Trial on the Production and Use of Compost Made from Pterygota bequaertii Crushed Material and Terminalia ivorensis a Chev Crushed Material for the Production of Gmelina arborea Seedlings : A Study from Daloa, Central Western Côte d'Ivoire

The over-exploitation of natural resources in the semi-deciduous forests of the Côte d'Ivoire forest zone has led to the degradation of the vegetation cover. This has reduced the ecological continuity of the semi-deciduous forest biomes in the forest zone. To restore these ecosystems, plantations of agroforestry species are recommended. However, nursery production of these types of trees using seed or vegetative propagation techniques faces a number of problems, such as the use of substrates with unfavourable physico-chemical properties and often contaminated with pathogens. This article presents the results of a trial conducted at the UJLOG experimental plot in Daloa to produce and evaluate the agronomic characteristics of compost made from Pterygota bequaertii and Terminalia Ivorensis A Chev for the production of Gmelina arborea seedlings. To this end, after the compost was made, four compost-based substrates and a forest humus-based control were prepared, characterised from a physical and chemical point of view and tested in the nursery. Seedling growth and root regeneration capacity measured in the nursery, as well as recovery after planting, were the parameters used to judge the quality of the seedlings and the effect of the compost. The results show that pterygota bequaertii and Terminalia Ivorensis A Chev have good composting properties, and their compost can be easily produced with or without a stimulator. The behaviour of the plants in the five substrates also showed that significant qualitative improvements were recorded in the plants reared in the compost-based substrates compared with the control plants. The results obtained show that the constituent elements of the substrates (droppings, bursa, carbonised sawdust) combined with pterygota bequaertii grindings and Terminalia Ivorensis A Chev grindings, depending on how they are prepared, have a significant effect on the physico-chemical parameters recorded (pH, total porosity, aeration and retention porosity, electrical conductivity, nitrogen, phosphorus, etc.); electrical conductivity, nitrogen, phosphorus and potassium), and consequently, on germination (germination percentage) and vegetative behaviour (height, diameter, number of leaves and robustness ratio), as well as a better root regeneration capacity and a better recovery of the Gmelina arborea plants in the field compared with the control plants (forest compost). It is therefore possible to improve the quality of Gmelina arborea seedlings by using pterygota bequaertii compost and Terminalia Ivorensis A Chev as a growing medium instead of forest compost.