From Agronomists of the
Potash & Phosphate Institute
655 Engineering Drive, Suite 110
Norcross, Georgia 30092-2837
Phone (770) 447-0335

Winter 2001, No. 8


Fertilization by management zones provides an opportunity to better fit soil characteristics interacting with crop nutrition with site-specific crop need for fertilizer nutrients. Management zones seem to work best when an abundance of information is available that characterizes the field and where there is significant crop yield variability within the field.

Delineation of each management zone in a field is key to proper analysis of a field and for best determination of crop nutrient needs. These zones begin to take shape with the overlay of basic data sheets associated with soil type, cation exchange capacity, previous crop yield, previous soil analysis data, organic matter, topography, and other such information. Also, a given zone is often resized as new information becomes available that better defines the land’s potential to produce.

With time and experience, management zones can be defined for different variable rate inputs such as lime, nitrogen, phosphorus, and potassium. Other variable rate inputs include seed, crop protection products, irrigation water, etc.

Crop and soil management specialists suggest the following guidelines as management zones are developed for improved fertilizer use effectiveness, crop yield improvement, and profitability.


For more information, contact Dr. Noble R. Usherwood, Southeast Director, PPI, 233 Kenilworth Circle, Stone Mountain, GA 30083. Phone: (404) 294-0137. E-mail:
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