Concept:Cocoa is a perennial tree crop; its yield is commonly affected by factors that directly influence the health, nutrition, or harvesting of the tree, not by soil tillage practices.
Explanation:Pest infestation directly damages cocoa pods and lowers the quantity and quality of beans, so it reduces yield.
Fertiliser application supplies essential nutrients to the tree, which improves flowering and pod development, thus increasing yield.
The method of harvesting affects the care of pods and the tree, and careful harvesting protects future fruiting sites, so it does influence yield.
However, cocoa farms do not depend on regular soil tillage; the trees are deeply rooted and tillage is not a standard management practice for mature cocoa.
Therefore, the method of soil tillage does not significantly influence cocoa yield.
Answer:D. method of soil tillage