November-December 2025
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Effect of composting time of Tithonia diversifolia biomass on the physicochemical quality of the compost produced and on the growth of Terminalia superba (Engler and Diels) forest seedlings in a nursery

GROGA Noel, N’GANZOUA Kouamé René, KOUAME Amany Guillaume, KOUADIO Akessé Henri Maurice, YAO Kouakou Abessika Georges, SORO Dognimeton

ABSTRACT: Background: Faced with the disappearance and degradation of forests, and with them certain highly prized species of wood, the State of Côte d'Ivoire has taken several measures through a forest reforestation policy to achieve the goal of 20% forest cover by 2030. In this process, Terminalia superba is one of the main tree species to be reforested. Aims: The study aims to develop vigorous Terminalia superba seedlings in nurseries using Tithonia diversifolia-based substrates for reforestation in real environments. Place and duration of study: The study was conducted between October 2022 and May 2023 during the rainy season on one of the experimental plots of the Regional Directorate of Water and Forests of Duekoué, in the Guémon region, in western Côte d'Ivoire. Methodology: The methodology involved creating a nursery using a Fisher 4-block design. Each block comprises five basic plots in which 12 polyethylene bags containing different substrates are distributed (Tem = blank forest control; Tet = forest control with fresh Tithonia diversifolia; Cot1m = 1-month-old Tithonia diversifolia compost; Cot2m = 2- month-old Tithonia diversifolia compost; Cot3m = Tithonia diversifolia compost aged 3 months. In each bag, Terminalia superba seeds with high germination capacity were selected and sown directly at a rate of 2 seeds each, then watered. The parameters measured included physico-chemical analysis of Tithonia diversifolia compost and growth parameters of Terminalia superba. Results: The results showed that the substrates are porous (total porosity ˃ 50%; aeration porosity ˃ 20% and retention porosity ˃ 30%), have low acidity (6 ˂pH ˂8) and are very rich in nutrients (1180˂N(mg/g) ˂2840; 2212˂P(mg/g) ˂9540; 3421˂K(mg/g) ˂15240; 357˂Ca(mg/g) ˂440; 63˂Mg(mg/g) ˂226; 2514˂CE (mg/g) ˂5252; 0.02˂Sat(%)˂0.26). They induced a germination rate of up to 70% and significantly affected the growth parameters of Terminalia superba seedlings, with the best averages for collar diameter (35 to 37 cm), height (34.50 to 43.40 cm), leaf length (7.10 to 8.54 cm), leaf width (3.32 to 4.90 cm), and robustness ratio up to 6.53 after 14 weeks of sowing, especially for 2- to 3-month-old composts. Conclusion: It is noted that composted substrates based on Tithonia diversifolia after 2 to 3 months could be a promising alternative to traditional forest soil for producing vigorous nursery plants.

[ FULL TEXT PDF 1-11 ] DOI: 10.22587/ajbas.2025.19.6.1

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