Growth and production of castor bean under different levels of irrigation water salinity and nitrogen doses

Abstract

The castor bean (Ricinus communis L.) is a plant belonging to the family Euphorbiaceae, and stands for the rusticity and adaptation to adverse conditions of climate and soil, for the fast growth, high production and considerable oil content in its seeds. In this context, this study we conducted to evaluate the effect of different levels of irrigation water of salinity and nitrogen on the growth and yield of castor bean cv. BRS Energia. The experiment was conducted in lysimeters under field conditions, at the Centro de Ciências e Tecnologia Agroalimentar, of Universidade Federal de Campina Grande. A complete randomized block design in a 5 x 5 factorial design with three replications. Treatments included a combination of five levels of electrical conductivity of 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). The number of leaves, stem diameter, plant height, dry mass of stems and leaves, and fruit number in primary raceme of castor bean cv. BRS Energia were linearly and negatively affected by irrigation water salinity from 0.4 dS m-1, the dry mass of leaves and production of primary cluster are variables more sensitive to salt stress, increasing doses of nitrogen fertilization promoted at harvest, increase in dry weight of stem and leaves and number of fruit in primary cluster; applying increasing doses of nitrogen reduced the effect of salinity on stem diameter of castor bean cv. BRS Energia.