16-8-4, 25-7-7

0.2-0.4 kgs./plant/year

less than 3.5 years

14-4-9, 18-4-5, 20-8-20

0.6-0.8 kgs./plant/year

3.5-7 years

15-7-18,  21-7-14, 21-7-18

1-1.5 kgs./plant/year

over 7 years or after tapping period