First, we have basin irrigation. Water flows through a canal and basins (10'x3'x4") are opened, flooded in turn.
Second, we have furrow irrigation, in which we flood troughs between ridges. Potatoes are easily grown with this method.
(the blue pipe in the upper left of the above photo carries water down to a demo of two other methods of irrigation: sprinkler and drip. These methods are more costly to set up and maintain but are more efficient. Many farmers prefer these methods because they use less energy to apply water to crops. Pictures to come.)
A few more pictures:
Full tank:
Maize in basin irrigation (still growing on residual moisture):
