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Water requirements of the sugar cane

This paper reports and discusses results referring to a field trial set up to determine the water needs of the sugar cane. Soil samples were taken from five locations at approximately two-week intervals and at the depths of 0-25, 25-50, 50-75 and 75-10 cm for soil moisture determination. The wilting point and moisture equivalent values used in the experiment were the same as determined for coffee plant experiments. Most of the roots of the sugar cane are found in the upper 50 cm of the soil. If we assume an average of 52 mm stored in the root zone as available to the crops and one plans to irrigate when seventy per cent of available moisture is used up in order to allow for unevenness in root and water distribution in the soil, the irrigation should be scheduled when the crop has used 36 mm of the soil moisture storage. With an average use of 3.0 mm per day during the dry season, irrigation is required about every twelve days unless moisture is replenished by rainfall. For the required replenishment of 36 mm of moisture it is necessary to apply about 60 mm, if the irrigation efficiency is calculated at a 60 per cent level.


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