EFFECTS OF FERTILIZER TYPES ON MAJOR SOIL NUTRIENTS AND PERFORMANCE OF MAIZE (ZEA MAYS L.) IN ADO – EKITI, SOUTHWESTERN NIGERIA

A two – year field experiment was conducted at the Teaching and Research Farm of the University of Ado - Ekiti, Nigeria, during early 2006 and 2007 cropping seasons to appraise the influence of fertilizer types on major soil nutrients and performance of maize (Zea mays L.). The experiment was laid out in a randomized complete block, with three replications. Treatments included: no fertilizer (NF) (control), inorganic fertilizer (IF), organic fertilizer (OF), and inorganic + organic fertilizer (IF + OF). The results obtained indicated that there were significant differences (P ≤ 0.05) among the fertilizer types in growth and yield indices of maize. NF and IF decreased soil organic carbon (SOC) by 74 and 57%, respectively, contrasting increases of 31 and 18% for OF, and IF + OF, respectively. Similarly, NF and IF decreased total nitrogen (N) by 71 and 52%, respectively, compared to increases of 28 and 43% for OF, and IF + OF, respectively. The percentage decreases in available phosphorus (P) were 74 and 66% for NF and IF, respectively, as against increases of 33 and 54% for OF, and IF + OF, respectively. The two – year average values indicated that fertilizer types significantly increased maize leaf area from 0.52 m2/plant for NF to 0.77, 0.67 and 0.92 m2/plant for IF, OF, and IF + OF, respectively. Similarly, fertilizer types significantly increased maize grain yield from 1.93 t ha-1 for NF to 5.89, 5.21 and 6.32 t ha-1 for IF, OF, and IF + OF, respectively.Â