Comment: 18:18 - 19:20 (01:02)
Source: Annenberg/CPB Resources - Earth Revealed - 15. Weathering and Soils
Keywords: weathering, soil, tropic, jungle, "fertile soil", agriculture, "rain forest", vegetation, humus, nutrient, tree, plant, leaching, forest, erosion, wasteland
Our transcription: One region that has been adversely affected by this is the tropics.
Where the jungle floor would seem to be the most fertile environment possible.
Clearing the land for agriculture has, in many places, been a disastrous waste.
Because the floor of the rain forest is actually a rather unproductive soil.
Where, then, does all the luxuriant vegetation come from.
The fact is, the tropical rain forest creates its own nutrients in the form of humus, a thick layer of decaying trees and plants.
But because of the intense rainfall in the tropical jungles, nutrients in the soil are quickly leached and drained away.
So, when a forest is cut down, the humus is exposed to erosion.
The loss of this nutrient source ultimately results in a barren wasteland.
Geology School Keywords