Effect of irrigation and nitrogen on oil percentage, yield and water-use efficiency of winter sunflower (Helianthus annuus)

An experiment was conducted to study the influence of irrigation and nitrogen on oil (%) and seed yield of 'Arun Hybrid' of sunflower (Helianthus annuus L.). Significant increase in yield (17.4 and 18.0 q/ha) was recorded up to 3 irrigations with IW : CPE ratio of 0.8. Oil yield and net returns were also maximum at this level. The crop showed significant response up to 40 kg N/ha. The leaf-area index and other ancillary characters were also maximum in case of 3 irrigations and 40 kg N/ha. Oil (%) and water-use efficiency were higher at 1 irrigation but from the economic point of view, 3 irrigations resulted in more net returns. Soil-moisture depletion in 0-60 cm layer was higher than that in 60-90 cm soil layer, but the relative depletion in 60-90 cm layer was more in rainfed due to penetration of roots in search of soil moisture.