Improved Nitrogen Use Efficiency in Lowland Rice Fields for Food Security

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The increasing global population and changing food consumption patterns necessitate a substantial improvement in agricultural productivity to ensure food security without further encroachment on wilderness areas. This publication highlights the significance of rice as a staple food for over half of the world's population, particularly in Asia, where a large portion of the global poor resides. Given the limited availability of arable land, the demand for rice is expected to rise significantly by 2030. Consequently, enhancing rice productivity becomes crucial to meet the growing population's food requirements. This necessitates the judicious utilization of agricultural inputs, including quality seeds, fertilizers, water management, and other good agricultural practices. Nitrogen (N) fertilizer, especially urea, plays a pivotal role in achieving high rice yields under irrigated and favorable rain-fed conditions. However, research indicates that more than 50% of applied nitrogen is not utilized by crops, leading to environmental issues such as greenhouse gas emissions, eutrophication, and groundwater pollution. Moreover, nitrogen fertilizers constitute a considerable proportion of crop production costs. Therefore, adopting fertilizer management techniques that promote increased use efficiency, crop yield, soil health, and profitability while minimizing environmental impact is imperative. One such technique gaining traction is urea deep placement (UDP), wherein urea is transformed into briquettes and placed at a specific depth within the soil. This publication explores the potential of UDP in improving nitrogen retention and reducing losses. Studies conducted across countries have demonstrated the efficacy of UDP in increasing grain yields, farm profits, and nitrogen use efficiency, while mitigating negative environmental effects. By reducing urea use by over 30% and increasing yields by an average of 15-20%, UDP has proven to be a sustainable solution for rice farmers. The technology has been successfully implemented in Bangladesh, with significant economic savings for the government in terms of fertilizer subsidies. Scaling up UDP to larger rice-growing regions in Asia holds substantial potential, particularly where nitrogen fertilizer subsidies exist. Additionally, the publication emphasizes the importance of selecting appropriate placement methods, such as UDP, to improve nitrogen use efficiency. UDP reduces nitrogen losses through ammonia volatilization and surface runoff, particularly in continuously flooded rice soils. By optimizing nitrogen availability to crops throughout the growth stages, UDP significantly reduces losses to the atmosphere, groundwater, and waterways. Compared to traditional broadcast application, UDP can increase nitrogen use efficiency up to 80%. Furthermore, UDP exhibits promise in stress-prone environments, such as drought, submergence, and salinity. Unlike conventional split nitrogen application, which relies on weather conditions, UDP offers farmers greater control over fertilizer application, enhancing their resilience to unpredictable climatic events. Finally, the publication emphasizes the importance of balanced fertilizer use, including nitrogen, phosphorus, potassium, and other secondary and micronutrients, to achieve sustainable and productive agricultural systems. Ensuring that farmers in developing countries have access to knowledge and resources for balanced fertilization is crucial for maximizing crop yields and food security.
Deep placement, Nitrogen-use efficiency, Food security, Technology
Gaihre, Y.K., U. Singh, I. Jahan, and G. Hunter. 2017. “Improved Nitrogen Use Efficiency in Lowland Rice Fields for Food Security,” Fertilizer Focus, 48:51.