Mohsen Asadollahi; Mohammad Jafari; vahid sayare; Ali esmaeili; Mohammad Tahmoures
Abstract
Wind erosion is one of the most important aspects of land degradation in arid and semi-arid regions, which 20% of land area of the world has been influenced by wind erosion. The wind increases the desertification process by displacing sand dunes. Therefore, the stabilizition and preventing the moving ...
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Wind erosion is one of the most important aspects of land degradation in arid and semi-arid regions, which 20% of land area of the world has been influenced by wind erosion. The wind increases the desertification process by displacing sand dunes. Therefore, the stabilizition and preventing the moving sands is essential. A strategy to combat this phenomenon is to reduce wind speed or to increase surface cover and soil resistance against erosion winds. The application of mulch or soil cover is one of the methods widely used to stabilize moving sands. For this purpose, a study was done at the Research Station International Desert Research Centre in Kashan city. The main purpose of this study was to investigate the effect of Multivariate biopolymer treatment at three concentrations (15%, 30% and 60%) on the moisture content of three sand depths (first depth of 0-5 cm, second depth of 5-10 cm and depth of third 10-20 cm), and study this mulch Compared with levels without mulch on the sand. Results showed soil moisture retention in Mulching compared to the control treatment, and statistically, there was significant differences between different depths of soil moisture Mulching compared to the control treatment and in between the first, second and third depths, the first depth had the highest increase in moisture holding compared to the Control treatment.
Salman Zare; Mohammad Jafari; Hassan Ahmadi; Hasan Rouhipour; Reza Khalil Arjomandi
Abstract
In this regard, the present study aimed to evaluate the performance of some of the non-oil mulch to stabilize sand dunes in the Kashan's Rig-boland desert. monthly surveys are conducted in the desert areas. To evaluate the effect of mulch on stabilizing the sand dunes, the effect stabilization index ...
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In this regard, the present study aimed to evaluate the performance of some of the non-oil mulch to stabilize sand dunes in the Kashan's Rig-boland desert. monthly surveys are conducted in the desert areas. To evaluate the effect of mulch on stabilizing the sand dunes, the effect stabilization index was used. The results indicate there is a significant difference between different mulch. The comparison test showed that the highest coefficient effect of stabilization with significant effect done on the biological mulch. After that, however, three other mulches including resins, inorganic and polymer are, respectively had the most significant effectiveness. Although there was not significant difference between these three types of mulches. Biopolymer Mulch with the lowest coefficient of stabilization effect showed significantly different from other mulches. Mulching in the hills with biological mulch, due to tightly crust formation against erosion, removal of sand and dunes almost stopped and hill completely has been stabilized. In this study, used mulches were initially very resistant and feasting the sands dune surface such as resistance crusts which were loss against any tensile and compressive force before mulching practices. . Therefore, different mulches treatments according to their durability and nature of structural have different effectiveness in reducing wind erosion effect. Among the studied mulches, just biological mulch and has usability and is capable for executive pilots.
hossein mohammad asgari; shahram khalighi sigarodi; Parviz Irannejad; Hassan Ahmadi; Arash Malekian
Abstract
Aerosol impact on people health, social and economic activities, land and water ecosystems and meteorological parameter. The GOCART scheme was evaluated for simulating PM10 in this study. GOCART was run into WRF model as a host model. Reanalysis data from FNL for every 6 hour was used for initial conditions. ...
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Aerosol impact on people health, social and economic activities, land and water ecosystems and meteorological parameter. The GOCART scheme was evaluated for simulating PM10 in this study. GOCART was run into WRF model as a host model. Reanalysis data from FNL for every 6 hour was used for initial conditions. One domain and two nests were used to cover region from West Africa till East Asia, Iran and Khuzestan Province. Primary results shown that the model overestimate surface moisture and the results was weak for simulating PM10 ,so we modified surface moisture using welting point of soil texture in desert region for summer. In addition, erodibility index was defined using surface moisture and threshold wind velocity and coefficient of this index modified using Tir and Day PM10 data at 1387. Results of modified model were compared with observed data in environmental station in Ahwaz for one week from 25, 3,1388 till 31,3,1388. Statistical analyses shown that, GOCART has a good capability for simulating PM10.
Mohammad Reza Ekhtesasi; Fateme Hazirei
Abstract
Mulching is one of the methods of sand movement control to prepare condition for permanent fixation. Oil mulches have been used in Iran. Because of high cost and negative environmental impacts of oil mulches, changes in mulches type and mulching methods is vital. Therefore, for the first time in Iran, ...
