عنوان مقاله [English]
Introduction: Geomorphology knowledge has an important role in knowing of the capabilities and environmental constraints of our surrounding, that in the meantime the use of the method of Land System Analysis is effective as a geomorphology approach. This method is a scientific classification based on the land form and with the hierarchical structure and emphasizes on the relationship of land (landforms) with the capabilities and constraints of land. In this study, the method of Land Systems Analysis is checked in Kalateh-Sadat watershed of Sabzevar of Razavi Khorasan province. The aim of this study is the use of geomorphology knowledg and the method of Land Systems in analyzing the capabilities and constraints areas, that it can be used in studies of territorial planning and management of natural resources.
Methodology: At first the studied area was limited based on topographic maps and Landsat satellite images of Google Earth software. Then from field observations, study books, articles and scientific reports in recent years on this topic and preparation of digital models of region with ArcGIS software was used. Finally, using the method of Land Systems Analysis was acted rather than classification of regions to ranges that have similar physical properties; So that each area is differentiated from another area by a specific homogeneity. The foundation of this classification is based on hierarchical structure that is summarized in three ranges land system, land unit and unit components.
Results and discussion: Kalateh-Sadat watershed is sub-basins of the Kal-shoor river of Sabzevar and is located in the central iran zone in terms of geological divisions and is considered from areas of ophiolitic-melange in iran. The most height of basin is in the northeast and the least in the output location in the southwest of the basin; in other words, topographic slope of basin is from the northeast to the southwest. Northeastern part of the basin (elevation points and upstream Kalateh-Sadat river) has high slope and the southwestern part of it (downstream and out of the river and agricultural lands) has least slope. Direction of dominant slope of the basin is southwest in other words, flow path of Kalateh-Sadat river to the output side. kalateh-sadat river is a dry-river and accidental river, which in addition passing through kalateh-sadat village, part of the downstream lands Irrigates and ultimately leads to holes central desert. Mostly regional precipitation is the effect of existence Siberian high-pressure mass in the cold season, that provides the grounds for coldness and dryness air. In terms of climate divisions based on Domarten factor, regional climate is dry type. This basin is also very poor in terms of vegetation and this poverty of vegetation has been happened during wrong operation of regional grasslands several years. In terms of land use situation, Kalateh-Sadat basin is parted into two parts medium grasslands and desirable and steppe grasslands with scattered trees. The most important of processes development of the earth current face in the kalateh-sadat basin include: orogenic phases and tectonic activity, the degradation processes and weathering, erosion system of flowing waters, mass motions and range, wind erosion system and human factors. kalateh-sadat village is located also on an alluvial fan and young terrace and low-height. The most common of geomorphology phenomenon in this basin is "Marly hills" of kalateh-sadat village and the impact of these marls on water and soil of the area, which from that is used for operations water-coloring and mud-lined the river bed. So that marl particles, with penetration on the floor of the river bed and downstream lands, fills pores available and creates a layer with low permeability ability and prevents water penetration in the floor of the river bed and lands and causes maintain water and soil in contrast to the heat and erosion and region winds. Finally, kalateh-Sadat basin from the viewpoint of land systems is divided into three types (system) mountain, hill and plain. That respectively, existence of chromite deposits, marly hills and maintain water and soil in contrast to erosion is in each at attention priority and importance.
Conclusion: At evaluation the studied watershed using the method of Land Systems Analysis was found that this range is an area with three different systems mountain, hill and plain that each is parted to land units and finally the smaller units component. Lowlands and low-height and plains with 52 square kilometers has occupied the most area of basin and land type of hill with an area of 11/2 square kilometers the least area. Land type of mountain is included also an area of 32/4 square kilometers of basin area. In general, the most area of Kalateh-Sadat watershed is covered lowlands and low-height. that the require more attention and efficient management of water and soil conservation is made clear in this region.