Effects of Foliar Applications of Sulfur, Nitrogen and Phosphorus on Castor Bean (Ricinus cmmunis L.) Seed Yield and its Components under Water Deficit Conditions

To determine the effects of foliar applications of some macroelements on castor seed yield and its components under drought stress conditions, an experiment was conducted at the Agricultural Research Center of East Azerbaijan province. A factorial experiment, based on randomized complete block design with three replications, was carried out during 2013 growing season. Treatment factors consisted of irrigations with two levels (no water deficit and water deficit during grain filling stage) and of foliar applications of macroelements with four levels [control, wettable sulfur (0.2 percent), nitrogen (urea: 0.6 percent) and phosphor (super phosphate triple: 0.4 percent). Traits studied were: plant height, number of inflorescence, number of lateral branches, number of leaves, leaf temperature, relative water content, number of seeds per plant, 1000-kernal weight and seed yield. All traits, except number of inflorescence, were affected significantly by drought stress. Water deficit reduced plant height, number of leaves, number of seeds per plant, 1000-kernal weight, seed yield, relative water content, while it increased leaf temperature. Number of lateral branches was affected significantly by interaction between factors. Maximum latral branches (1.86) were obtained under non-stress treatment with nitrogen foliar application. Moderate drought stress had significant effect on leaf temperature and relative water content. It seems that, these traits can be used in determination of water deficit effects on castor bean.