Effect of water stress and different nitrogen levels on some Agronomic characters of Castor bean

This study was conducted to evaluate of water stress and different nitrogen usage effects on yield and yield components of castor bean, as a factorial experiment based on Random Complete Block (RCB) Design. In this study irrigation and nitrogen factors were evaluated in four levels with three replications which irrigation levels were normal irrigation, water holding in stemming, flowering and seed filling stages and also nitrogen usage levels were 0, 60, 120 and 180 kg/ha, respectively. The studied characters were plant height, leaf number, main stem length, stem diameter, node number in main stem, seed yield, seed oil percentage and seed oil yield.The results indicated that different water stress treatments of had significant effect and nitrogen usage on all of studied traits (P=0.01).The interaction of water stress and nitrogen usage factors was significant in all of traits (P=0.01). According to the results, the highest seed yield and seed oil yield were in normal irrigation level (1.992 and 1.035 ton/ha, respectively) and the level of 180 kg/ha nitrogen usage (2.566 and 1.292 ton/ha, respectively). Also the least amount of seed yield and seed oil yield was in water holding level in the stemming stage and no usage of nitrogen. Totally between experimental treatments, the highest seed yield and seed oil yield were in 180 kg/ha nitrogen usage and normal irrigation levels.