Arid soils of the Badia region of northeastern Jordan: Potential use for sustainable agriculture

摘要

Arid lands have always been important to the world's human populations, but their significance has increased over the past few decades because of population demographics and continued use of natural resources (Hoekstra & Shachak, 1999). Jordan is faced with increasing population pressure in its already settled areas; hence, it will have to utilize the underpopulated Badia, which forms 85% of Jordan's land surface, so that it can contribute to the economy in a sustainable way without damaging the fragile desert environments. This can be done by gaining a better understanding of the natural resource base and suggesting actions which will lead to the protection of the resources and to their sustainable usage for the long-term benefit of the local population. Azraq basin, about 12,750 km~2 in size, is located in the northeastern Jordanian Badia region (Shahbaz & Sunaa, 2000). To develop soil resources in the Azraq basin, research is needed to establish the best practices for their management, improvement, and maintenance. Four different areas in the Basin were investigated. The choice of these areas was based on geologic studies which showed the proximity of these areas to promising underground water resources. Most of the studied soils contain considerable amounts of carbonates. This leads to alkaline reaction of the soils with pH values mostly above 8, resulting in low availability of certain nutrients like phosphorus and micronutrients. If such soils are to be cultivated, proper management practices should be adopted to ensure the availability of those nutrients to crops. Analysis of the collected soil samples also showed that those soils contain soluble salts in the upper horizons in amounts enough to impede plant growth. Salts would have to beleached using good quality water before successful growing of crops can be carried out. Most of the studied soils have high erodibility and susceptibility to seal and crust formation. The soils in some of the studied areas contain high amounts of gypsumand carbonates and also very high content of soluble salts. Such areas would have to be excluded from any agricultural development. Reclaiming soils in such areas would be too expensive and not feasible economically. The use of organic amendments would be highly recommended to improve the physical and chemical characteristics of the Badia soils in order to achieve a sustainable agricultural production.