Influence of Cattle Dung and Biochar Amendments on Yield and Oil Content of Sunflower (<i>Helianthus annus</i> L.)

This research was carried out to investigate the effects of different application levels of cattle dung, cattle dung biochar, and NPK on the yield and oil content of sunflower. Two field experiments were conducted at the Teaching and Research Farm of the University of Ilorin, using split plot arrangement within a randomized complete block designs (RCBD) and replicated three times. The main plots contained nutrient sources (cattle dung and cattle dung biochar), while sub-plots contained varying levels (0, 5, 10, 15, 20 Mgha⁻¹ and NPK 300 kgha⁻¹), resulting in 12 treatment combinations. Cattle dung and cattle dung biochar significantly enhanced yield parameters and oil content compared to control. Biochar performed better than cattle dung but mostly not significantly, interaction effects were also not significant. Plots that received 20 Mgha-1 had the highest values for oil content (49.36% and 52.05%), number of seeds per head (929.79, 969.44), yield per plot (3127.96g, 3193.05g), yield per hectare (1251.18kg, 1277.22), and the fastest days to 50% flowering (82.70, 86.54); 15 Mgha-1 had the highest flower head diameter (204.75mm, 220.09mm), while NPK had the highest 1000 seed weight (71.04g, 80.38g). Control consistently had lower values than the averages recorded for the treatments. Both cattle dung and biochar improved seed production without compromising seed size and weight, highlighting their potential as environmentally friendly alternatives to chemical fertilizers.