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Desertification: how it works

Photo credit: Science How stuff works

Beijing Image Gallery Workers in Beijing cover piles of sand before the 2008 Summer Olympic Games in an attempt to improve air quality. The sand blew in from desertified areas north and northwest China. See more pictures of Beijing.

China Photos/­Getty Images

How Desertification Works

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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

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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.

Read the full article: Science How Stuff works

Published by

Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.