Nitrogen use efficiency of extra early maize varieties as affected by split nitrogen application in two agroecologies of Nigeria

Abstract

Poor yield of maize has been attributed to low soil N since maize requires high Nitrogen for optimum productivity. Field experiments were conducted in the late season of 2014 at IITA, Research Farms, in Ibadan and Mokwa. The research was to evaluate the effects of split N fertilizer on nitrogen use efficiency of extra early maize varieties. Arrangement was 5 x 8 factorial fitted into Randomized Complete Block Design, with four replications. Extra early maturing maize varieties (2013 TZEE-W DT STR, TZEE-Y Pop STR C4, TZEE-W Pop STR C5, 2013 TZEE-Y DT STR, and 99 TZEE-Y STR QPM) with Nitrogen fertility rates ( 0 kg N ha-1 (Control), 30 kg N ha-1 single, 60 kg N ha-1 single, 60 kg N ha-1 split (30:30) applied at 2 and 4 weeks after sowing (WAS), 90 kg N ha-1 split 60:30 applied at 2 and 4 WAS, 90 kg N ha-1 split (30:30:30) applied at 2, 4 and 6 WAS, 120 kg N ha-1 split (60:60) applied at 2 and 4 WAS and 120 kg N ha-1 split (30:60:30) applied 2, 4 and 6 WAS). Data collected were subjected to Analysis of Variance procedure and significant means were separated using Duncan’s Multiple Range Test at p<0.05. Results showed that maize variety 2013 TZEE-W DT STR produce highest number of leaves, plant height, leaf area, cob yield (3.33, 3.15 t ha-1), grain yield (2.57, 2.38 t ha-1) and Nitrogen use efficiency (33.03, 28.95%) at Mokwa and Ibadan respectively. Split application of 90 kg N ha-1 as (60:30) at 2 and 4 WAS produce significantly (p<0.05) higher 1000 grain weight, cob yield (3.90, 3.73 t ha-1) and grain yield (2.99, 2.80 t ha-1) at Mokwa and Ibadan respectively. The control produced significantly reduced dried cob and grain yield by (85, 81%) and (84.4, 80.4%) in Mokwa and Ibadan respectively, compared to the best rate of 60:30 split N application. The N application of 30 kg N ha-1 as single dose had the highest Nitrogen use efficiency (51.3, 43.0 %) in both Mokwa and Ibadan, which was significantly different (p<0.05) from the rest treatments. Across the varieties used in both locations, Mokwa agro-ecology zone proved to be a favourable location for higher yield of extra early maize varieties. The study concluded that application of 30kgN/hectare at two weeks after sowing efficiently improved Extra early maize varieties and is thus recommended as low input package for resource poor farmers.