کاربست ویژگی‌های کانی‌شناسی اراضی بیابانی در کنترل کانون‌های بحران بیابانی قصرشیرین استان کرمانشاه

فرسایش بادی یکی از مهم‌ترین عوامل اصلی ایجاد کانون‌های گردوغبار در بسیاری از مناطق کشور است که در اثر تخریب اراضی و سوء مدیریت در بسیاری از مناطق ایران دیده می‌شود. بدین دلیل، هدف این تحقیق شناسایی شکل ناهمواری‌ها (مورفولوژی)، فعالیت، ویژگی‌های فیزیکی شیمیایی و مینرالوژیکی شنزارهای استان کرمانشاه است. در این مطالعه به‌منظور دستیابی به نتایج پژوهش، کانون‌های بحران در سطح استان کرمانشاه با استفاده از مطالعات میدانی و پرسشنامه‌ای شناسایی شد. سپس با نمونه‌برداری از نقاط بحرانی، ویژگی‌های فیزیکی و شیمیایی اراضی ماسه‌ای در مناطق بحرانی استخراج شد. نتایج نشان داد که مهم ترین شکل موجود در اراضی بیابانی منطقه موردمطالعه، پیکان ماسه‌ای و درجه فعالیت شنزارها، نیمه‌فعال و بیشتر آن‌ها تثبیت نشده است. منشا این ماسه‌ها از سازندهای آغاجاری است که در منطقه گسترش دارد و هرساله مقداری ماسه از آن‌ها هوا می بیند و جدا می شود، سپس توسط باد روی اراضی کشاورزی و مرتعی قرار می‌گیرد و بخشی هم حاصل رسوبات ماسه‌ای رودخانه‌های فصلی است. بررسی بینی‌کولر عناصر درخشان در بین نهشته‌های بادی قصرشیرین، از نقش موثر آبرفت‌های رودخانه‌ای و تپه‌های اطراف در تغذیه مناطق ماسه‌ای حکایت دارد. فعالیت‌های کشاورزی مانند عملیات آماده‌سازی بستر برای کاشت، سبب می شود این مواد فرسایش‌یافته به خاک اصلی اضافه شود و تغییر بافت خاک سطحی را به همراه دارد. بر اساس نتایج مطالعات آزمایشگاهی، نمونه‌ها عمدتاً فاقد گچ، ماسه‌ای و با  ph بین 7.18 تا 7.95 و مقدار ec بین 0.32 تا 3.18 میلی‌موس بر سانتی‌متر در نوسان است؛ بنابراین، پهنه‌های شناسایی‌شده جزء ماسه‌زارهای با اشکال پیکانی ماسه‌ای، غیرشور، نیمه ‌فعال و تثبیت نشده است. بررسی مورفوسکوپی نمونه‌ها نشان داد که بیشترین درصد نمونه‌های ماسه‌ای به شکل زاویه‌دار است که از فاصله نسبتاً کم بین محل برداشت و رسوب‌گذاری حکایت دارد. پیشنهاد می‌شود در راستای جلوگیری از تغییر بافت خاک و تخریب ساختمان آن، اقدامات حفاظتی (احیای پوشش گیاهی، احداث بادشکن زنده، مالچ پاشی و بهبود هوموس خاک) مناسب انجام شود.

investigating the role of mineralogical characteristics of desert lands in controlling desert crisis centers

