Single and combined nitrogen, phosphorus and potassium effects on the growth of sunflower (Helianthus annuus L.)

Abstract

A pot experiment with sunflower, Uruguai variety, was carried out an oxisol at Botucatu region, located in SP, Brazil, in order to verify the effect of different levels of nitrogen, phosphorus and potassium on the vegetative development of the plants. The height, number of leaves, dry and green matter weight of the different parts of the plants were markedly affected by the nitrogen, phosphorus and the NxP interaction. Potassium influence was observed on the dry matter weight of the stem and of the total aerial part of the plants and on the water weight of the foliar blades; these influences were observed only with the higher level of phosphorus (166 ppm).