FROM the air, the Flint river basin in south-western Georgia
looks monotonous. Appearances, however, deceive. What seems a
Euclidian plane as well as a geographical plain is actually a
landscape of low hills, shallow valleys, stream beds, drainage
ditches and river banks. Nor is the soil the same everywhere.
Some is sandy; some is rich in clay; some is a mixture of the
two. All of these details matter, if you are a farmer—which many
of its residents are.  From the air, too, something else is
apparent: a strange tendency for the basin's crops to grow in
circular patches. This is caused by the way they are watered—for
the predominant system employs sprinkler heads attached to hoses
that dangle from wheeled trusses which move in a circular
pattern around a central tower. The whole arrangement is
portable, and can thus be transported from field to field in
order to water a whole farm.  Centre-pivot irrigation, as this
system is known, is reasonably effective. But it is a one-size-
fits-all approach to distributing