Irrigation in wheat crop:

Irrigation in wheat crop:
Adequate soil moisture is required for normal development of the wheat plant at all the stage of growth. The crown root initiation stage and heading stage are critical stages when plant suffers most due to moisture stress. The following schedule of irrigation should be followed by dwarf variety of wheat. In case of dwarf yielding variety as pre, sowing irrigation should be given and crop sown when the field become fit for the operation.

First Irrigation: The first irrigation to be standing crop could be given 20-25 days after sowing, i.e. at the crown root initiation stage. In cooler regions like hilly tracts and in late sown wheat, it is desirable to apply first irrigation approximately25-30 days after sowing. Delay   in giving this irrigation should be avoided as it result in upsetting the synchronous tillering in these varieties, subnormal heads, poor root system and finally poor grain yield. It is most critical irrigation.

Second Irrigation: At tillering stage, 40-45 days after sowing.

Third Irrigation: At late jointing stage within 70-75 days after sowing.

Fourth Irrigation: At flowering stage, within 90-95 days after sowing. Irrigation at this stage is also important because during this period plant suffer most from soil moisture deficiency. The grain number and grain size are reduced considerably.

Fifth Irrigation: At dough stage, within 110-115 days after sowing. The total number of irrigations required will vary depending upon soil type, winter rainfall amount of water applied per irrigation.

Under limited supply of water the following irrigation schedule of irrigations should be for the best adopted utilization for available quantity of water.

Where only one irrigation was possible. Give it crown root initiation CRI stage 20-25 days after sowing.
Where two irrigation are available, first irrigation should be given at CRI stage and second flowering stage.
Where three irrigation are possible, first irrigation should be given at CRI stage second at late jointing (boot) stage and third at milk stage. These recommendations strongly stress the importance of irrigation at CRI stage. It has been  found that each week delay in first irrigation from CRI stage results in yield reduction of 2-3 quintal per hectare.

Source: http://agropedia.iitk.ac.in/content/irrigation-wheat-crop