What Precision Farming Is  (and isn’t)
Site-Specific Management recognizes the variability within a field
and is about doing the right thing, in the right way, at the right
place and time.
It involves assessing and reacting to field variability by tailoring
management actions, such as fertilization levels, seeding rates and variety
selection, to match changing field conditions. It assumes that managing
field variability leads to both cost savings and production increases, as well
as improved stewardship and environmental benefits.
(Berry)