Effect of Planting Distance and Fertilizer Level on the Mineral Content of the Leaf of two Varieties of Carica papaya L.

Abstract

Ten-month-old papaya plants of variety P.R. 6-65 contained significantly more N, P, K and Ca, lower K and Mg in blades, than plants of variety P.R. 7-65, and equal content of Mn. The petioles in variety P.R. 7-65 had significantly more Mn and K, but less Mg and Ca than those of variety P.R. 6-65, and equal contents of N. N in the blades in the two varieties at two planting distances decreased, while N in the petioles increased as the age of the plants increased. The P content in the blades of plants of the two varieties and the two spacings decreased as the age of the plants increased, while in the petioles this reduction was significant only at the planting distance of 1.8 x 1.8 m. At the 1.2 X 1.2 m planting distance, the P in the petioles of variety P.R. 6-65 was not significantly affected by the plant age, but in variety P.R. 7-65 P increased significantly with the age of the plant. K in the blades and petioles of variety P.R. 6-65 at 10 and 23 months decreased significantly as the planting distance increased. In variety P.R. 7-65, similar results were found in 23-month-old plants but not in those 10 months old. The Ca and Mn content in the blades and petioles were not affected by the planting distance or by the fertilizer supplied to the plants. Mg in the blades of P.R. 7-65 decreased as the planting distance increased, and did not vary in variety P.R. 6-65; there was a significant interaction of fertilizer x distance. The significant second order interaction of fertilizer X distance x variety for the Mg content of the petioles suggests that the varieties responded differently to the fertilizer supplied at the two distances.