LEVEL and low-gradient border
checks for irrigating field crops are
used where irrigation water is limited,
where periodic leaching of salts is required,
and where maximum use of
rainfall is desired. Level basin irrigation
has been used for centuries, especially
for rice irrigation. In northern
Italy where rice is one crop in the rotation,
level basins are used for irrigation
of other farm crops. These systems
briefly described by Mead (5) * are
still in use today. Petrov (7) described
similar systems on natural slopes in the
Golodnaya Steppe where land slopes
range from 0.05 to 0.25 percent
