This is the big one. Soils differ significantly between arid, temperate, and tropical climates. Basically it comes down to differences in the amount of rainwater, and differences in the amount of humus. If more rain, one also gets more plants, and potentially more humus. Dying plants can supply organic matter to the soil, which can turn into humus.
Lets build a table to look at the relationship between climate and soils.
This adds humus to the soil. And we have lots of rainwater. The rainwater becomes acidic by interacting with the organic matter and humus in the soil, and this acidic water promotes hydrolysis. This in turn increases the weathering rate, and results in thicker soils. B. Arid or semi-arid climates.