Semi-Detailed Soil Mapping of Selected Areas in Lemnos Island
By Agricultural University of Athens
Soil surveys describe soil characteristics in specific areas, classify the soils of these areas based on internationally recognized classification systems, delineate the boundaries of soils with similar properties on the map, and predict their behavior according to the purpose for which mapping is
performed. Soil properties vary from land to land and this differentiation is not at all accidental. Soil is the result of the influence of climate and living organisms on the parent material, while the topographic relief exerts a significant influence on its evolution and time is necessary for its formation processes.
Parent materials contribute to the diversification of soils within the limits of climatic zones and vegetation zones. The local peculiarities of topography add extra complexity as they affect the time of soil exposure to soil formation processes and the types of these processes. Complex interactions between the abovementioned factors appear in repeated geomorphological patterns and therefore, every distinct geomorphological pattern may contain one or more soils. This is precisely the basis for the identification, and mapping of soils in the field. Soil surveys are carried out at different levels of detail depending on the specific needs they serve. According to the rules of cartography, the greater the detail required in mapping soil differentiations, the greater the scale of the map being created.
Soil Mapping Units (SMUs) group soils with similar physical and chemical properties and are designed to transfer important information about the most appropriate use of soils in the study area. SMUs must in principle be readily identifiable and mapable on scales compatible with the available mapping backgrounds. The main differences between soil surveys of different scales relate to the nature of SMUs, the frequency of on-site observations and sampling, and the accuracy of the SMUs limits. The choice of the detail for the soil survey depends on the purpose for which it is carried out, but in fact the final choice is also determined by other factors related to the scale of the available mapping backgrounds (geological maps, ortho-photo-maps etc.) and of course to its cost. When there is interest in carrying out a soil study designed to facilitate local planning issues and to respond to the sustainability issues of the actions attempted, the most appropriate level of detail is the semidetailed mapping of soils (1: 20.000 – 1: 50.000). In these cases, the minimum area (1 cm2 ) that is distinct with the naked eye on the printed soil map varies from 6-36 hectares (Zinck, 1995).
In the context of the Terra Lemnia project a semi-detailed soil survey was carried out in the four study areas of Lemnos (Vigla, Fakos, Ifestia, Fisini) to characterize the main soil physical characteristics, such as drainage, soil texture, parent material, slope gradient, soil depth, presence of inorganic carbonates, limiting layers, soil taxonomic unit, etc. In addition, soil sampling was carried out in the 25 Sampling Areas (SAs) of the project and laboratory analyses were undertaken for more detailed characterization of soils. The accuracy of the soil survey corresponds to a scale of 1: 30.000.