Maintain water level at about 1.5 cm during transplanting. Thereafter increase it
gradually to about 5 cm until maximum tillering stage. Drain water 13 days before
harvest.
[Note: In areas where water for irrigation is assured and where acidity is high,
draining and reflooding every 15 days are recommended. In flood prone areas, aged
seedlings of Mahsuri or other varieties recommended for waterlogged conditions may
be planted. The date of planting may be adjusted to avoid synchronization of the
critical stages of maximum tillering or heading with the usual flood period in the
tract.]
During the mundakan crop season, water level of 5 cm need not be maintained
continuously after the cessation of northeast monsoon. Five centimetre irrigation
once in 6 days will be quite adequate for project areas where water is assured.
For summer rice (in situation where the ground water level is shallow, i.e., within
1 m from the surface), 5 cm irrigation two days after disappearance of ponded water
is sufficient instead of 5 cm continuous submergence throughout the crop period.
Irrigation schedule for rice under limited water resources
For summer rice under limited resources of water, phasic stress irrigation can be
practiced to the advantage of saving substantial quantity of irrigation water without
any significant reduction in yield. About 20-30% more area can be irrigated with
the same water resources by adopting any of the following phasic stress irrigation
schedules (given in table). Depending up on the schedule, water saving ranges from
24-36% of the requirement for 5 cm continuous submergence throughout the crop growth.
Grain yield reduction in the above practice is only 0.1% to 1.6%.
Categories of irrigation schedule for rice
Schedule
|
Stages
|
Rooting to max.
tillering
|
Max. tillering to
heading
|
Heading to maturity
|
Category I
|
Continuous submergence
|
Saturation point*
|
Saturation point*
|
Category II
|
Saturation point*
|
Continuous submergence
|
Continuous submergence
|
Category III
|
Continuous submergence
|
Continuous submergence
|
Hair cracking of surface*
|
Category IV
|
Hair cracking of surface*
|
Continuous submergence
|
Hair cracking of surface*
|
*Irrigation at 5 cm to be given at the stages marked.
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