Major Causes of Land Degradation and Desertification in Jordan.
Sa'eb Khresat, Jordan Univ of Science and Technology, Irbid, Jordan, Jordan
The existing ecosystems in Jordan are fragile and prone to deterioration. This resulted in lower vegetative cover and eventually the loss of the fertile topsoil. This made the soil incapable of supporting plant growth and made it more susceptible to degradation. Desertifcation is intense in the steppe zone, which serves as the desert forefront. Investigations showed that climate in this zone had changed several times during the Quaternary. The last of these changes was the present aridic climate. The last episode of climatic changes is responsible for the development of unfavorable soil properties that accelerated the degradation of many plant species. Coupled with the effect of continuing drought incident, the removal of plant cover was greatly enhanced. The purpose of this study was to discuss the major causes of land degradation and desertification in Jordan. Sites that receive different amounts of annual precipitation and different vegetation types were selected to represent the major agricultural areas in Jordan. The climate of the study area is of Mediterranean type with an average annual precipitation ranging between 200 and 500 mm The major soil properties that can be linked to land degradation were studied.The leading causes of land degradation in Jordan are improper farming practices (such as failure to use contour plowing, or overcultivating the land), overgrazing, the conversion of rangelands to croplands in the marginal areas, where rainfall is not enough to support cropping in the long term, and uncontrolled expansion of urban and rural settlement at the cost of cultivable land. Implementation of soil conservation and erosion control measures such as contour plowing, terracing, and stonewalls construction on farmer's fields helped in curbing accelerated erosion and in protecting the potential agricultural lands. Keywords: Land degradation, Desertification, soil erosion, arid climate, Jordan.