Abstract
Field experiments were conducted during 2009 and 2010 to evaluate the effects of nitrogen (N) application timings and rates
on phenology of autumn sown maize under semi-arid climatic conditions of Faisalabad, Pakistan. Plant development, growth
and yield components were optimized by the N application in three splits; 1/3rd N at V2, 1/3rd N at V16 and 1/3rd N at R1
stages at the rate of 250 kg ha-1. At this rate, the crop achieved more calendar days and thermal time in each growth stage.
The treatments T2 (1/3rd N at V2 stage, 1/3rd N at V16 stage and 1/3rd N at R1 stage) and N4 (250 kg N ha-1) accumulated the
maximum days to silking and maturity (51 and 102 days, respectively), which resulted in the maximum crop growth rate and
grain yield (8.38 t ha-1). The highest net benefit and marginal rate of return ($1857 and 22%, respectively) were achieved by
N4 treatment. Therefore, 250 kg N ha-1 with three above mentioned splits of N application may produce optimum grain yield
of maize under semi-arid environmental and agricultural conditions similar to those of the reported experiments.
