Fertigation of newly planted ‘Queen Cox’/M.9 apple trees: Establishment, early growth and precocity of cropping

Abstract

The effects of a compound soluble 19:6:6 fertilizer applied in trickle irrigation (fertigation) at rates between 10 and 80 g N per tree per year were compared with irrigation alone, broadcast fertilizer at 80 g N per tree per year and no fertilizer or irrigation on trees planted in 1987. Trees receiving irrigation had shoot growth similar to the unirrigated trees either with or without broadcast fertilizer except in 1990 when irrigation substantially increased shoot growth compared with the other two treatments. Trees receiving fertigation at 10 and 20 g N per tree had similar total shoot lengths to those receiving irrigation but fruit set on spur and terminal flower clusters was increased and this was reflected in an increased cumulative yield of apples from 1988-90. Compared with all other treatments, fertigation at 40 and 80 g N per tree caused large increases in total shoot growth associated with an excessive production of axillary floral buds that abscinded leaving unproductive bare wood. Yield of ap...