Potato

Water Management

  • Water requirement of potato is supposed to be very high (500-600 mm) but scheduling irrigation at optimum moisture level during critical stages and sub-optimum level during rest of the period may result into about 30 per cent saving in water requirement of the crop.
  • The critical stages have been regarded to be (i) germination, (ii) tuber initiation (iii) early tuber enlargement and (iv) late tuber enlargement.

  • It is recommended to irrigate the crop at a soil moisture of about 0.2 to 0.3 atmospheric tension at 15 cm soil depth which comes to nearly 63 per cent available water and has found to be optimum for better crop yields.
  • The depth of irrigation must be limited to about 25 mm which is equal to value CPE (Cumulative Pan Evaporation) for scheduling irrigation but such a shallow irrigation can be done through drip and sprinkler irrigation systems only.
  • The farmers practice is to irrigate the furrows by 5.0 to 7.5 cm deep water which results into hardly 46 per cent water use efficiency or even low.
  • A saving of 38 per cent water could be obtained by irrigating alternate furrows.
  • Potato crop requires frequent and light irrigation at low moisture tension, irrespective of the varieties.
  • This is particularly important with new varieties which produce large tubers.
  • It is, therefore, important to keep the ridges moist but not wet which may be attained by giving irrigation at regular intervals.
  • Accordingly the first irrigation should be light and given 7-10 days after planting or even earlier depending upon soil moisture content.
  • The subsequent irrigation should be moderate to heavy which should cover 2/3rd to 3/4th height of ridge.
  • The intervals in subsequent irrigations could be about 15 days in heavy soils and 10 days in light soils.
  • Over flooding results in soil compaction of the ridges which results into poor aeration and poor tuber development.
  • The crop should be given light irrigation if frost is expected.

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Karnataka