1- introductionwind erosion is one of the main crises in arid and semi-arid areas’ lands with many destructive environmental consequences; this phenomenon has caused the transformation of natural environments and human living conditions in these areas. wind erosion causes the loss of soil and organic material, and consequently leads to its destruction (mahmoud abadi and rajabpour, 2017; dastrani et al., 2008), which is directly related to the physical and chemical properties of soil. soil texture and in particular the percentage of primary particles of clay, silt, and sand influence soil erodibility by affecting bulk density, aggregate stability, porosity, adhesion, shear strength, and threshold velocity. according to the study conducted by nagisi et al. (2016), the size and stability of soil aggregates are among the factors affecting wind erodibility. pasteur et al. (2016) also mentioned soil texture as a very important factor affecting soil and wind erodibility. according to the findings of kolazo and buchiazo (2010), sandy soils are inherently more erodible than fine-textured soils because due to the low amount of silt and clay in these soils, they cannot form physical ridges or aggregates. therefore, to control wind erosion, it is necessary to determine various environmental factors such as determining the direction and speed of erosive winds, determining the erosion threshold speed, and identifying the harvesting, transportation, and sedimentation areas in arid and desert areas as the effective factors in creating wind erosion and formation of desert lands. in desert areas, the amount of wind energy and its changes in different directions have a great impact on the morphology and deformation of wind erosion facies. therefore, one of the best methods to determine wind erosion is to use golbad (parsamehr et al., 2016). a review of the stabilization situation also provides local managers and politicians with broad perspectives on controlling this source of particular importance. therefore, the purpose of the present study is to identify crisis centers in creating wind erosion by examining the mineralogical characteristics of desert lands in kermanshah province, and finally, the research results will be used to control the identified crisis centers.2- methodologyin the present study, the potential of active sand dunes was identified by examining their physical and chemical properties, types of sand dunes, their active parts in susceptible parts of the study area, and the origin of active sand dunes identified for conducting management measures and desertification procedures. by conducting field visits and using irs satellite images, the range and shapes of sand roughness in the study area were extracted. after determining the range and shapes, criteria such as height, color, presence or absence of vegetation, and the shape of sand roughness, their active or inactive conditions were measured from different units of sand roughness that were separated in the previous step. physical, chemical, and mineralogical tests were taken and analyzed in the laboratory. then, by using granulation and granulometry results (measuring particle diameter), the abundance of sand minerals in the country was determined.3- results the results showed that the direction of the prevailing winds in qasr shirin meteorological station during the statistical period was generally south and then the prevailing wind was west, which, in addition to carrying quicksands, caused dust in these areas. in all the sands harvested in the study area, the acidity was between 7.5 and 8, which is in the alkaline range. salinity in all desert lands is less than 4 ds/m, which is in the group of non-saline soils. in the other quality parameters examined, all quality factors are in the normal range. according to the field observations, the studied areas are semi-active and unstable in terms of activity conditions. the sorting coefficient is 1.87 and the particle skewness coefficient is 0.11. therefore, its sorting is weak and its skewness is slightly symmetrical. in terms of shape, the grains are in the group of low-abrasive grains (low erosion). in this case, the grains are angular, but the corners are not sharp, indicating that destructive agents acted on the grain to a small extent. they also indicate that the distance between the harvesting area and sedimentation is short4- discussion & conclusionsby identifying areas prone to wind erosion and controlling these areas many of the environmental concerns can be alleviated. according to the obtained results, there are 7 sand distribution areas in kermanshah province, which are located in the west of the province and qasr shirin city, and often in the vicinity of iraq. the total area of ​​semi-active sand areas is estimated at 2333 hectares. according to the studies done, the sands of kermanshah province are scattered in the qasr shirin region in seven areas: 1- qasr shirin, 2- parviz khan, 3- ahmadi tower, 4- valedkoshteh, 5- naftshahr, 6- seyed sohrab, and 7- chaghamham. as mentioned, the most important shape is in the form of an arrow of sand, which is the result of the accumulation of sand behind plants and the unevenness of the ground. the primary origin of these sands is from aghajari formation spread in the region, which is first shaken by water erosion and then by the wind entering some sands into agricultural and rangeland lands every year. agricultural activities such as bed preparation for planting have increased wind erosion and the composition of the resulting sand has changed the texture of surface soil (jafari et al., 2009). the wind is an important and fundamental factor in creating sand roughness (kok et al., 2012). based on the results of laboratory studies on the collected samples, the ph of the sands fluctuates from 7.18 to 7.95 and the ec value varies between 0.32 and 3.18 mhos. the effect of electrical conductivity on wind erosion depends on the type and concentration of soluble cations. due to the small amount of organic carbon in the soils of arid and semi-arid regions, the presence of co3 as a source of non-aqueous carbon is of great importance in controlling the intensity of wind erosion (shahabi nejad, 2019). therefore, control erosion by creating vegetation in the upward areas will be possible when the identification of harvesting areas is prioritized in the implementation of quicksand stabilization plans (ahmadi et al, 2005). creating and strengthening vegetation is also effective in improving soil characteristics, which, as a result, improves the process of soil protection (mohseni et al, 2020).