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Issue Info: 
  • Year: 

    2016
  • Volume: 

    -
  • Issue: 

    76
  • Pages: 

    16-25
Measures: 
  • Citations: 

    0
  • Views: 

    253
  • Downloads: 

    0
Abstract: 

In this study,corrosion of AISI st37 steel waste casks was investigated by analyzing the physico-chemical characteristics of the soil medium.The chemical composition of soil has important effects on steel casks.Moisture,soil electrical resistivity,soluble salts,chlorides,pH,redox potential and anions and cations content,as the major parameters,influence the exterior corrosion of waste casks.To carry out this research,the corrosivity of the soil in the central desert regions of Iran has been studied using the AWWA C105 standard.In these regions,4 samples have been collected at varied points located in the vicinity of the site,named CR1,CR2,CR3 and CR4.At first,for a better assessment of the soils corrosivity,the physical and chemical analyses were conducted on the soil and in the solutions prepared from the soil samples.Then,the rate of corrosion was measured by the weight loss and potentiodynamic polarization methods.The obtained results showed that the CR4 soil sample with the lowest electrical conductivity,compared with the other samples,has the lower corrosion rate in the whole method.Corrosion rates of the samples in this region in the 180-day weight loss method,and in the electrochemical method are equal to 0.0625 and 0.029 mm/y,respectively.

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Issue Info: 
  • Year: 

    2023
  • Volume: 

    9
  • Issue: 

    1.2
  • Pages: 

    52-79
Measures: 
  • Citations: 

    0
  • Views: 

    72
  • Downloads: 

    9
Abstract: 

Burial of urban waste is one of the main problems of the current century. To the extent that it has affected the vital resources of human life. Langrod City in Gilan province, like any other city in the world, is involved in the problem of urban waste. Failure to set up the compost plant of this city in the Atakor region has caused a huge amount of waste to be stored and the infiltration of toxic leachate for more than a decade and many problems for the residents. The purpose of this study is to investigate the pollution status of Quaternary soils in the region. The method of this study is based on eight pollution indices including land accumulation index (Igeo), enrichment factor (Ef), modified pollution degree (mCd), pollution factor (CF), pollution load index (PLI), toxic risk index (TRI). , modified hazard quotient (mHQ) and potential environmental risk (RI). The results show that the quaternary soils of the region are contaminated with heavy metals. Both earth-born and man-born factors have played a major role in these pollutions. Erosion of metamorphic units is the main factor in the accumulation of some heavy metals in the form of ground deposits. The location of the waste depot can be considered the only man-made factor of pollution in the region. It should be noted that, except for the two metals lead and zinc, the contribution of man-made pollution is much lower than the earth-made factor. Setting up a compost factory and building a sewage drainage network can have a significant impact on reducing the rate of pollution.Burial of urban waste is one of the main problems of the current century. To the extent that it has affected the vital resources of human life. Langrod city in Gilan province, like any other city in the world, is involved in the problem of urban waste. Failure to set up the compost plant of this city in the Atakor region has caused a huge amount of waste to be stored and the infiltration of toxic leachate for more than a decade and many problems for the residents. The purpose of this study is to investigate the pollution status of Quaternary soils in the region. The method of this study is based on eight pollution indices including land accumulation index (Igeo), enrichment factor (Ef), modified pollution degree (mCd), pollution factor (CF), pollution load index (PLI), toxic risk index (TRI). , modified hazard quotient (mHQ) and potential environmental risk (RI). The results show that the quaternary soils of the region are contaminated with heavy metals. Both earth-born and man-born factors have played a major role in these pollutions. Erosion of metamorphic units is the main factor in the accumulation of some heavy metals in the form of ground deposits. The location of the waste depot can be considered as the only man-made factor of pollution in the region. It should be noted that, except for the two metals lead and zinc, the contribution of man-made pollution is much lower than the earth-made factor. Setting up a compost factory and building a sewage drainage network can have a significant impact on reducing the rate of pollution.Burial of urban waste is one of the main problems of the current century. To the extent that it has affected the vital resources of human life. Langrod city in Gilan province, like any other city in the world, is involved in the problem of urban waste. Failure to set up the compost plant of this city in the Atakor region has caused a huge amount of waste to be stored and the infiltration of toxic leachate for more than a decade and many problems for the residents. The purpose of this study is to investigate the pollution status of Quaternary soils in the region. The method of this study is based on eight pollution indices including land accumulation index (Igeo), enrichment factor (Ef), modified pollution degree (mCd), pollution factor (CF), pollution load index (PLI), toxic risk index (TRI). , modified hazard quotient (mHQ) and potential environmental risk (RI). The results show that the quaternary soils of the region are contaminated with heavy metals. Both earth-born and man-born factors have played a major role in these pollutions. Erosion of metamorphic units is the main factor in the accumulation of some heavy metals in the form of ground deposits. The location of the waste depot can be considered as the only man-made factor of pollution in the region. It should be noted that, except for the two metals lead and zinc, the contribution of man-made pollution is much lower than the earth-made factor. Setting up a compost factory and building a sewage drainage network can have a significant impact on reducing the rate of pollution.

