Studies on the mineral nutrition and fertilization of the passion fruit plant (Passiflora edulis f. flavicarpa): II - placement of fertilizer phosphorus

Abstract

1 - Tagged superphosphate was applied to 2.5 year old passion fruit plants from a commercial plantation established in a sandy loam. 2 - 100 grams of the fertilizer were distributed in the following ways: in a circular furrow 20 cm deep around the plant 40 cm from the stems; in a circular strip 10 cm wide, 40 cm from the stems; in six holes around the plants, 40 cm from the stems 20 cm deep, 2.5 cm in diameter. 3-10 grams of the fertilizer in 1 l of water were sprayed to the leaves. 4 - Three weeks after the treatments were made leaf samples were taken for analysis. 5 - Determinations of specific activities both in the leaves and in the fertilizer used have shown that P in the plant was derived from the superphosphate m the following relative proportions (by making the first treatment equal to 100): circular furrow = 100; circular strip = 120; holes = 30; foliar spray = 230.