Ecological Boundaries and Interference with the Global Nitrogen Cycle: A Review on Soil Nitrogen Management Strategies

Purpose : Nitrogen (N) fertilizer is a major input in agro-ecosystems and has health, economic, and environmental implications. Changes in the global N cycle has transgressed the ecological safe boundary at present. Therefore, sustainable soil N management tools should be identified and implemented to reduce environmental implications of agriculture. This review paper intends to describe the magnitude of the global N based pollution, its health, economic, and environmental implications and suggest for approaches to achieve sustainable soil N management. Research Method : This paper shares a literature review on current efforts in optimizing soil N management. The central topic is an on-farm experiment conducted in the University of Nebraska-Lincoln, USA that monitors and manages in-season N in maize using a crop sensor technology. Other reliable findings from previously conducted studies worldwide are presented as well. Findings : Results of field studies revealed that there were no significant variations in maize grain yields between sensor-based treatment and farmer's business-as-usual treatment However, the crop sensorbased treatment recorded savings of N at an average rate of 32 kg/ha. Based on the reported findings in literature, advanced fertilizer technology, manipulation of fertilizer application methods and development of conceptual models to predict the crop N need are other potential tools to optimize N in agriculture. Research Limitation : The behavior of reactive N in soil is unpredictable due to a complex interacting effect of crop, soil, climatic and management factors. Originality/Value : In Sri Lanka as a country having a significant stake in agriculture, understanding and adoption of some of these available new technologies for efficient N management will serve well in our efforts for ecological sustainability.