Effect of limited irrigation regime and nitrogen fertilizer on the yield and yield components of sorghum var. Payam.

To study the effect of limited irrigation regime and nitrogen fertilizer on the yield and yield components of sorghum var. Payam، a field experiment was conducted in 2008 at experimental farm of college of agronomy and plant breeding، university of Zanjan. The experimental design was a split Plot based on a randomized complete block design with three repetitions. In this research four irrigation regime including full، light limited، moderate limited and severe limited irrigation، were assigned to the main plots and five nitrogen level including 0، 50، 100، 150، and 200 Kg/ha were assigned to the sub plots. The results showed that irrigation regimes and nitrogen fertilizer had significant effects (p≤ 0. 05) on grain and biological yield and yield components of sorghum. Grain and biological yields decreased with decrement in irrigation frequency from full to severe limited irrigation and increased with increment in nitrogen level from 0 to 200 kg/ha. The highest grain yield (8. 43 ton/ha) was obtained from 200 kg/ha nitrogen and full irrigation regime that had not any significant difference with 150 kg/ha nitrogen and full irrigation regime. The lowest grain yield (4. 6 ton/ha) was obtained from 200 kg/ha nitrogen and severe limited irrigation regime.