Growth and Yield Response of Thevetia periviana J. to Applied Nitrogen and Phosphorus Fertilizers in the Southern Guinea Savannah of Nigeria

A field experiment was conducted during the 2010 rainy season to study the growth and yield response of Thevetia peruviana J. to rates of nitrogen and phosphorus fertilizers at the Research Farm of the Bio-fuel and Alternative Renewable Energy Ltd., Edidi, Kwara State in the Southern Guinea Savannah of Nigeria. The treatments were combined in split plot and laid out in Randomised Complete Block Design with three replicates. The experiment comprised of nine treatments combination of three levels of nitrogen fertilizer (control, 30 and 60 kg N ha-1), three levels of phosphorus fertilizer (control, 30 and 60 kg P2O5 ha-1) and one plant population (2,500 plant ha-1) at 2 m by 2 m plant spacing. The results indicated that 30 kg P2O5 ha-1 rate of phosphorus fertilizer increased plant height, number of branches, stem girth, reduced number of days to flowering and fruit maturity and increased fruit yield which were statistically similar to application of 60 kg P2O5 ha-1 rate of phosphorus fertilizer. It can therefore be concluded that 30 kg P2O5 ha-1 rate of phosphorus fertilizer is appropriate in enhancing the fruit yield of thevetia. Further increase in phosphorus fertilizer to 60 kg P2O5 ha-1 will not be economical as it will amount to waste of fertilizer.