Response of roselle (Hibiscus sabdariffa L.) to rates of inorganic and farmyard fertilizers in the Sudan savanna ecological zone of Nigeria

Field trials conducted in two rainy seasons at the Usmanu Danfodiyu University, Sokoto, Nigeria, were used to investigate the response of Roselle to organic manure (2.5, 5.0 and 7.5 tons/ha cow dung) and nitrogen (N) fertilizer (25, 50, and 75 kg/ha as urea) applications. The results of the analysis of the experimental data show that calyx yield, pods/plant and seeds/pod responded significantly (P < 0.05) to manure and nitrogen applications in both years (2005 and 2006), while days to 50% flowering did not respond significantly to manure or N-fertilization. However, days to 50% flowering increased with manure, or N-application. For calyx, pod and seed production, application of manure at 7.5 t/ha or N at 75 kg N/ha gave the best result.