Nitrogen, phosphorus and potassium nutrition on ornamental Ipomoea purpurea growth

Abstract

The study aimed to evaluate the effect of nitrogen, potassium, and phosphorus on I. purpurea growth. Plants were weekly fertilized with 50 mL of Hoagland & Amon (1950) modified nutrient solution as follow: Nitrogen solution with 0, 0.0888, 0.2001, 0.6003 or 1.801 g L-1 of ammonium nitrate; Phosphorus solution with 0, 2.1, 5.5, 10.3 or 13.5 mL L-1 phosphoric acid, and Potassium solution with 0, 0.3728, 1.1183, 1.8638 or 2.2065 g L-1 potassium chloride. I. purpurea showed high demand for N, reflected on an increase of leaf area. Higher concentration of N promoted preferential investment in photosynthetic areas, as confirmed by the leaf/root ratio. I. purpurea is responsive P fertilization, mainly to promote stem and root growth. I. purpurea was not responsive to K fertilization. The results showed that fertilization with 0.2001 g L-1 ammonium nitrate and 5.5 mL L-1 phosphoric acid is recommended for I. purpurea cultivation.

Keywords

• floriculture. morninglory. mineral nutrition. npk.