Performance of maize (Zea mays) cultivars as influenced by grade and application rate of Organo-mineral fertiliser in a transitory rain forest

Field trials were conducted in a transitory humid rain forest, Abeokuta, Nigeria (Latitudes 7？ 15？N, 3？ 25？E, altitude 144 above sea level) in early wet cropping seasons of 2014 (site A) and 2015 (site B). The trials were aimed at investigating the effects of application rates of grades of organo-mineral fertiliser on maize (Zea mays)cultivars. The trials were in split-split plot arrangement fitted into randomised complete block design and replicated three times. In the main plot was variety {Oba super 2 (hybrid) and Suwan 1[open pollinated variety (OPV)]}, sub-plot consisted of grade of organo-mineral fertiliser (A, B, C), while the sub-sub plot was made of application rate (0, 2.5 and 5.0 t ha-1). Oba super 2 had significantly (P< 0.05) more assimilatory surface, with more 100 grain (7.13 g) and ear weight (0.08 kg), harvest index (37.60 %) than OPV maize cultivar (Suwan 1) in 2015. Maize cultivars sown with grade B organo-mineral fertiliser had delayed tasselling (57.50 days) and silking (66.33 days) compared to when sown with other organo-mineral grades. Increasing application rates of organo-mineral fertiliser resulted in increased assimilatory surface and a higher grain yield and its attributes in both years.