World Environment Day, 5 June

The United Nations’ World Environment Day main celebrations are to be held in Algeria this year with ‘Deserts and Desertification’ as the 2006 theme. Deserts, which now cover more than 40% of the planet’s surface, form an eco-system home to one-third of the world’s population. The 2006 slogan ‘Don’t Desert Drylands’ is based on these two important factors. It is predicted that global warming will increase the area of desert climates by 17% in the next century. Worldwide, desertification is making approximately 12 million hectares useless for cultivation every year. This is equal to 10% of the total
area of South Africa or 87% of the area of cultivated lands in our country.

Desertification is a process whereby productive land is turned into non-productive desert, mainly through poor land management. The process occurs in already semi-arid areas. Various factors cause desertification. These include overgrazing, cultivating lands on which there is high risk of crop failure, destruction of vegetation for use as fuel, poor management of land after accidental burning and incorrect irrigation practices causing build-up of salts in the soil. Increasing human population and poverty also contribute to desertification as poor people may be forced to overuse their environment in the short term.

Desertification is a self-reinforcing process. The reduction in plant cover that accompanies desertification leads to accelerated soil erosion. As vegetation and soil layer are reduced, water runs off the land instead of soaking into the soil. Then, as protective plant cover disappears, floods become more frequent. In South Africa approximately 300 - 400 million tonnes of topsoil are lost every year.

To halt desertification the number of animals on the land must be reduced, allowing plants to regrow. Soil conditions need to be improved by mulching and in some areas, reseeding may be necessary.

By Brenda Daniels