Irrigation Management

 

Principles of irrigation

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.

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 planting may be pre-poned or post-poned 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.

References Kerala Agricultural University.  2011.  Package of Practices Recommendations: Crops.14th edition. Kerala Agricultural University, Thrissur- 360 p.