Contribution of soil macro-fauna diversity and abundance to soil fertility enhancement in cocoa-based (Theobroma cacao) agroforestry systems in the Littoral Region of Cameroon: An appraisal of cocoa farmers local knowledge

Soil macro-fauna diversity and abundance greatly influence soil fertility. However, little has been done to confirm this hypothesis in cocoa-based agroforestry systems. It was in this light that this research work was undertaken in order to fill the knowledge gap. Through the use of a mixed research method for data collection and appropriate data analysis procedures, findings showed that diverse soil macro-fauna were identified by cocoa farmers in cocoa-based agroforestry systems with the main being earth worms (100%), ants (100%), termites (70%), millipedes (50%), centipedes (50%), and snails (60%). Most cocoa farmers perceived that soil macro-fauna diversity in cocoa-based agroforestry systems was high (58.3%) and very high (17%) respectively. Earth worms, ants, millipedes, centipedes, spiders, harvestmen and scorpions were perceived by most cocoa farmers (44%, 38.3%, 43.3%, 41.3%, 55.6%, 53.3% and 48% respectively) to have a high level of abundance in cocoa-based agroforestry systems. A statistically significant direct non-causal and causal relationship (p<0.05) existed between soil macro-fauna diversity and soil fertility enhancement in cocoa-based agroforestry systems, implying that the higher the diversity, the higher the level of soil fertility and the lower the diversity, the lower the level of soil fertility enhancement. Concerning soil macro-fauna abundance, a statistically significant direct non-causal and causal relationship (p<0.05) existed between soil macro-fauna abundance (i.e. for earth worms, ants, termites, beetles, crickets, woodlice, snails and slugs) and soil fertility enhancement in cocoa-based agroforestry systems, implying that the greater the abundance of these soil macro-fauna, the greater the fertility of the soil. It is recommended that measures be taken to ensure soil macro-fauna diversity and abundance in order to enhance the fertility of the soil in cocoa-based agroforestry systems.