Evaluating the Impact of Nitrogen Application on Growth and Productivity of Maize Under Control Conditions

Climatic conditions significantly affect the maize productivity. Among abiotic factors, nitrogen (N) fertilizer and temperature are the two important factors which dominantly affect the maize (Zea mays L.) production during the early crop growth stages. Two experiments were conducted to determine the impact of N fertilizer and temperature on the maize growth and yield. In the first experiment, the maize hybrids were screened for their sensitivity to temperature variations. The screening was based on the growth performance of the hybrids under three temperatures (T ₁ = ambient open-air temperature, T ₂ = 1°C higher than the ambient temperature, and T ₃ = 1°C lower than the ambient temperature) range. The results showed that an increase in temperature was resulted less 50% emergence and mean emergence (4.1 and 6.3 days, respectively), while emergence energy and full emergence were higher (25.4 and 75.2%, respectively) under the higher temperature exposure. The results showed that Syngenta 7720 and Muqabla S 25W87 were temperature tolerant and sensitive maize hybrids, respectively. The second experiment was carried out to study the response of the two selected maize hybrids (Syngenta 7720 and Muqabla S 25W87) to four N fertilizer applications. The results revealed that the maximum N use efficiency (19.5 kg kg^-1) was achieved in maize hybrids with low N application (75 kg N ha^-1 equivalent to 1.13 g N plant^-1). However, the maximum maize grain yield (86.4 g plant^-1), dry weight (203 g plant^-1), and grain protein content (15.0%) were observed in maize hybrids that were grown with the application of 300 kg N ha^-1 (equivalent to 4.52 g N plant^-1). Therefore, it is recommended that the application of 300 kg N ha^-1 to temperature tolerant maize hybrid may be considered best agricultural management practices for obtaining optimum maize grain yield under present changing climate.