Nitrogen stimulates phenological traits, growth and growing degree days of maize

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; 1/3^rd N at V2, 1/3^rd N at V16 and 1/3^rd 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 (1/3^rd N at V2 stage, 1/3^rd N at V16 stage and 1/3^rd 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.