ABSTRACT:Field experiments were conducted during 1998 and 1999 rainy seasons at the Dry Land Teaching and Research Farm of Usmanu Danfodiyo University, Sokoto, to study the response of roselle to farmyard manure, nitrogen and their interaction on the growth and yield of roselle. Treatment consisted of factorial combination of four rates of farmyard manure (0, 2.5, 5.0 and 7.5 t/ha) and four levels of nitrogen fertiliser (0, 25, 50 and 75 kg N/ha) laid out in a randomized complete block design replicated three times. The result showed that there was significant response to applied manure and N-fertiliser on number of leaves up to 5 t/ha manure and 50 kg N/ha. There was no significant increase in calyx yield by raising manure rate from 2.5-7.5 /ha or nitrogen rate from 50 to 75 kg N/ha. Thus, 2.5 t/ha manure and 50 kg N/ha were considered adequate for calyx production in roselle in Sokoto Semi-arid Tropics. However, for maximum number of vegetable leaves additional manure (5-7.5 t/ha) and N fertilizer (50-75 kg N/ha) may be necessary.

N and Longitude 5 0 13'E, 350m above sea level) to study the effect of cow-dung, nitrogen and weed interference on the elemental sulphur content of onion (Allium cepa L.). The treatments consisted of three levels of cow-dung (0, 15 and 30 t/ha), three levels of nitrogen (0, 50 and 75 kg/ha) and three weeding regimes (weedy check, 4 and 6 weeks after transplanting) laid out in a randomized Complete Block Design (RCBD) with three replications. The elemental sulphur content (mg/g) of the onion bulb, was studied. The result showed significant (P < 0.05) effect of cow-dung, nitrogen and weed interference on the elemental sulphur content of onion. Highest level of sulphur content were obtained with 15 t/ha cow-dung, 75 kg/ha nitrogen and 4 WAT weeding regime. Based on the finding of this study, it could be concluded that for optimum onion production in the Sokoto Rima Fadama, a combination of 15 t/ha cow-dung, 75 kg/ha nitrogen coupled with the 4 WAT weeding regime is the most suitable.

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