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Mulching is one of the methods of sand movement control to prepare condition for permanent fixation. Oil mulches have been used in Iran. Because of high cost and negative environmental impacts of oil mulches, changes in mulches type and mulching methods is vital. Therefore, for the first time in Iran, different combinations of cement and lime were examined as stabilizer. Sandy soil from the Yazd-Ardakan plain is used as bed treatment and Portland cement were used as the mulch in this research. The treatments were prepared using different ratios of the above mentioned materials. One liter of water was added to each mulch combinations and were sprinkled on the plot of 100 cm (length) × 30 cm (width) ×4 cm (height) sands. A completely randomized design is used as research plan with three repeating. Physical parameters, such as thickness, compressive strength, which are created by mulches, and wind erodibility of the treatments were measured. The measured data were analyzed using SPSS statistical software. Results show that by increasing the amount of cement, soil crust resistance increases. The combination mulch of cement 400 gr, sand 800 gr, and lime 10 gr is selected as the best treatment, because it can be prepare optimum physical conditions for sand dune fixation. In addition, the cost of field cement mulching estimated 30% lower than oil mulching.
Behzad Rayegani; Gholamreza Zehtabian; Hossein Azarnivand; seyed kazem alavipanah; Sayed Jamaleddin Khajeddin
Abstract
Soil is one of the main non-renewable natural resources in the world and its degradation is considered as a major threat around the globe because it reduces the productivity capacity of soil variability and makes the environment instable in the long turn. Soil degradation has three different ...
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Soil is one of the main non-renewable natural resources in the world and its degradation is considered as a major threat around the globe because it reduces the productivity capacity of soil variability and makes the environment instable in the long turn. Soil degradation has three different aspects: Physical, Chemical and Biological degradation. If any of these aspects of the destruction of the soil can be estimated in an equation, assessment and estimation of the soil degradation can be done easily. To achieve this goal extensive efforts have been made in various parts of the world and different methods for assessing soil degradation have been suggested. In this research latest guideline of soil degradation assessment presented by Land Degradation Assessment in Aridlands is used to desert region of the east of Esfahan and different aspects of soil degradation is assessed by that. According to the findings of this research, LADA methodology of soil degradation easily can be used by most users within the country because the method is simple and provides results as fast as possible. Comparing the results of this method and photos of relative the sampling sites has shown the model is reasonably accurate.
Asghar Tavakkoli Fard; Aliakbar Nazari Samani; Naser Mashhadi; Hoda Ghasemieh; Mojtaba Hodayi Arani
Abstract
Kashan Erg is one of the most important sand dunes complexes in Iran. It is included the most important various type of sand dunes in Iran. This study was performed to compare the granulometry of aeolian sediments in different sand dunes and also from plinth to crest of transverse dunes that located ...
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Kashan Erg is one of the most important sand dunes complexes in Iran. It is included the most important various type of sand dunes in Iran. This study was performed to compare the granulometry of aeolian sediments in different sand dunes and also from plinth to crest of transverse dunes that located in Kashan Erg’s north. In order to determining different statistical variables, aeolian sediment sampling was conducted in different sand dunes. Then, the sample’s granulometry test was done based on dry sieve analysis. Finally, statistical parameters such as mean diameter, Sorting, Skewness, Kurtosis, d10, and d90 were determined. The results showed that the mean diameter, Sorting, d10 and d90 parameters have significant differences at the 95% significance level between the stabilized sand dunes and active ones. Moreover, it was found that in transverse sand dunes, there are a significant difference at the 95% significance level between mean diameter and d90 parameters in bottom of the stoss side and lee side.
Tayyebeh Mresbahzadeh; Hasan Ahmadi; GHolamreza Zehtabian; Fereydun Sarmadian; Firoozeh Moghiminejad
Abstract
Desertification is specific phenomenon of arid, semi-arid, dry sub humid regions. This phenomenon has a high rate in developing countries such as Iran. The main objective of this research was calibration of IMDPA model in Abuzeidabad (Kashan) region with emphasis on land criteria. IMDPA model, introduced ...
