Evaluation of the Relationship between Nitrogen Fertilization and Agronomic Performance of Maize (Zea mays L.) Varieties

The significance of nitrogen fertilizer in maize (Zea mays L.) cultivation cannot be underestimated. Therefore the aim of the study is to assess the responsiveness of maize varieties to four rates of nitrogen fertilization in the formation of grain yield and other agronomic traits. The study area was at the Teaching and Research Farm of Ladoke Akintola University of Technology, Ogbomoso, Nigeria. The test period was between 2021 and 2022 where six varieties of maize (sub-plot factor) were included in an experiment with four rates (0, 30, 90 and 150 kg N/ha) of nitrogen fertilizer (main plot factor) laid down in a randomized complete block design with six replicates. Analysis of variance indicated that there were significant (P < 0.01) differences among maize varieties, nitrogen fertilizer rates, variety × year interaction as well as between the years of evaluation for grain yield and other agronomic traits. Growth parameters and grain yields differed significantly (P < 0.05) between varieties at all nitrogen fertilizer rates. SC 719 produced the highest yield (2512.03 kg/ha), whereas the lowest yield (1721.41 kg/ha) was found in SAMMAZ 27. The shortest anthesis-silking interval (2.4 days), lowest ear aspect score (4.9), highest grain yield (2734.6 kg/ha), plant (167.3 cm) and ear (72.3 cm) heights was recorded from plots fertilized with 150 kg N/ha. All the maize varieties performed better than the widely grown adapted local check (Oba super 6) under 0 kg N/ha. The application of nitrogen fertilizer improves yield and other agronomic traits of the maize varieties. Treatment of 90 kg N/ha gave comparable performance with 150 kg N/ha for most traits. Moreover, judicious nitrogen fertilizer management could ensure high grain yield production and profit.