Precision Agriculture Technologies for Nitrogen Fertilizer Management.

With the global population expected to surpass 9 billion people by 2050, sustainable increases in food production will be a necessity. A key contributor to this increase will be the efficient and effective use of nitrogen (N) fertilizer. 4R nutrient stewardship – applying the right nutrient source at the right rate, at the right time, and in the right place – is an innovative approach in fertilizer management. However, while 4R stewardship provides a framework that can result in improvements in nutrient performance, implementation is greatly enhanced by the tools and technologies, associated with precision agriculture (PA). The objective of this presentation is to highlight current PA strategies that have the potential to increase the nutrient use efficiency (NUE) of N fertilizer. Variable rate N (VRN) management using crop canopy sensors is one technology that has resulted in improvements in NUE compared to standard, uniform N rates and other site-specific VRN management tools. Combining crop sensors with soil-based management zones (MZ) can further enhance the efficiency of fertilizer inputs. Other research has demonstrated that mounting crop sensors on a UAV can provide a viable alternative to ground-based sensors while eliminating some of the obstacles to grower adoption of sensor technology. Aerial and satellite-based imagery are also being used make site-specific N fertilizer decisions. Adding to the complexity of N management is the increasing adoption of variable-rate seeding and irrigation. The interaction of these inputs and the resulting effects on N fertilizer will also be discussed. Implementing PA technologies within the context of 4R nutrient stewardship is an efficient and effective way to achieve the goals of N fertilizer management for sustainable agricultural systems.