oa Preliminary assessment of geochemistry and grain-size distribution of soils in Qatar

Soil plays an important role in life, especially in the cycling and supply of nutrients and water. Soil degradation is a serious global problem. It is caused by improper use of soil for different human activities. Soil degradation can lead to a significant decline in the productivity of agricultural lands. On a global scale, the annual loss of 75 billion tons of soil (mostly through desertification and soil erosion) costs the world about US$ 400 billion. Over 33% of the global land surface is affected by desertification, while only about 11% of global soil is considered to be stable. This study aims to perform a preliminary assessment of the soil quality at different locations in Qatar. Samples were collected from 14 sites at 8 different locations in the central east of Qatar, in May 2012. These locations are representative of a variety of desert soils (Umm Al-Zubar, Sealine, Semeisma, and Umm Al-Amad), farmland (Al Sailiya), a wastewater pond (Abu-Nakhala), a sandy beach (Katara Beach) and a protected area (Biological Field at Qatar University). The samples were analyzed using a Master Sizer 2000 particle size analyzer for grain-size analysis and by using ICP-MS for geochemical analysis. The results showed significant difference in soil texture (grain-size analysis) between all the study sites. Grain-size distribution analysis showed that soils at the Abu-Nakhala wastewater pond and the Katara Beach are composed almost exclusively of coarse particles (sand-size or higher), while area 3 of the QU Biological Field contained the highest amount of fine particles (over 52% of silt and clay). Geochemical analysis of the soil samples indicate that calcium is the dominant fraction in most of the samples, with concentrations varying between 61% and 89%. Magnesium is the second most abundant element (with concentration varying between 3% and 26%), followed closely by aluminum, with concentrations between 3% and 15%. Potassium (concentrations between 1% and 8%) and iron (1% to 6%) complete the list of major elements in the studied soils.