Geomatics Based Soil Mapping and Hazard Assessment of Cultivated Land in El-Fayoum Depression, Egypt.
Rafat Ramadan Ali, Soils and Water Use Dept, National Research Centre, Tahrir St., Dokki, Giza, Egypt and Fouad H. Soliman, Cairo Univ, El Gamaha st, Cairo, Egypt.
Geomatics were used in this study for producing physiographic and soil map of El-Fayoum Depression at small scale (1:250,000). Landsat ETM images (2001) and Digital Elevation Model (DEM) are used in ERDAS Imagine 8.4 software to produce the physiographic map of the studied area at the land form level. The obtained map shows that the area includes three landscapes, i.e., alluvial plain (851.55 km2), alluvial-lacustrine plain (543.30 km2) and lacustrine plain (194.20 km2). The terraces of various origin and elevation are the main land forms (64.99% of the total area); while the overflow and decantation basins represent 35.01 % of the area. The soils were classified to the sub-great group level on the basis of the key to soil taxonomy (USDA 2003), the correlation between the physiographic and taxonomic units were designed in order to produce the physiographic and soil map. The different soil units were represented by 16 soil profiles and 51 disturbed soil samples were collected and analyzed, and the obtained results were used for assessing the degradation hazard using (FAO 1979) guidelines. The obtained data show that the salinity, alkalinity and water logging are the main degradation type in El-Fayoum Depression, where the values of EC, ESP, and ground water level range between (1.2 – 36.22 dS/m) and (9.14 – 31.05 %) and (50 – 125 cm) respectively. The hazard of each type was defined in terms of low, moderate, high, and very high. The thematic layers of salinity, alkalinity, and water logging status were created in a digital format in Arc-View GIS 3.2 software and integrated together to produce the degradation status map. These results and maps will be a great base and sources help the planners and decision makers in proper planning.