Rainfed rice - IRRI books - International Rice Research Institute

Open wells with large diameters
located in the midland region, which
has 37 open wells charged with
seepage water and water from
adjacent fields.
Deepening of existing ponds to hold
additional water.
In situ water conservation
Runoff collectors across the
slope in uplands
The runoff collectors check the loss
of surface rainwater. The water that
collects in the interceptors moves
laterally and serves to charge the
root zones. This keeps the soil wet,
thus facilitating the' growth of good
rice crops. The effects of runoff
collectors on rice yields are given in
the table.
Water Saving, Recycling and Sequential Use Technologies: A Case Study
Pond water available after deepening
Before After
Pond area (ha) 0.25-1.30 0.25-1.30
Depth (m) 0.50-0.70 1.00-1.30
Duration (mo) 4-7 (Jul-Jan) 6-11 (Jul-May)
Volume (ha m) 0.12-0.91 0.25-1.69
Locations of Grain Straw Total
runoff interceptors yield yield /m 2
(t/ha) (t/ha)
Upper slope 1.87 2.94 36049
Middle slope 1.98 3.03 36668
Lower slope 2.00 2.63 43550
Lowest slope 2.22 3.14 44370
Without interception 1.43 2.39 30827
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