A review of the determination of nitrogen fertilizer levels for maize in different ethiopian agro-ecologies

Fertilizers need to be used judiciously to avoid negative, undesirable impacts on ecology and ensure the sustainability of agricultural production systems. Accordingly, site-specific nutrient management approaches aim to achieve efficient fertilizer use, which increases profitability for farmers and results in high production per unit of area applied. Hence, the objective of this review was to investigate the determination of optimum nitrogen fertilizer rates for maize production in different agro-ecologies in Ethiopia. As several research findings have shown, the application of different nitrogen fertilizers significantly affects various aspects of growth, yield, and yield components of maize crops. Based on this, the review showed that growth, yield, and yield parameters of maize crops increased with increasing rates of nitrogen fertilizer. The review showed that the highest growth, yield, and yield-related parameters of maize in Ethiopia's different agro-ecologies were obtained from 65 kg/ha to 138 kg/ha of nitrogen fertilizer. As found in this review, the response of the maize crop to nitrogen fertilizer gives a different reflection at a different location. It was concluded that nitrogen fertilizer recommendations should be given to site-specific locations. Therefore, rather than simply recommend a single rate of nitrogen fertilizer to different agro-ecology and soil types of the country, it is necessary to conduct soil test-based, plant tissue analysis, and the response of maize crops to nitrogen fertilizer correlated with site-specific locations are recommended to determine nitrogen fertilizer to attain optimum production and sustainable production of maize crops.