Influence of varying nitrogen levels on growth, yield and nitrogen use efficiency of hybrid maize (Zea mays)

Present investigation was carried out at Natore Sugar Mills area, Natore, Bangladesh during 2014-15 to evaluate the growth and yield responses of hybrid maize varieties under different levels of nitrogen fertilization.Two hybrid maize varieties viz.BARI hybrid maize-7 and BARI hybrid maize-9 were tested under four nitrogen levels (N0= without external nitrogen supply, N1= 115 kg N ha -1 , N2= 230 kg N ha -1 , and N3= 345 kg N ha -1 ).All recommendations agronomic practices were used for both the variety.Yield and yield traits (plant height, plant girth, total leaves plant -1 , effective leaves plant -1 , noneffective leaves plant -1 , total root plant -1 ,straw weight plant -1 ,cob length, grain free cob, cob girth, grain line cob -1 , total grain cob -1 , grain number line -1 ,1000-grains weight, grain weight cob -1 ,grain yield, straw yield and biological yield) were measured during and on the completion of the study.BARI hybrid maize-9 achieved maximum yield (10.99 t ha -1 ) and it was followed by the BARI hybrid maize-7 (10.37 t ha -1 ).Results of study revealed that yield traits and final yield significantly increased with increasing nitrogen fertilizer from 0 to 345 kg ha -1 .Among various tested N-fertilizer doses, highest grain yield was obtained from the plot treated with N3 treatment (345 kg ha -1 ) but it was not statistically differing from the N2 treatment (230 kg ha -1 ).Therefore, N2 treatment (230 kg ha -1 ) could be recommended for variety BARI hybrid maize-9 as the best economical nitrogen level for maximum economical yield of maize.