Effects of Spacing, Nitrogen and Hormone Treatment on Pineapple in Swaziland

Abstract

SummaryPlant populations, nitrogen levels and the use of alpha naphthalene acetic acid (ANA) to rein-force natural flower differentiation were compared in a field experiment at Malkerns in the Swaziland Middleveld. Yield was raised by increasing plant population above 17,000 plants per acre, but reached a maximum at 23,000 plants per acre. Increased yield from denser planting occurred at the expense of fruit size and fruit set, and of sucker and slip production. Hormone counteracted the depressing effect of denser planting on fruit set and denser planting reduced sunburn damage and raised fruit acidity. 400 lb N per acre per crop increased yield over 200 lb N by increasing fruit size in the mother crop, and by increasing fruit size and set in the ratoon. Added nitrogen markedly reduced fruit acidity. ANA improved fruit set and therefore yield, without detrimental effects on fruit shape or quality. There are grounds for small increases in population above 17,000 plants per acre, for the use of ANA to reinforce natural flower differentiation and for the cautious use of the higher level of nitrogen fertilization.