Learning from the past

There have been many examples in the last 2000 years of misuse of soils, even to the extent that it contributed to some civilisations coming to an end because they had damaged the soils they depended on so much that the soils could no longer sustain the population. Examples include civilisations in Mesopotamia in the Middle East and the Indus Valley in the current Pakistan. In both these cases the soils became so degraded through erosion and salinisation that they were no longer able to sustain the growing population. The rapid expansion in population in the past 200 years has placed extreme pressure on many of the world's soils. A major problem has been the increase in soil erosion, desertification, and salinisation mainly as a result of human activity and inappropriate land management. Six to seven million hectares are lost annually due to soil erosion. It is estimated that more than 20 million sq km is affected by soil erosion with at least 12 million sq km, an area larger than China, being damaged by the activities of man in just the last 50 years. The Food and Agriculture Organisation (FAO) has reported that at least 50 percent of the world's irrigated land now suffers from salinisation. The total irrigated land in the world is about 250 million hectares.

Desertification, resulting from a combination of climatic and human influences, now affects about one-sixth of the world's population and a quarter of the world's lands and reduces their productivity potential. Human activity is thus responsible for increasing damage to the soil that it will need to feed future generations This comes as a result of the pressure to grow food, the inadequate knowledge of the soils on which the food was being grown, or just sheer ignorance of the need to manage soils carefully. Erosion, desertification and salinisation continue to become more extensive, eating away at land that would be vitally important for food production in the future. Hence the scale of damage to the world soils is huge.

So it appears that we have not learnt from the experience of our ancestors and we are still continuing to degrade precious soils at an unacceptable rate, especially in the less developed parts of the world where the climate is more conducive to soil damage and poverty increases the pressure on the fragile natural resources.