Plant Density and Nitrogen Effects on Maize Phenology and Grain Yield

Nitrogen (N) and plant density are considered some of the most important factors affecting crop phenology (days to tasseling, silking, and maturity), morphology (leaves plant-1, seeds ear-1, ears 100 plants-1) and grain yield. The effects of plant density and N on phenology, morphology, and yield of maize (Zea mays L.) at Peshawar in northwestern Pakistan were evaluated during 2002 to 2004. The 2 3 6 factorial experiment was designed having two plant densities (60,000 and 100,000 plants ha-1) and three N levels (60, 120, and 180 kg N ha-1) applied to main plots, while six split application of N in different proportions were applied to subplots in two equal, three equal, three unequal, four equal, five equal and five unequal splits at sowing and with 1st, 2nd, 3rd, and 4th irrigation at two week intervals. All the phenological characteristics were significantly affected by year, plant density, rate and timing of nitrogen application. Year and plant density had no significant effect while rates and split application of N had significant effects on the leaf number plant-1 and seed number ear-1. Year, plant density and N rate had significant effects while N splits had no significant effects on the number of ears 100 plants-1 of maize. Significantly higher grain yield was observed under high plant densities, high N rate and split application of N, while its response to year effects was statistically non-significant. Tasseling, silking and physiological maturity were delayed and maximum grain yield was obtained from those plots maintained at higher plant density. Delaying in the phenological characteristics while increasing the number of leaves and seeds plant-1, and number of ears 100 plant-1 through high rate and split application of N results in maximum yield of maize at Peshawar. This study suggested that maize production can be maximized through high plant density and high N split application.