In scientific irrigation scheduling water should be applied to a crop
at an appropriate soil water tension to fulfil its evapotranspiration
requirement. Automatic control of water application at predecided soil
water tensions is an effective irrigation scheduling technique. This
can be achieved through an indigenously developed auto irrigation syst
em. In this system soil water tension is sensed through a modified man
ometer type tensiometer. The design provides control of irrigation at
the predecided soil water tensions and preprogrammed timer. The circui
try can be operated with a 12 V d.c. storage battery for a long period
. (C) 1997 Elsevier Science B.V.