Productivity, nutrient uptake and profitability of hybrid sunflower (Helianthusannuus) as influenced by irrigation and fertilizer-management practices under sub-tropical climate of West Bengal

An experiment was conducted at farmer's field at Madandanga, Gayeshpur, Nadia, West Bengal during the winter seasons 2011–12 and 2012–13, to study the effect of water and nutrient-management practices on growth and yield of hybrid sunflower (Helianthus annuus L.). The experiment was laid out in split-plot design, assigning 3 irrigation levels in the main plot and 7 fertilizer treatments in the sub-plots. The experiment consisted of 21 treatment combinations replicated thrice. Results revealed that N₈₀P₄₀K₄₀B_1.5S₂₅ (80, 40, 40, 1.5 and 25 kg/ha of N, P₂O₅, K₂O, B and S respectively) treatment significantly and synergistically increased plant height at 100 days after sowing (DAS), leaf-area index at 75 DAS, total dry-matter accumulation at 100 DAS, crop-growth rate during 50–75 DAS, basal girth at harvesting and capitulum diameter of hybrid sunflower (9.6, 65.1, 49.7, 49.0, 11.6 and 11.9% higher values than the crop in farmer fertilizer practice (FFP) plot respectively). The yield attributes, namely filled seeds/capitulum, filled seed weight/capitulum, total seed weight/capitulum and 100-seed weight, were significantly higher by 52.8, 63.5, 38.6 and 16.9% when grown with 3 irrigations, given at 30, 60 and 80 days after sowing (I_30/60/80) than the plants receiving 1 irrigation (I₃₀) and 75.7, 73.2, 97.8 and 30.0% with N₈₀P₄₀K₄₀B_1.5S₂₅ treatment than the FFP plots. Average seed and stalk yield of sunflower ‘Aditya ’was the highest in I_30/60/80 treatment, accounting 44.1 and 78.8% more than the crop yield obtained under I₃₀ treatment, respectively. Application of N₈₀P₄₀K₄₀B_1.5S₂₅ resulted in significantly higher seed and stalk yield (38.6 and 48.1% more than the values in FFP plots). Irrigation with I_30/60/80 resulted 1.2% more oil percentage compared to the I₃₀ treatment. The oil content of tested cultivar was significantly and synergistically increased by the application of N₈₀P₄₀K₄₀B_1.5S₂₅, accounting 6.4% more than that obtained with FFP. Irrigation × fertilizer interaction had significant effect on oil content and the highest value was observed to be in seeds obtained in plots fertilized with N₈₀P₄₀K₄₀B_1.5S₂₅ under 2 irrigations (I₃₀/₆₀). The maximum net return and benefit: cost ratio were recorded with the crop irrigated thrice (I_30/60/80), accounting 118 and 35%, respectively, more over the crop irrigated once (I₃₀). Irrespective of irrigation levels, combined application of NPK and B (N₈₀P₄₀K₄₀B_1.5) resulted in the highest net returns and benefit: cost ratio among all fertilization practices, accounting 52 and 23%, respectively more over the crop fertilized with N₆₀P₃₀K₃₀ (FFP).