MAIZE RESPONSE TO YIELD AND YIELD TRAITS WITH DIFFERENT NITROGEN AND DENSITY UNDER CLIMATE VARIABILITY

Abstract

To study yield and yield traits of maize, two experiments were conducted in 2006 as spring and summer crops and repeated in 2007. Three plant populations (43, 53, and 67 thousands ha-1) and three nitrogen (N) rates (90, 120 and 150 kg N ha-1) were compared in a completely randomized block design with split plot arrangement. The treatments plant population was assigned to the main and N to sub plots in three replications. Sowing of spring crop was done in March and harvested in July and likewise the summer crop in July and harvested in November. Each experimental unit comprised of 5 × 6 m area having eight rows spaced 0.75 m. Experimental results revealed that grain yield (GY) of summer was higher than spring season. Higher GY was associated with increases in the plant population and nitrogen rate. The treatment plant population of 53,000 and 67,000 ha-1 did not differ. However, each increase in the N rate significantly increased GY. This increase in the GY by increasing N was due to increases in the ear length (EL), ear diameter (ED), grain number (GN) and thousand grain weight (TGW). Increasing plant population of maize did not show any remarkable changes in the yield traits. The study revealed that differences in GY due to seasonal climate cannot be rewarded with increase in either plant population or nitrogen rates. Moreover, spring and summer season maize crops can economically be planted with 150 and 120 kg N ha−1 at 53,000 and 67,000 ha−1 populations, respectively, to save environment and production cost.