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Desertification is specific phenomenon of arid, semi-arid, dry sub humid regions. This phenomenon has a high rate in developing countries such as Iran. The main objective of this research was calibration of IMDPA model in Abuzeidabad (Kashan) region with emphasis on land criteria. IMDPA model, introduced by Iranian researchers to assess desertification intensity in Iran. Before application, the criteria and indices applied in model were re-defined For this study. Regarding to region conditions three criteria were defined as key criteria for desertification which were: Geology-geomorphology, soil and wind erosion criteria. Then each criterion was assessed based on selected criteria, which resulted in qualitative mapping of each criterion based on selected criteria. Finally, by mean of all the indices and criteria desertification mapping was provided and these results obtained. Regarding the studied criteria, Geology– Geomorphology benchmark has the highest effect on desertification. Among the total studying are (16161 hectars), the medium class is about (4792 hectars), and the high class is about (11369 hectars). Among indicators, slop index with 3.9 and lithology sensitivity to erosion and wind erosion with the value of 3.5 and 3.4 are the main indexes of increase in desertification intensity in the study area. According to map of desertification statue 70.3% of study area have a high intensity and 29.7% have a medium intensity.
M. Akbarian; S. H. Kaboli; N. Moradi
Abstract
Determining the relative sensitivity of land to erosion and its factors, could be the basis of soil conservation programs. The aim of this study is to compare water and wind erosion functions in land degradation of Dasht-e-Jeihoon using PSIAC and IRIFR.EA models and the source studying of aeolian sediments ...
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Determining the relative sensitivity of land to erosion and its factors, could be the basis of soil conservation programs. The aim of this study is to compare water and wind erosion functions in land degradation of Dasht-e-Jeihoon using PSIAC and IRIFR.EA models and the source studying of aeolian sediments in geomorphologic facieses as homogeneous units. The results indicate that in Dasht-e-Jeihoon, water erosion has been transferred fine and coarse grained sediments to the center of plain. In fact, in this region wind erosion fulfills the effect of water erosion in center of the plain. Erosion estimation shows that 50.3 percent of the region includes the mountain facieses )erosional or bare pediment (which water erosion is moderate to high, have minute to low wind erosion and 49.7 percent of the region includes the facieses of Epandage and covered pediment which water erosion is low while wind erosion has moderate to high effects. Water erosion not only results 39.7 percent of the Dashte-Jeihoon sedimentation, but also it has a significant role to supply erodible particles in downstream of the region. Observations and the results showed that for estimating the erosion in dry areas such as Dashte-Jeihoon, we need to use water and wind erosion estimator models as supplements.
Tayyebeh Mesbahzadeh; Hassan Ahmadi
Abstract
Sand dunes mobility is one of the serious problems in arid regions. Since wind regime is one of the important factors in sand dunes formation, its frequency, direction and magnitude can be effective. Amount of wind energy and its directional variability (wind regime) have significant control on the morphology ...
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Sand dunes mobility is one of the serious problems in arid regions. Since wind regime is one of the important factors in sand dunes formation, its frequency, direction and magnitude can be effective. Amount of wind energy and its directional variability (wind regime) have significant control on the morphology and maintenance of aeolian landforms. By recognizing of morphometric and morphodynamic characteristics, it is possible to control soil erosion. Thus, statistical analysis of wind data using Tsoar index (sand dunes mobility index) in the study area was considered to understand wind regime role in volume and direction of transported sediments. Sand drift potential amount of the study area is 100.8 v.u. and sand flux is 2.358 m3/m.year resulted from Lettau – Lettau equation. Considering wind erosion power, the study area is in low class based on Fryberger & Dyne (1979) classification. In spring the wind blowing pattern has west direction and is different from other seasons. Also, the most frequency of blowing wind higher than threshold velocity occurs in this season. Unidirectional index value is 0.64 for this region that results formation of transverse dunes (barkhanoid).
s.m Hoseini; M.R Ekhtesasi; A.R Shahriyari; H Shafiei
Volume 63, Issue 2 , September 2010, , Pages 165-18
Abstract
Sistan plain is affected by desertification and this phenomenon has serious impacts on roads and socio- economic activities of local people of this region. The main purpose of this study is estimating the current and potential desertification intensity of Niatak region of Sistan based on MICD method. ...
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Sistan plain is affected by desertification and this phenomenon has serious impacts on roads and socio- economic activities of local people of this region. The main purpose of this study is estimating the current and potential desertification intensity of Niatak region of Sistan based on MICD method. That, through it the working units of this region were prepared as the base map for evaluating to consider the factors and indices by geomorphology method. Also, in order to prepare the desertification intensity condition for both current and potential situations of this region, the desertification intensity of various applications was determined and relative plans to current and potential desertification of each land use were prepared after evaluating wind erosion indices and accumulating their scores for each working unit based on reference tables. The results showed that in this region the desertification potential consists of medium (III), intensive (IV) and very intensive (V) classes, while current desertification condition includes low (II), medium (III) and intensive (IV) classes of desertification intensity, respectively. These variations were resulted by wind erosion control activities over recent years.
