Influence of macronutrient acumulation of “Magnum” watermelon by phosphate doses and aplication maners in calcareous soil

Abstract

Information on the nutritional need of the watermelon crop is required particularly for P, due to the dynamics of this element in the soil and its low availability in many soils in the semi-arid region. The objective of this work was to evaluate the biomass production and the macronutrient extraction of the cv. Magnum irrigated under the influence of phosphate fertilization. The experiment was carried out in a medium textured Cambisol in Upanema, state of Rio Grande do Norte, in a randomized block experiment design, using the split-plot factorial scheme with four replications. The treatments consisted of 76, 168, 275 and 397 kg ha-1 of P2O5, which were applied in two manners: F0 – 100% in pre-planting and F1 – in pre-planting + fertirrigation (50 kg ha- 1 as MAP). Two additional treatments were also applied: Adc1 – no phosphate; and Adc2 – with phosphate only in fertirrigation. Fertilization F1 provided greater accumulations of P and S, but, in general, the effects of the doses were dependent on the fertilization system, especially the treatments F0275 and F1168 regarding the accumulation of other nutrients.