• Water is one of the important inputs in crop production. Dry Spells during flowering stage of rainfed maize reduces productivity of Kharif maize.
• Even though the productivity of rabi maize is high, area is less and hence overall average productivity of maize in India is only 1667 Kg/ha compared to world productivity of 3778 Kg/ha.
• Efficient water management is the key to increase the productivity of maize in India.
• Maize is a sensitive crop to moisture.
• Excess moisture in the initial stages is harmful to crop. Hence arrangements must be made to remove excess water upto knee high stage.
• Water stress at flowering and seed formation stages reduces the yield of crop.
• Water stress hastens tasseling (Male Flowers), pollen dehiscence and delays silking (emergence of female flowers). Result is barrenness due to failure of pollination.
• Water stress at flowering reduces yield of crop by 40 to 80 percent. Therefore in the initial stages upto rank vegetative growth, irrigations should be scheduled at longer intervals where as during flowering at shorter intervals.

• Maize is quick, vigorous and tall growing crop having broad leaves , therefore its water requirement is exceptionally high.
• A vigorous growing maize plant requires about 2-3 litres of water per day during peak growing period or an average consumptive use of water varies from 2.5 to 4.3 mm/day.
• The crop cannot tolerate Excess water or waterlogging conditions. Crop under water logged conditions become pale, grow poorly and the uniformity of the crop is lost.
• Waterlogging in maize field for one-day damages the crop stand for three days it almost spoils the whole crop. So efficient drainage is of greater significance than Irrigation.

• Climatic conditions
• Soil type
• Type of the variety of crop grown
• Organic matter content of soil
• Growth stage of crop

• There are certain critical growth stages of maize for irrigation in new plant types at which moisture stress results in considerable reduction of grain yield. The most pronounced critical stages for irrigation are
• Seedling stage
• Knee- height stage
• Tasseling stage
• Silking stage
• Grain filling stage
• Of these moisture stress at early growth stages results in a delayed tasseling and silking by 3-5 and 5-8 days respectively, while stress at later stages results in drastic reduction in yield.

• Water requirement of Kharif maize is 400-550 mm while that of Rabi maize is 450-600 mm.
• Even though maize roots can penetrate upto 120 cm., the density of roots is high only at 60 cm.
• After every crop of maize, ploughing with diskplough and working sub soil after every three years, raising of green manure crops like Sunhemp and their incorporation into soils make the soils loose and friable upto 120 cm.
• Hence roots of subsequent maize crop penetrate to deeper layers and efficiently use water. Presowing irrigation to Field capacity is very important as Maize seed will not germinate unless it absorbs moisture to double its weight.
• First irrigation should be given upto 120 Cm, depth. Second irrigation after 10 to 15 days depending upon soil, temperature and wind velocity. Schedule irrigations at more frequent intervals in dry weather and less frequent intervals in humid weather.
• Scheduling of irrigations in maize depletion of 50 percent available soil moisture from field capacity is benefited.

Irrigation schedule for kharif maize

• The crop is grown rainfed during kharif season where the distribution of rainfall is enough to ensure adequate soil moisture during the life cycle of the crop.
• For constructing high & stable yields, the available sources of irrigation should be tapped to provide 1 or 2 irrigation at the critical stages in any dry spell period.
• Maize is known to be susceptible to water logging as well as soil moisture stress.
• Sowings made on ridge is with the provision of surface drainage can overcome the constraints of waterlogging in uplands.
• Maize is susceptible to moisture stress throughout its life cycle. Since flowering and grain-filling stages are most critical, the crop should be irrigated at these stages, if rains fail.

Irrigation schedule for rabi maize

• The rainfall during Rabi is rather inadequate for successful cultivation of high-yielding maize hybrids.
• Timely availability of assured irrigation is one of the major factors determining the success to crop.
• Where soils are generally light, it is desirable to schedule the irrigations at 70% soil-moisture availability throughout the period of crop growth and development.
• In heavy soils, a moisture level of 30% during the vegetative stage and 70% during the reproductive and grain-filling period is desirable for obtaining optimum yield.
• Four to six irrigations are needed during the Rabi crop season. If six irrigations are given, they should be applied at the following crop growth stages
  1. Two irrigations up to flowering at an interval of 20-25 days
  2. One (essential) at the time of flowering
  3. Two after flowering
  4. One at the early grain-filling stage.
• If only five irrigations are given, one irrigation at the vegetative stage may be avoided and if only four irrigations are given, irrigation after the dough stage may be avoided. The irrigation schedule may, however be charged suitably if adequate rains are received.