Response of sunflower (Helianthus annuus L.) to nitrogen and phosphorus application in the forest-savanna transition zone of south west, Nigeria
Field experiments were conducted during the late rainy-season cropping of 1999 and 2000 at the Teaching and Research Farm of University of Agriculture, Abeokuta (7o15' N, 3o25'E) in the forest-savanna transition zone of south west Nigeria to investigate the response of sunflower (vr. Funtua) to applied nitrogen (0, 30, 60 and 90 kg N ha-1) and phosphorus (0, 30 and 60 kg P ha-1) fertilizers. N significantly (P < 0.05) increased plant height when applied at 60 and 90 kg ha-1 compared to the control. N also significantly (P < 0.05) increased head weight, head diameter, achene weight per head, number of achene per head and grain yield relative to the control, but these agronomic characters were not affected significantly by P application. Nitrogen applied at 30, 60 and 90 kg N ha-1 significantly increased grain yield by 30, 40 and 50 %, compared with the control. Nitrogen x Phosphorus interaction significantly (P < 0.05) affected head weight, achene number per head and grain yield with N60P30 recording the highest grain yield (1580.68 kg ha-1), achene weight (27.99 g) and second highest head weight (63.76 g). Consequently, it was concluded that since application of N60P30 resulted in optimum performance of sunflower, these rates are therefore, recommended for sunflower production in the forest-savanna transition zone of south-west Nigeria.
Keywords: nitrogen, phosphorus, sunflower, transition zone, south west Nigeria
Nigerian Journal of Horticultural Science Vol. 10 2005: pp. 23-29