Scheduling irrigation
Application of irrigation water with respect to time
and space based on the evaporative demand of the crops is referred as
scheduling of irrigation. In water-scarce areas,
irrigation scheduling in rice is
done using saturated soil culture (SSC), alternate wetting and drying (AWD),
tensiometer based irrigation, and critical stage based lifesaving irrigation.
Rice has five critical stages (tillering, panicle initiation, booting,
heading, and flowering/ anthesis). Moisture stress at active tillering phase
and reproductive phase reduces yield by 30% and 50-60%, respectively.
Application of water in AWD or SSC upto tillering followed by maintenance of
5-8 cm standing water saves about 50% of water as compared to continuous
submergence without any yield loss. During kharif, the application of water could be delayed up to 3 days of complete
disappearance of ponded water (5-7 irrigations), while in rabi, the application of water could be delayed up to 1 day of
complete disappearance of ponded water (13-15 irrigations). This method saves
about 9-27% of irrigation water.