Question: asking about the age of arecanut seedling for transfering in the main field and amount of fertilizer dose to be apply per plant. 
Answer: transplant the seedlings in the main field at the age of 12-18 months. dig a pit at a depth of 90 cm apply 5kg of manure in the pit. again 100gm of urea, 125 gram of phosphorus, 115 gram of potash and 25 gram of borax per plant in a ring method,1 miter away from the plant. 

in coconut plant fertilizer dose:  urea 1200 gram, phosphorus 2 kg, potash 2 kg and borax 50 gram per plant in a ring method 1.5 to 1.8 meter away from the plant. make two part of these fertilizer. apply one part in the month of june- july and other part in the month of december-january.