EFFECT OF PLANT POPULATION AND NITROGEN LEVELS AND METHODS OF APPLICATION ON EAR CHARACTERS AND YIELD OF MAIZE

Abstract

Field experiments were conducted at Agricultural Research Farm, NWFP Agricultural University, Peshawar, Pakistan during summer 2006 and 2007 in randomized complete block design with split plot arrangements having three replications. Four plant populations (4.5, 6, 7.5 and 9 plants m -2 ), three nitrogen levels (80, 120 and 160 kg ha -1 ) and three nitrogen application methods (full dose at emergence, half each at emergence and knee height, one third each at emergence, knee height and pre-tasseling stages) were included in the experiments. Plant populations (PP) were kept in the main plot, while combinations of nitrogen levels (N) and nitrogen application methods were kept in the sub-plots. Maize variety Azam was sown with the help of a planter in a plot size of 3 x 3 m 2 with row to row distance of 75 cm. Grain and biological yields increased with increase in PP from 4.5 plants m -2 to 7.5 plants m -2 but further increase in PP did not significantly enhance grain and biological yields of maize. Likewise, increase in N level significantly improved grain and biological yields of maize up to 120 kg ha -1 . Similarly, N application in three splits performed better than sole or two splits in terms of biological yield production in maize. HI consistently increased with increase in PP from 4.5 plants m -2 to 9 plants m -2 . Ear characters were not affected by PP except grain weight which was higher at PP of 7.5 plants m -2 . In similar fashion, N level significantly affected only grains row -1 and grain ear -1 . Both grains row -1 and grain ear -1 increased with increase in N level from 80 to 160 kg ha -1 but the N level of 120 and 160 kg ha -1 were statistically at par with each other. It is concluded that higher yield and better ear characters were obtained at PP of 7.5 plant m -2 with N application @120 kg ha -1 .