پديد آورندگان :
فرج نيا، اصغر نويسنده مركز تحقيقات كشاورزي و منابع طبيعي آذربايجان شرقي Farajnia, A , ياراحمدي، جمشيد نويسنده استاديار مركز تحقيقات كشاورزي و منابع طبيعي آذربايجانشرقي ,
چكيده لاتين :
Introduction:
Soil studies are important and these studies are used as a basis studies in order to the exploitation of resources, including agricultural land, natural resources, and urban planning and environment investigations. As these study are complementary to the other soil related sciences, development of the comprehensive and homogeneous maps with a low cost is important. Geopodological methods could be facilitate soil studies and provides accurate picture of the soil distribution an area by reasonable cost (Rossiter, 2000). Above mentioned method initiative organized by the Netherlands Institute of Informational (ITC) has become the global credit. In the hierarchical structure of this method, structure of the earth, poured into generation, lithology, land terrain view and landform as an accuracy level are considered. In this method the location of soils on slopes that have main role on the chemical properties, soil fertility and management of them, therefore are considered as important effective factor in the soil unit separation. Also in this method the combined effect of phonologic process and morphology that are effective on the soils formation, distribution, mapping and classification, productivity and management of them, in mapping unite separation and increase their purity through phonologic process analysis is much important (Alfred Zing, 2013). Important factor that will be considered in the preparation of the soil map, is variation within and among administrative units of the soil map. If the amount of variation within the map units is greater than the variability among units, the purity of the units are increased. The main objective of this study was to use Geopedology method to development of Harzand plain soil map in northwestern East Azerbaijan Province and comparison it with the previously map that has been prepared by Physiographic method.
Methodology:
This study were conducted using basic maps of the study area including topography 1:25000, geological map (Geological Survey 1: 10000), aerial photographs 1: 20000 (Armed Forces Geographical Organization, 1968) and the image of Landsat ETM by application of GIS and Remote Sensing. After development of the acquired maps (DEM, slope aspect and percentage, lithology and three-dimensional image of the study area) and analyses of them, soil sample area was selected. Soil sample area was chosen based on that at least one observation point (profiles) was drilled in each map unit. In order to increasing the sampling accuracy, the outsides area from observation point was analyzed to investigation of differences between sampling point and total of the each units. If a new unit is showed that have difference structure from observation point, new soil profile has excavated and characterization of the soil were studied. Drilled profiles have described and soil samples from different layers were prepared and transformed to the laboratory. Soil profile description and morphological studies were conducted using Soil and Water Research Institute Conventional Method By analyzing of the soil samples experimental results and morphological studies, the soils are classified based on comprehensive 19 soils method, various landforms were detected and named. Results derived from soils classification in various landforms was extended to the other similar landforms of the study area. After preparing of the soil maps by Geopoedology method, accurately of this method were compared with the soil map that has been prepared by physiographic method (common in Iran).
Results and Discussion:
Results showed that this research study area was formed of three geomorphologic units including Mountains, Plains and Valleys. The mountain units with 54 percent of the land, is steeped, has been segregated into four subunits. Very shallow soil with rocky surface are dominates, in the physiographic method represented by the singe of Tand without any work done on it, has been removed.45 percent of the remained area with a slope below 10 percent belong to the piedmont plain that most of the farming and gardening land are located on this unit. Levels that downed on the plains in landform surface were called low land. The third separation unit is the valley that according to the valley definition, area that extends between the low and long, were called. Valley is drained by rivers and discharged. This unit covers the 660.5 acres of the area and as the same as previous soil map, has determined, represented by the singe of R.W and finally has been removed.
Conclusion:
This study were conducted in order to development of Harzandat plain soil map in northwestern Est. Azerbaijani Province and comparison it with the previously map that has prepared by Physiographic method. In the geopodology method 8 soil families were detected in two orders of the Entices and Inceptisols, 69 land units and 145 land boundaries. These results in compression with the physiographic method that 37 map unit and 63 boundaries map have been detected, have high quality. Also in this method only 37 soil sampling profile were drilled that in compression with physiographic method (180 profile), less time and cost needed to preparing a soil map. In physiographic method systematic analyses of the landscape and geomorphological level decomposition don’t be done and the role of the geomorphologic unit, the location of these units on slope and phonologic process don’t be investigation. In addition, the determination of the composition of the soil map units is not considered, determination of unit boundary and map boundaries are based on trial and error and free from statistical aspects. All of the abovmantioned reason showed that the geopodology method have high accuracy from physiographic method in order to soil map development.
