The objective of this study is to generate thematic geodatabase information on soil resources of UAE. The soil map of Dubai and Hatta was prepared at 1: 25,000 scale using the Indian Remote sensing Satellite (IRS-ID) Linear Imaging Self Scanning Sensor (LISS IV) data. The soils of the study area were classified as per USDA (2003) up to soil series and their association level. STUDY AREA The project area covers the UAE, an area of 4000 sq km (Figure1). The overall climate of the Emirates is subtropical, warm and arid. Air temperatures range between 350 to 500 C from May to October during the middle of the day and between 200 to 350 at mid-day during the winter months. The average annual rainfall of the Emirate which falls mostly during winter months is about 100 mm. The rainfall, however, is very erratic and varies extremely both from year to year and place to place. Some moisture also condenses in the form of fog and dew, especially in the coastal belts. Strong winds and sand storms are also of common occurrence throughout the Emirate. They are especially more frequent and severe during summer months. Sand dunes are the dominant feature of the landscape over most of the Emirate. INPUT DATA In the present study for generating base line information on soil resources of Dubai and Hatta area the Indian Remote sensing Satellite (IRS-ID) Linear Imaging Self Scanning Sensor (LISS-III & LISS IV) data have been used. Ortho-rectified IKONOS data is provided by Dubai Municipality for Geo-referencing of IRS - P6, LISS IV data Besides the satellite data the base maps prepared by the project team, published soil maps, topographic maps, climatic data etc. are also collected and used as collateral data. METHODOLOGY Essentially soil survey is a study and mapping of soils in the field. It is the systematic examination, description, classification and mapping of soils of an area and it comprises of a group of interlinked operations involving
The over all methodology for mapping the soils is shown in Figure 3.  Fig. 1 Study Area Preliminary visual Interpretation The steps involved in pre-field interpretation is monoscopic visual interpretation of Indian Remote Sensing Satellite (IRS) ID LISS-III and IRS P6 LISS IV data at 1: 25,000 scale based on the standard remote sensing techniques using image characteristics such as tone, texture, pattern, shape, size, association etc. in conjunction with the collateral information available in the form of published maps and reports. A tentative interpretation key in terms of lithology, physiography, land use/land cover, erosion/salinity/ alkalinity hazards and image elements was developed. Field work A field visit was undertaken in Dubai and Hatta study areas, to study important characteristics of soils and associated land features for mapping soils. The first step in soil survey begins with general fact finding exercise through a reconnaissance of the area, so a preliminary study on the landform, geology, climate and vegetation of the study area was undertaken. For carrying out the fieldwork the scientists traversed the study area with a base map, satellite imagery for the first three days. During the traverse, the scientists noted the variations in landforms and associated soils. The ground features were also correlated with the image features. Soil profile studies and sample collection The detailed soil-site study was undertaken in each soil-mapping unit by general traversing and by collecting surface soil, minipit and soil profile observations at intervals depending on soil variability. The soil profiles/pedons (A vertical cut from the surface down to the hard rock from which the soil is formed gives the soil profile and in the profile several successive characteristic layers can be identified. A profile pit with exposed vertical face of approximately 1 meter across to an appropriate depth (nearly 1 m) was satisfactory for most soils. Each layer (horizons) was studied for various morphological features such as colour, texture, structure, consistency etc. The frequent profile sampling enabled to determine the depth of various horizons and also the horizons of gains (alluvial) and losses (eluvial). Sometimes, by merely looking at the surface soil and at other times, by rubbing the surface soil between thumb and fingers (to determine soil texture) reflects soil properties. A detailed description of each profile was noted down on the pro-forma. The pro-forma includes many parameters, which were collected. This includes, Location of the soil profile in terms of latitude and longitude, Physiographic unit, Parent material / Geology, Slope (%),Soil characteristics, Soil depth, Soil texture, Consistency and much more. Also Effervescence test was performed by squirting 10% HCl on the soil to determine the free carbonates. In Dubai and Hatta area 129 soil profiles were excavated and large number of observations were also taken. In total 333 soil samples were collected. |