Efficient Use of Nitrogen Fertilizers: A Basic Necessity for Food and Environmental Security

Abstract

Use of Fertilizer Nitrogen (N) to increase food production constituted one of the major factors in supporting population growth in the twentieth century. The trend continues in the twenty-first century, particularly in the developing countries of the world. Because a part of the N applied as fertilizer is prone to be lost from the soil-plant system to the environment and degrade its quality, increasing fertilizer N Use Efficiency (NUE) in agricultural farms can lead to achieving both food and environmental security. However, it is a challenging task because NUE is determined by a host of factors including nature of the crops grown, soil quality, and management of fertilizer N and other farm operations. In developing countries like India, China, and Egypt, NUE is rapidly falling since the Green Revolution era because consistently increasing fertilizer N consumption is accompanied by declining crop yield response to applied N. While in countries like the USA, crop yields continued to increase moderately even with a trend in the reduced increase in fertilizer N inputs, in most of the western European countries crop yields continued to improve without further increase or even decrease in fertilizer N consumption since the 1980s. These trends in crop yield and fertilizer N consumption in several developed countries have resulted in a regular increase in NUE for more than the last four decades. In line with the observed trends in NUE in countries like India and China, high N surpluses in agricultural soils are posing a threat to the environment. New knowledge-based N management strategies to improve NUE are becoming available, but significant new investments and partnerships between farmers, scientists, economists, citizens, and industries will be needed to improve NUE in current and future agricultural systems by the widespread adoption of both the existing and emerging technologies.