GROWTH AND HISTO-CHEMICAL RESPONSE OF <em>GMELINA</em> <em>ARBOREA</em> SEEDLINGS TO APPLICATIONS OF N AND K FERTILIZERS AND THEIR COMBINATIONS ON OXISOLIC SOIL

Abstract

The effects of N and K fertilizers and their combinations on the growth, physical and histo-chemical properties of Gmelina arborea seedlings on an oxisolic soil were investigated. The results obtained showed that NK combinations contributed significantly to the height growth, while N alone and NK combinations promoted radial growth and dry matter production. All the treatments improved the wood specific gravity of the seedlings. NK combinations also increased significantly fibre length, but most of the treatments did not affect fibre diameter and lumen size, while all the treatments significantly increased fibre wall thickness. Most of the treatments significantly enhanced slenderness ratio, and produced significantly higher Runkel ratio. Wood pH was lowered by all the tratments except when K was applied alone. Higher levels of K alone or in combination with N brought about significantly higher wood ash content. Soluble substances of the wood were increased by the individual applications of N and K. On the basis of holistic assessment, N3K1 , N3K2 and N3K3 were the best nutrient combinations for the growth of G. arborea seedling, while most of the treatments did not affect the histo-chemical properties relevant to pulp and paper production.