Final answer:
Tropical soils have low fertility due to leaching of nutrients, lack of organic matter, and their thin nature.
Step-by-step explanation:
Tropical soils commonly have low fertility due to several factors. Firstly, high temperatures and high rainfall in tropical climates cause most of the nutrients in the soil to be leached out, leaving the soil deficient in essential nutrients. Secondly, the lack of winter dormancy in tropical areas prevents the accumulation of organic matter, resulting in soils with lower levels of organic nutrients. Finally, the thin nature of tropical soils further limits their fertility.