GROWTH AND YIELD OF ONION (Allium cepa L.) AS INFLUENCED BY STRAIGHT AND COMBINED APPLICATION OF INORGANIC AND ORGANIC SOIL AMENDMENTS IN JEGA, SUDAN SAVANNA, NIGERIA

Field experiments were conducted in Fadama Teaching and Research Farm of the Kebbi State University of Science and Technology Aliero, located at Jega (Lat. 12o 12’ N and Long. 4o 22’ E) in the Sudan savannah agro-ecological zone, during the 2011-2013 dry seasons. The aim was to determine the response of onion (Allium cepa L.) to straight and combined application of inorganic and organic soil amendments. The treatments consisted of six (6) soil amendments, each designed to supply the recommended dosage of 120 kg Nha-1 using a compound fertilizer NPK [15:15:15], farm yard manure and six-month old poultry manure from an automated battery cage system. Results revealed that onion plant height (10 WAT), mean bulb diameter, mean bulb weight and bulb yield (t ha-1) were significantly increased when the recommended nitrogen dose of 120 kgNha-1 was applied using 100% NPK (800 kgNPK [15:15:15/ha]) or a combination of NPK and PM at 50:50 ratio. Based on the results of this study, it was concluded that the integration of organic and inorganic soil amendments in form of NPK compound fertilizer and poultry manure combination at 50:50 ratio could be adopted for higher onion bulb yield, considering the complimentary role of poultry manure in improving the physical quality of the soil.