GROWTH AND MARGINAL BENEFIT OF ONION (<i>Allium cepa</i> L.) PRODUCTION UNDER DIFFERENT RATES OF NITROGEN AND FARM YARD MANURE IN MAIDUGURI SUDAN SAVANNA, NIGERIA

Experiment was conducted during the dry season of 2015 and 2016 at the Teaching and Research Farm of the University of Maiduguri Sudan Savanna Nigeria, to determine the response of onion (Allium cepa L.) to different rates of farmyard manure and nitrogen. Treatments consisted of three levels of farmyard manure (0 t/ha, 15 t/ha and 30 t/ha) and four levels of nitrogen (0 kgN/ha, 50 kgN/ha, 100 kgN/ha and 150 kgN/ha) which were laid out in a Randomised Complete Block Design (RCBD) and replicated three times. The parameters studied include; establishment count, plant height (cm), number of leaves per plant and bulb diameter (cm). Data were analysed using Analysis of Variance and means were separated using DMRT at 5% level of probability. The findings of results in 2015, 2016 and the combined analysis indicates that, there was significant (P<0.05) effect of farmyard manure and nitrogen fertilizer in all the parameters studied throughout the stages of the investigations. Application of farmyard manure at 30 t/ha and nitrogen at 150 kg/ha recorded the highest values, which were followed by 15 t/ha farmyard manure and 100 kg/ha nitrogen in all the parameters investigated. The results further showed that application of different rates of farmyard manure and nitrogen fertilizer had significantly affected marginal benefit of the onion production. The application of farmyard manure and nitrogen at 30 t/ha and 150 kgN/ha respectively gave the highest marginal benefit. Based on the results of the study conducted, a recommendation of 30 t/ha farmyard manure and 150 kg N/ha is made for Onion farmers in Maiduguri, Borno State.