Effect of inorganic fertilizer on the growth of Khaya senegalensis seedlings

Abstract

This study investigated the effects of two different mineral fertilizers on the early growth and biomass accumulation of Khaya senegalensis seedlings. The research was carried out in the nursery of the Department of Forest Resources Management, University of Ibadan, Nigeria. Uniformly growing seedlings were transplanted into polythene pots filled with 4kg topsoil and ten (10) grams each of NPK 15-15-15, Urea 46-0-0 and a combination of NPK15-15-15: Urea 46-0-0. Number of leaves, shoot height and collar diameter were assessed weekly for three months. Biomass, leaf area, leaf dry weight (LDW), stem dry weight (SDW), root dry weight (RDW) and total dry weight (TDW) of randomly selected seedlings from each treatment were determined 12 weeks after fertilizer application. Data collected were subjected to ANOVA. LSD was used to separate significantly different means. There was a significant difference in height of seedlings treated with NPK-UREA and other seedlings at 0.05 probability level. The seedlings treated with NPK-UREA had the highest mean height, 26.3cm at the 12^th week after fertilizer application. The highest mean collar diameter- 0.75cm, leaf area- 31.4cm² and biomass- 5.7g, were recorded in the control. This study shows that 10g of NPK-UREA fertilizers was not sufficient to increase the rate of growth of Khaya senegalensis seedlings above the seedlings with no fertilizer application.

Keywords: biomass accumulation, Fertilizer application, Indigenous trees, Khaya senegalensis.