Salinised water and nitrogen doses for growing castor beans

The castor bean tree (Ricinus communis L.) is a plant from the Euphorbiaceae family, which is highly adaptable to a variety of climatic conditions, as well as being resistant to water deficit and being able to grow in a variety of soils. With this in mind, the aim of this research was to assess the effect of different levels of salinity in irrigation water, combined with doses of nitrogen fertiliser, on the growth and production components of the BRS Energia papaya plant, grown in lysimeters under field conditions. The treatments consisted of a combination of five levels of electrical conductivity of the irrigation water (0.4; 1.4; 2.4; 3.4 and 4.4 dS m-1) and five doses of nitrogen (50; 75; 100; 125 and 150% of the recommended dose for the pot test). A randomised block design was used in a 5 x 5 factorial scheme, with three replications, giving a total of seventy-five experimental units. The salinity of the irrigation water reduces the growth of the BRS Energia papaya tree, as seen by the decrease in plant height, stem diameter, number of leaves and leaf area.