RATE OF NITROGEN APPLICATION INFLUENCES YIELD OF MAIZE AT LOW AND HIGH POPULATION IN KHYBER PAKHTUNKHWA, PAKISTAN

Abstract

Getting maximum production from maize (Zea mays L.) lies not only to economize the N application to crop but also to maintain a desired plants density. Field experiments were conducted as spring and summer season (S) crops for two years at Cereal Crops Research Institute, Nowshera. Three plant populations (PP = 43, 53 and 67) thousands ha-1 and three nitrogen rates (N = 90, 120 and 150 kg ha-1) were studied for grain yield of maize. The experiments were conducted in completely randomized block (RCB) design with split plot arrangements. Treatment PP was assigned to main and N rates to the subplots in three replications. Sowing of spring experiments were done in March and harvested in July while sowing of the summer experiments were done in July and harvested in November. Experimental results revealed that emergence, silking, tesseling and maturity took more days in spring than summer. Plant height (PH) and ear height (EH) were observed higher for the summer. Low PP (43,000) sowed lower PH and EH over the higher PP. Increasing N augmented both PH and EH of maize. High N applied 150 kg ha-1 delayed maturity. Summer over spring season crop showed higher leaf area index (LAI) which did increase by increasing the treatment PP and/or N rates. Interaction of the treatments S x PP, S x N, PP x N and S x PP x N were found significant for the LAI. Grain yield (GY) in summer was higher than spring sown crop. This increase in the GY was observed in coordination with increasing the treatments PP and N. The finding suggests that GY of summer crop was relatively stable. Moreover, growing maize at higher population (67,000 ha-1) treated with nitrogen 150 kg ha-1 is economical for ‘Jalal’ variety in the area as summer crop.