Effect of Nitrogen Fertilization Levels on Two Maize Varieties under Green Mountain Conditions

Abstract

This study was conducted during the 2025 growing season at the Crop Production Farm, Faculty of Agriculture, Omar Al-Mukhtar University, Al-Bayda, to evaluate the effect of different nitrogen fertilizer levels on two maize (Zea mays L.) cultivars under the environmental conditions of Al-Jabal Al-Akhdar. The experiment was arranged in a split-plot design, with cultivars assigned to main plots and nitrogen fertilizer levels to subplots. Three nitrogen treatments were applied: a control without nitrogen fertilization and two levels of urea fertilizer. Analysis of variance showed no significant differences between the two cultivars for most ear and grain traits, and nitrogen levels had no significant effect on the structural ear characteristics. However, nitrogen fertilization significantly affected several yield-related traits, including number of kernel rows, kernel weight per row, and total kernel weight per ear. A highly significant interaction between cultivar and nitrogen level was observed for cob weight and total kernel weight. Mean comparisons indicated that the first nitrogen level produced the highest values for most yield traits, whereas the lowest values were recorded at the third level, highlighting the importance of balanced nitrogen application for optimal growth and yield. The study recommends adopting an appropriate nitrogen fertilization level under Al-Jabal Al-Akhdar conditions, taking cultivar differences into account, to improve maize productivity and nitrogen use efficiency.