Effect of Fertilizer Level and Planting Distance on Soil pH, Growth, Fruit Size, Disease Incidence, Yield, and Profit of Two Papaya Varieties

Abstract

Papaya production in Puerto Rico is low, probably because of diseases and poor management practices. In this study, high yielding varieties were used to compare planting distances and fertilising practices. Plants of varieties PR 6-65 and PR 7-65, planted at 1.8 x 1.8 m were significantly larger than those at 1.2 x 1.2m. The larger size of the plants was reflected in an increase in fruit yield and net profit. PR 6-65 produced a significantly heavier crop and a higher net profit/ha than PR 7-65. PR 6-65 was significantly more susceptible to the Isabela mosaic disease and more tolerant to bunchy top than PR 7-65. Soil pH was significantly lower at the 1.2 x 1.2m planting distance than at the 1.8 x 1.8 m, probably because more fertilizer was used in the closer planting. There were no significant differences between the mean yields of papaya plants receiving monthly applications of .227 and .454 kg of a 15-15-15 fertilizer, suggesting that the smaller amount of fertilizer is enough to produce a heavy crop and obtain a good net profit from papayas grown in Coto clay, an Oxisol.