Effects of Nitrogen and Phosphorus Fertilizer on Agro- Morphological Traits and Yield Performance of Gum Bush (<i>Thevetia peruviana</i> J.) in Southern Guinea Savanna Zone of Nigeria

Abstract

Growth and yield parameters of Thevetia peruviana J. were evaluated under varying rates of nitrogen and phosphorus fertilizers at the Research Farm of the Bio-fuel and Alternate Renewable Energy Ltd., Kwara State in the southern guinea savanna zone of Nigeria. Three levels of phosphorus (0, 30 and 60 kg P₂O₅ ha^-1) and three levels of nitrogen (0, 30 and 60 kg N ha^-1) were tested. The experimental design was a factorial in Randomized Complete Block replicated three times. Nitrogen fertilizer rate of 60 kg N ha^-1 significantly produced higher values for plant height, number of primary branches, number of days to fruit maturity and dry weight of 10 seeds than the control which was statistically similar with fertilizer application of 30 kg N ha^-1. Number of days to first flower appearance and number of harvested seeds were also found to increase significantly with application of 60 kg N ha^-1. The effect of application of 0 kg P₂O₅ ha^-1 was not significant on any of the tested parameters but the application of 30 kg P₂O₅ ha^-1 increased plant height and number of primary branches which was not significant with other phosphorus rates. It was also observed from the study that application of 60 kg P₂O₅ ha^-1 reduced the number of days to first flower appearance, number of days to 50% flower appearance, increased seed length, seed diameter, dry weight of 10 seeds and number of harvested seeds. However, all these parameters were statistically similar when 30 kg P₂O₅ ha^-1 was applied. Application of 60 kg N ha^-1 and 30 kg P₂O₅ ha^-1 is therefore recommended for enhanced growth and seed yield.

Keywords:- Nitrogen and phosphorus fertilizer, Growth, Yield and Thevetia peruviana,