Nutritional status of watermelon fertirrigation with nitrogen and phosphorus rates

Abstract

The objective of this work was to evaluate the effect of N and P2O5 rates through irrigation water on the uptake of macro and micronutrients by watermelon crop. The study was conducted at the farm Santa Luzia, in Mossoró, in the State of Rio Grande do Norte, Brazil (5° 05' 57"S e 37° 33' 16"W). The experimental design was completely randomized blocks with strip cropping (4 x 4) x 2, resulting and thirty two treatments with three replicates. The treatments consisted in the application of four N rates (0; 48; 121; 218 kg ha-1) combined with four rates of P2O5 (0; 88; 220; 397 kg ha-1) with two cultivars of watermelon. No deficiency of N, P, K, Ca, Mg, Fe and Mn in the watermelon leaves was found in any treatment, excepting Cu and Zn. The N and P2O5 rates, as well as the interaction, provide significant effect on contents of macronutrients in the watermelon leaves. Macronutrients most absorbed by the leaves of watermelon were N>Ca>K>Mg>P.