Effect of Foliar Nutrient Application on Morphophysiological Characteristics of Castor (Ricinus communis L.) at Different Levels of Water Deficit

To study the effect of irrigation levels and spraying of chemical fertilizers on some Morphophysiological traits in castor oil plant an experiment was conducted in East Azarbaijan Agricultural Research and Education Center, Tabriz- Iran at the 2017 crop season. The field experiment was carried out by a split-plot design based on a completely randomized block design with three replications. The first factor was irrigation levels consisting of control (normal irrigation), irrigation after 80 mm and 140 mm evaporation from the pan evaporation in asseinged to main plots and eight spraying chemical fertilizers including sulfur, potassium, nitrogen, sulfur + potassium, sulfur + nitrogen, potassium + nitrogen, sulfur + potassium + nitrogen and control to subplots.The results showed that the effects of irrigation levels and chemical fertilizer treatments on all traits were significant furthermore, the interaction of two treatments were also significant on all traits except chlorophyll index. Irrigation interval after 140 mm evaporation reduced the leaf chlorophyll index by 18.25% compared to normal conditions. Also, spraying S + N + K increased this trait by 14.90% compared to the control treatment. The highest plant height (135.15 cm), number of leaves (25.12), stomatal conductance coefficient (276.55 Mmol.m2sec), number of branches (7.25), biomass (1.60 kg.m2) and grain yield (0.45 kg.ha-1) and the lowest proline content (0.19μmol.g-1) were recorded by spraying plants with S + N + K under normal irrigation condition. Spraying plants with S+N +K under irrigation interval after 80 and 140 mm also increase grain yields by 45.83 and 40.0 percent respectively, compared with control treatment and it was able to modify the effect of water deficit on traits under study.