Effect of irrigation and nitrogen on growth and yield of sunflower (Helianthus annuus)

An experiment on summer sunflower (Helianthus annuus L.) was conducted duri ng 1994-96 with 4 irrigation levels based on the ratio of irrigation water depth : cumulative pan evaporation (IW : CPE) and 4 nitrogen levels in Biha r. The results showed that seed yield increased significantly at IW : CPE r atio of 0.8 (1.49 tonnes/ha) with 6 cm depth comprising of 6 irrigation. Bu t water-use efficiency was higher at 0.6 ratio with 4 irrigation. Response to nitrogen was recorded only up to 40 kg N/ha. Plant height, dry-matter/pl ant and capitulum diameter were maximum at 0.8 IW : CPE ratio. But 1000-see d weight increased only at IW : CPE of 0.6 and 40 kg N/ha. Total nitrogen u ptake and net return were also highest at 0.8 IW : CPE ratio and 40 kg N/ha . Soil-moisture depletion was higher from 0-60 m layer with 4-6 irrigation, whereas relative depletion in lower soil profile (60-90 cm) was more in ra infed control.