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How Desertification Works
by Dave Roos
What Causes Desertification?
A balanced ecosystem is a healthy ecosystem. In a healthy dryland ecosystem, relatively few animals and humans attempt to survive on the limited resources of the land, which include water, fertile soil and trees. Since rainfall is infrequent in semiarid regions, the land is not built to support huge fields of crops or supply grazing land for hundreds of thousands of cattle.
The root cause of desertification is poor soil conservation leading to soil degradation. Healthy, productive soil is rich with organic matter called humus
. Humus is formed when decaying organic materials like dead plants and animals are transformed by micro-organisms and fungi into soil that’s rich in essential nutrients like carbon, nitrogen, phosphorous and sulfur
Unsustainable farming methods also contribute to soil degradation. Crop rotation, heavy composting and responsible use of chemical fertilizer ensure that the soil has enough organic imput to support vibrant micro-organisms. On the other hand, overuse of chemical fertilizers, failure to employ crop rotation and irresponsible irrigation practices rob the soil of the last of its nutrients. When topsoil is depleted of humus, it’s either too loose or too compacted, both of which can lead to destructive erosion.
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