Browsing by Author "Varadan, K.M."

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    Water Management Studies On Coconut In India
    (1991) Mohammed Yusuf; Varadan, K.M.
    Variability of rainfall, coupled with inadequate irrigation resources and poor water management are the main causes of low productivity of palms even in traditional coconut growing states. Studies based on climatological approach at Kasaragod revealed that water requirement (W.R.) of adult palm is equal to the potential evaporation (Eo). Lysimetric studies at CWRDM, Calicut have shown that evapotranspiration (EX) rate of a five-year old palm increases from 2.9 mm/day in December to 5.5 mm/day in April and falls to 2.3 mm/day in June. At Coimbatore, the transpiration rate of coconut leaves was measured to be 7.5 ug/cm /sec. and the estimated W.R. ranged from 55 1/day in December to US 1/day/palm in June. An annual increase of 31 nuts/palm/year at Nileshwar was due to basin irrigation with 3001 at five days interval in sandy loam soil. In littoral sand, flood irrigation with 5 cm depth increased yield by 85.4 nuts/palm/year over pre-irrigation yield. At Kasaragod, irrigation with 20 mm at Irrigation Water (IW): Cumulative Pan Evaporation (CPE) ratio of 1.00, recorded the highest cumulative yield of 918 nuts/palm after 16 years of planting. At Calicut, irrigation with 30 or 45 mm of water at IW: CPE ratio of 1.00 resulted in significant improvement in yield of West Coast Tall palms when practiced along with mulching. Studies at Kasaragod have shown that in heavy rainfall areas, sea water can be used for irrigating coconut palms without any adverse effect on productivity of palms and soil conditions. Drip irrigation has been found most suitable for water scarcity areas. In littoral sandy soil at Kasaragod, 32.1/palm/day through drip, produced 38 per cent higher nuts than basin irrigation with 2001 per four days. Considerable improvement in productivity of palms under tainted conditions have been reported through practices controlling run off, increasing infiltration, conserving soil moisture etc.