Response of Maize (Zea Mays L.) to Plant Population Density and Nitrogen Fertilizer Levels

An experiment was conducted at Agricultural Research Station, Faculty of Agriculture (Saba- Basha), Alexandria University, Egypt, during 2017 summer season to study response of single cross 10 (S.C. 10) to four plant population densities (19000, 23000, 27000 and 30000 plants/ fed) as main plot factor and four nitrogen fertilizer levels (100, 120, 140 and 160 kg/ fed) as sub-plot factor using split-plot design in three replications. The lowest plant density (19000 plants/ fed.) produced the shortest plants (216.38 cm), lowest ear height (139.42 cm), lowest leaf area index (4.36), earliest 50% silking (64.11 days), lowest barren stalks (2.17%) and lowest grain yield/ fed. (3.769 ton).Conversely, it produced the highest number of ears/ plant (1.22), tallest ears (26.62 cm), thickest ears (4.54 cm), highest number of kernels/ row (48.74), heaviest 100-kernel weight (43.29 g) and highest grain yield/ plant (200.09 g). However, the highest nitrogen fertilizer level (160 kg/ fed) produced the highest values for all the studied traits, except barren stalks percentage, where it reached the lowest level (4.04%). Sowing maize at 30000 plants/ fed under 140 or 160 kgN/ fed/., produced the highest leaf area index values (9.11 and 9.47), respectively, while 100 kgN/ fed., application gave the highest barren stalks (14.73%). The lowest plant density (19000 plants/ fed) treated with 160 kgN/ fed produced the highest number of ears/ plant, kernels/ row and grain yield/ plant (1.58, 56.92 and 225.19 g), respectively. The highest grain yield/ fed (4.673, 4.811 and 4.841 t/ fed) resulted from sowing 23000 plants/ fed fertilized with 140 or 160 kgN/ fed and 27000 plants/ fed under 160 kgN/ fed application, respectively.