Comparative Effect of Ectomycorrhizal Inoculation, Mineral and Organic Amendments and their Interactions on the Juvenile Growth of Afzelia africana in the Nursery

Abstract

Afzelia africana (Fabaceae) is one of the multipurpose plants native in tropical Africa, mainly used for its medicinal properties, fodder value and the quality of its wood. However, the species is highly threatened due to several factors including regeneration problems. This study aimed to assess the effect of ectomycorrhizal inoculation, organic and mineral amendments and their interactions on the juvenile growth of A. africana in a nursery. The experiment was laid out in a completely randomized design with twelve treatments and three replications. The treatments consisted of ectomycorrhizal inoculation namely uninoculated, inoculated with Scleroderma verrucosum or inoculated with Lactarius gymnocarpus, and organic amendment and mineral fertiliser NPK 13-10-10 in the soil. Growth parameters such as total height, stem diameter and phyllode number were recorded monthly for 5 months. The effect of different treatments on the growth performance of A. africana seedling was assessed by performing analyses of variance and the averages were compared using the Newman Keul test. For ectomycorrhizal inoculation, only S. verrucosum was able to increase growth parameters of A. africana and the effect was significantly (p<0.05) dependent on the type of adopted fertiliser. The highest values of growth parameters were obtained under the combination of S. verrucosum with 166 g of manure or 20 g of mineral fertiliser. It appeared that the combined application of fertiliser and inoculum of S. verrucosum on A. africana seedlings improved the growth of the plants in the nursery.