Effect of organic and inorganic fertilizers on regeneration of seedlings of Ricinodendron heudelotii (Baill) Pierre et Pax.

Most soils in the humid tropical zones present a particular problem. Due to leaching, the fertilizer provided by the process of nutrient cycling in tropical rainforest is confined to the top few inches of the soil. Varying quantities of manure and NPK fertilizers were applied to assess their effects on the growth of Ricinodendron heudelotii seedlings, a non-timber-forest-product. Assessment was done by measurements of height, number of leaves, leaf area, seedling biomass, the relative growth rate, and the net assimilation rate. The effects of organic and inorganic fertilizers on plant height and number of leaves were not significant, though their effect on leaf area was significant (p<0.05). The total biomass, relative growth rate, and net assimilation rate under the different treatment combinations had no significant effect on yield. However, fertilizer treatments had a significant effect among the periods of application for the biomass and the net assimilation rate (p<0.05), but had no significant effect on the observation period for the relative growth rate.Keywords: Manure, NPK, non-timber-forest-product, biomass, relative growth rate, net assimilation rate