Cattle manure and biological fertilizer enhance growth and nutrient accumulation in African mahogany seedlings (Khaya ivorensis)

The production of high-quality forest seedlings is essential for successful reforestation programs, particularly for high-value timber species such as African mahogany ( Khaya ivorensis ), which is widely cultivated due to its rapid growth and economic importance. This study evaluated the effects of sustainable substrate compositions and biological fertilizers on seedling growth and nutrient accumulation under greenhouse nursery conditions. A pot experiment was conducted in a completely randomized design with ten treatments, using substrates composed of soil, sand, and cattle manure in different proportions, with or without the application of a biological fertilizer obtained through microbial fermentation of cattle manure. Seedling performance was assessed five months after sowing based on plant height, stem diameter, number of leaves, dry shoot mass, and macronutrient accumulation in the whole plant. Substrate combinations containing cattle manure significantly outperformed manure-free substrates, with Soil + Sand + Manure (1:1:1) and Soil + Manure (1:1) consistently producing the highest growth parameter and nutrient accumulation values. The application of biological fertilizer further enhanced nutrient accumulation, although its effects were independent of substrate composition. Overall, the results demonstrate that substrates enriched with cattle manure, with or without biological fertilizer, represent an effective and sustainable strategy for improving the growth and nutritional status of K. ivorensis seedlings in nursery production systems.