriate to arrive at a strong recommendation. However, as a recommendation, growers can be advised to use a combination of 45/40 kg NP haG1 followed by 15/20 Kg N P2O5 haG1 for black cumin production in the area.