Use of site-specific management zones to improve nitrogen management for precision agriculture

Nitrogen (N) input is one of the most important factors in maximizing yields and economic returns to farmers. Of the essentials nutrients, N is required in large quantities, and it is the most mobile and dynamic nutrient in soil systems. It is well-documented that soil physical and chemical properties are spatially variable and affect N dynamics and the mechanisms for its losses. For example, N dynamics could vary from high denitrification N2 losses from ponded areas with low drainage to high NO3 · leaching losses from coarse-gravelly areas of the field. Recent developments in new technologies are allowing us to identify, measure, and map these changes across the field. We found that N management using site-specific management zones (SSMZ) that account for soil variability and productivity provides the amounts of N needed to increase yields and maximize the agronomic use efficiency of the applied N. The SSMZ-based N application outperformed treatments that used yield-goal-based and uniform N application rates. Grid-based N application treatments performed as well as the SSMZ for yields but were more inefficient as far as the unit of yields produced by unit of N fertilizer applied. The SSMZ can be used to improve N management and use efficiency of the applied N to increase yields and reduce N losses to the environment.