Effect of substrates and water supply on the survival and growth of Beilschmiedia mannii

Beilschmiedia mannii (spicy cedar) is an underutilized agroforestry species despite its organs being used for food, energy, and to cure various ailments. Very little effort has been made towards its domestication and the development of techniques for its production. An experiment was conducted in Benin, to evaluate the effect of substrate and water supply on B. mannii’s survival and growth. A factorial design with two factors was set up in a randomized complete block with three replications. Three substrate types under five watering levels were tested. Data on collar diameter, and total height were collected over 4 months and used to calculate the current growth rates, which were analyzed using two-way ANOVA. The findings indicated that the species exhibited a generally sluggish rate of growth, with height increasing by less than 1 cm per month and collar diameter expanding by under 0.4 mm each month. This trend was consistent, irrespective of the type of substrate or the frequency of watering. Although no statistically significant effect was found between the modalities of the factors in isolation and their interaction on current height growth, the combinations of a watering every two days with sandy-loamy substrate mixed with cow dung and a watering every five days with bokashi substrate exhibited the best height growth performances, with increases of 0.22 cm and 0.24 cm per week, respectively. The availability of water has proven to be crucial for both survival rates and the growth of collar diameter, highlighting how essential water is for B. mannii.