Influence of inorganic fertilizer on the early growth and nutrient concentration of bush mango (Irvingia gabonensis var. wombulu L.)

Irvingia gabonensis also known as bush mango or dika nut is one of the highly useful fruit trees that is being classified as endangered species. So most past efforts on this crop has been on conservation. Recently, it was discovered that its long gestation period can be reduced by budding. Budded seedlings of Irvingia are in short supply and there is need to accelerate seedling growth for attainment of buddable size. The main objective of this study was to provide an empirical analysis to nutrient requirement of irvingia at nursery/seedling stage. A greenhouse experiment was conducted to evaluate the effect of fertiliser on the growth and nutrient concentration of Irvingia. The fertilizer was applied at the rate of 0, 30, 60, 90 and 120 kg NPK ha^‑1, The results revealed that with the exception of number of leaf, the growth parameters of Irvingia were not significantly influenced by NPK fertilizer before 12 weeks after transplanting (WAT). At 12 WAT, stem girth and number of leaf were significantly increased with increase in fertilizer rates up to 90 kg ha^‑1. While the concentration of nitrogen (N) in the leaf, stem and root showed no significant increase, the phosphorus (P) in the leaf, stem and root of the seedlings was significantly influenced by the fertilizer application up to 120 kg ha^‑1. Similar influence was obtained in the concentration of potassium (K) in the stem and root but not in the leaf of Irvingia seedling. In conclusion, this study revealed that application of inorganic fertilizer up to 90 kg NPK ha^‑1 does influence the growth of Irvingia. Though initial response was slow, the application will on the long-run reduce the gestation period by reducing the time taken to reach buddable size.