Enhancing sunflower yield by identifying phosphorus fertilizer requirements in the Eastern Ganges delta coastal ecosystem
Mohammad Asadul Haque, Md Jahiruddin, Md Fazlul Hoque, Md Baktear Hossain, Md. Enamul Haque, R.W. Bell
Abstract
Sunflower (Helianthus annuus L.) has recently been identified as a promising crop for the seasonally-fallow lands of the coastal region of the eastern Ganges delta; but its fertilizer requirement especially phosphorus (P) for higher yield has not yet been determined. The objectives of the experiment were to find out the optimum P rate which maximizes yield and P use efficiency with minimum positive P balance in soil. Accordingly an experiment was conducted in 2020, 2021 and 2023 using eight P rates having 0, 7.2, 14.4, 21.6, 28.8, 36.0, 43.2 and 50.4 kg P ha−1 in sunflower. The significantly higher achene yield over the years was found in 21.6 to 36.0 kg P ha−1, and 28.8 kg P ha−1 on a pooled yield basis and this rate had a minimum positive P balance (5.9 kg P ha−1). At 28.8 kg P ha−1, the partial factor productivity varied from 90 to 127, and agronomic efficiency of 22 to 49 kg achene kg−1 added P over the years. The P requirement in the coastal ecosystem was lower compared to inland agricultural soils. The 28.8 to 36 kg P ha−1 rate could be sufficient to meet P requirements of sunflower while maintaining P status in salt-affected coastal soils of the eastern Ganges delta.