Review on Improving Nitrogen Use Efficiency for Cereal Crop Production

Nitrogen (N) is an essential macronutrient and a major structural and physiological component of basically all processes related to plant development, growth and reproduction. For sustainable agriculture and food production, N is indispensable and it therefore has to be re-supplied to agricultural soils to prevent nutrient depletion and soil degradation. Nitrogen is the most critical externally added input for any crop production system. The half of the global population directly or indirectly depends on nitrogenous fertilizers for food supply. Efficient use of nitrogen is essential to decrease negative impacts of agriculture on the environment. Improvement in nitrogen use efficiency (NUE) is important to reduce input costs and the negative impact of excessive N on the environment. Therefore, response to applied nitrogen and its use efficiency have to be monitored properly for obtaining the maximum potential and sustainable yield. Efficiency of applied nitrogenous fertilizers is very low due to its various losses i.e. volatilization, leaching, surface runoff and denitrification from soil-plant system. Therefore, the proper understanding of advanced soil and plant management practices which helps in enhancement of nitrogen recovery efficiency is one of the key factors to enhance crop output, decreasing cost of cultivation, and to maintain environmental quality which ultimately adds towards the goal of achieving long term sustainable production system. In this review, an attempt has been made summarize the locally as well as scientific soil and crop management technologies used for improving use efficiency of applied N. This paper also discusses nitrogen cycling in soil-plant systems, various N losses pathways, present status and most possible management options at the farm level for enhancing nitrogen use in crop production system. Therefore, use of efficient rates of nitrogen fertilizer application is important with regard to increasing crop productivity and maintaining environmental sustainability.