RESPONSE OF SAMAZ-14 -14 MAIZE (Zea mays L.) TO NITROGEN FERTILIZER RATES IN YOLA, NORTHEASTERN NIGERIA
A field experiment was conducted at Lake Gerio, Jimeta–Yola, Adamawa State, Nigeria, to determine the response of SAMAZ-14 maize to nitrogen fertilizer. Nitrogen was evaluated at 0, 30, 60, 90 and 120 kg N ha−1 within a nitrogen × zinc factorial experiment arranged in a randomized complete block design with three replications. This paper reports the nitrogen main effects for the Yola site. Nitrogen significantly influenced late-season plant height, dry-matter production and major yield attributes. The tallest plants at 75 days after planting (103.14 cm) occurred at 120 kg N ha−1, whereas 60 kg N ha−1 produced the greatest grain number per cob (458.67), 100-seed weight (28.65 g), grain weight per cob (138.33 g) and reported grain-yield value (67.33 in the source table). Relative to the unfertilized control, these responses represented increases of approximately 21.3, 23.7, 15.0 and 22.0%, respectively. The response declined above 60 kg N ha−1 for most yield variables, indicating that maximum vegetative growth did not coincide with maximum reproductive performance. Nitrogen × zinc interactions were significant for 100-seed weight and grain yield; consequently, the 60 kg N ha−1 rate should be regarded as a provisional Yola recommendation until the treatment-combination means, yield units and economic returns are verified.
Keywords: nitrogen fertilizer; maize; SAMAZ-14; grain yield; Sudan savanna; Yola
