Abstract

                                A field experiment was conducted during 2006-2009, on 29 years old East Coast Tall (ECT) coconut palms at Coconut Research Station, Veppankulam to explore the possibility of nitrogen substitution through organic manure. It was aimed to substitute 50 per cent of recommended nitrogen through organic manure. There were five treatments viz., T 1 - Absolute control, T 2 - Recommended NPK (560:320:1200 g/palm/year), T 3 - 100% N as Composted Coir Pith (CCP) + balance PK as fertilizer, T 4 - 50 % N as CCP + balance NPK as fertilizer and T 5 - Neem cake (10 kg) + ash (20 kg), bonemeal (2kg). The experimental results proved that 50 % nitrogen substitution through organic manure (CCP) and remaining 50 % nitrogen through fertilizers (T 4 ) recorded comparable mean annual nut yield (111 and 117 nuts / palm / year, respectively, in 2008 and 2009) and other yield contributing parameters viz., no. of functional leaves, no. of bunches and no. of female flowers, with 100% NPK through fertilizers (T 2 ). However, the soil fertility viz., soil available NPK and index leaf NPK content were significantly higher due to chemical fertilizers at their recommended level. Hence, in coconut nutrition, 50 per cent nitrogen can be substituted through organics (CCP) and this may pave the way for gradual replacement of chemical fertilizer in coconut garden in the long run by way of waste recycling.

Key words : Integrated Nutrient Management, composted coil paith, coconut yield, economics.