How can irrigation lead to desertification

As social and political forces intensify the pressures on the land that lead to desertification, land degradation itself can lead to further disruption of societal and political stability. The loss of fertile soil, water, and other resources, both for subsistence and for commercial use, leaves many people in dryland areas without the means to support themselves and their children.

These displaced populations often migrate to urban areas or to other countries, adding to population pressures and sometimes increasing the likelihood of social and political conflict. Resource Library. ArticleDetails Date February 1, Increasing population and improper irrigation techniques also contribute to desertification.

Desertification occurs in cropland both irrigated and nor irrigated , pasture, and woodlands. Loss of soil, deterioration of soil, and loss of natural vegetation lead to desertification. Drought, a period of unusually dry weather, can cause loss of vegetation, which in turn leads to desertification.

Poor land management and increasing population are factors that promote increased irrigation, improper cultivation or over cultivation, and increased numbers of livestock. These events alter the land and the soil, diminish the resources, and increase the chances of desertification.

Desertification has sometimes been mistakenly described as the expansion of deserts into nondesert areas. Pictures of sand dunes engulfing agricultural lands encourage this misconception, but this type of desertification is rare.

Arid and semiarid lands can be degraded even if there is no adjacent desert. Drought has also mistakenly been called the primary cause of desertification. Desertification can occur without drought, and drought can occur without resulting in desertification. Droughts are short-term and cyclical. By themselves, they do not degrade the land. However, they intensify the pressures that lead to mismanagement of land, plant, and water resources.

While dry land rainfall is low on average, it is extremely variable from year to year and from place to place.

Native plants and animals have adapted to this variability. Desertification indicators Soil salinity degree is evaluated by soil abstract analysis or by electric conductivity. Main criterion is salt concentration and ration of various ions. Trees density and their types changes.

It is necessary to consider vegetative formations consisting of different groups of green plants. Willyams distinguishes the following groups: Wood deciduous and coniferous vegetation Meadow grass vegetation. Steppe grass vegetation. Desert vegetation ephemeric.

Criteria are as follow: humus horizon thickness, nutrient elements concentration, pH, chemical composition, salinity. Monitoring methods Ground survey should be conducted twice a year spring and fall. Obtained information is interpreted for mapping purposes. Remote monitoring is satellite images use vegetation cover study and geo-botanic mapping. Mapping is one of methods to study soil cover and is basic information for agronomists, civil engineers and irrigators.

This mixture varied with time, place, and culture, since the harsh conditions forced people to be flexible in their use of the land. Population pressure, however, has led to the extension of cultivated lands in dryland areas. In some cases this has caused desertification and conflicts between herders and farmers who claimed access to the same land. In other cases, when policy and market conditions were favorable, it led to positive interactions between the two groups. In some areas, the increase in cultivation has been driven by increased irrigation which has often been unsustainable.

Irrigation can cause environmental problems such as waterlogging , salinization , water pollution, eutrophication , and excessive groundwater use. On the whole, irrigation has had a strong impact on inland waters , causing a decline in biodiversity and further desertification. Frequent and intensive fires can contribute to desertification when they affect natural vegetation. However, limited controlled fires can play an important role in the management of dryland herding and farming systems, promoting nutrient cycling and forage quality.

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