PT  - JOURNAL ARTICLE
AU  - Khosla, R.
AU  - Fleming, K.
AU  - Delgado, J. A.
AU  - Shaver, T. M.
AU  - Westfall, D. G.
TI  - Use of site-specific management zones to improve nitrogen management for precision agriculture
DP  - 2002 Nov 01
TA  - Journal of Soil and Water Conservation
PG  - 513--518
VI  - 57
IP  - 6
4099  - http://www.jswconline.org/content/57/6/513.short
4100  - http://www.jswconline.org/content/57/6/513.full
AB  - 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.