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Issue Info: 
  • Year: 

    2019
  • Volume: 

    33
  • Issue: 

    2
  • Pages: 

    221-230
Measures: 
  • Citations: 

    0
  • Views: 

    397
  • Downloads: 

    0
Abstract: 

Introduction: Cyerus rotundus is a perennial weed of the Cyperaceae family spread throughout the tropical and subtropical parts of the world. It is a C4 and fast-growing plant that replicates rapidly through the extensive underground system and tuber. This weed causes damage to more than 92 countries and 50 crop species. In this regard, it is considered as the most damaging weed in the world. The amount of damage varies depending on the crop. One of the most important characteristics of purple nutsedge is the production of the tuber. According to available studies, burial depth of tuber plays an important role in the emergence of the onset of the competition period. Among the physical properties of the soil, soil texture plays an important role on plant growth characteristics, development of underground organs, especially in tuber plants and the amount of water penetration and maintenance. So, given the importance of accurately recognizing the biology and the ability to reproduce of nutsedge in its management, this research is also intended to study the effect of burial depths and the soil texture on the growth of purple nutsedge. Materials and Methods: In order to evaluate the effects of soil texture and burial depth on purple nutsedge vegetative characteristics, a trial was conducted at Kerman Natural Resources and Agricultural Research Center, using factorial statistical method and experimental design of randomized complete blocks at three replications. The first factor was burial depth at five levels (2, 12, 22, 32 and 42 cm) and second factor was soil texture at three levels (sandy loam, silty loam and clay loam). The traits of emergence percentage, the time of emergence, the number of produced tubers and dry weight of the underground organs were measured at 130 days after planting. For this purpose, the pots and dumps were emptied, then the underground organs were separated and placed in paper envelopes and finally, paper envelopes were placed in oven with temperature of 75° C for 72 hours. Data were analyzed using SAS v. 9. 1 software. Figures are also plotted by Sigmaplot v. 12 and Excel v. 2013. Results and Discussion: The results showed that emergence time, germination percentage, underground organ dry weight and tuber numbers were affected by depth of planting and soil texture. Emergence of C. rotundus was faster in sandy soil and at a lower depth, so that the tubers grew in the sandy loam soil at a depth of 2 cm 7/7 days after planting (the shortest time), and silty loam and clay loam were ranked next lowest. Understanding ecology of germination and weed emergence plays an important role in their management. With increasing depth of sowing, the percentage of germination in the tested soil texture decreased. So that the maximum amount of germination (85%) was obtained at 2 cm depth of sandy loam soil and the lowest germination percentage was observed at depths > 32 cm in silty loam and clay loam soils and the depth of 42 cm of sandy loam soil encountered with no germination and emergence of seedling. According to the results, the underground organ dry weight of C. rotundus in the textures and depths of the soil was quite different. In sandy loam, the highest underground dry weight was obtained at the 2 cm depth and the lowest was at 42 cm depth (0) of sandy loam. The highest underground dry weight of the tuber (63. 6 g) was observed at 12 cm depth and the lowest (0) was obtained at 32 and 42 cm depths. The results showed the highest tubers number was observed at 2 cm depth of sandy loam soil and the lowest was obtained at 42 cm depth of sandy loamy and 32 cm and 42 cm depth of sandy loamy. The number of tubers decreased with increasing planting depth in all three texture types. The highest percentage of tuber production in heavy textures (silty loam and clay loam) was formed in layers of 2 to 12 cm of the soil. Conclusion: The results showed that with increasing depth in all three types of soil texture, all the growth characteristics of purple nutsedge significantly reduced. More than 80% of the distribution and dispresal of underground organs was formed at a depth of 2 to 12 cm. The percentage of emergence decreased by 100 % at 32 and 42 cm depths of clay loam and silty loam. It seems that, the lack of emergence at the high soil depth is due to disruption of gas exchanges and lack of light. Given the importance of tubers in reproduction of this plant, this should be considered in management strategies. The deep plowing by delaying the emergence and growth and decreasing the production of reproductive organs (rhizome and tuber) of purple nutsedge can be considered as a management option. This weed has high emergence ability in the sandy loam soils due to high permeability and porosity.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Author(s): 

WANG H. | CHEN J.

Issue Info: 
  • Year: 

    2013
  • Volume: 

    10
  • Issue: 

    5
  • Pages: 

    1007-1018
Measures: 
  • Citations: 

    0
  • Views: 

    288
  • Downloads: 

    0
Abstract: 

Numerous industrial or burial sites contaminated by persistent organic pollutants such as polychlorinated biphenyls (PCBs) and pesticides were discovered in China recently. Due to improper choice of technology, many remediation cases had cost too much; however, failed to attain expected goals. In this study, the distribution and transport of PCBs at a burial site were investigated using tested PCBs concentration in order to support the choice of remediation technology and estimate the remediation results. Site characterization was carried out in order to investigate the hydrogeological condition and PCBs pollution nearby the capacitor burial site located in Shanxi, China. Results of PCBs measurement indicated that the proportion of contaminated soil with concentration above 500 mg/kg is 7.8% and the value for soil with concentration between 50 and 500 mg/kg is 18.0%. Considering adsorption and biodegradation, the two-dimensional PCBs transport model was established based on advection-dispersion equation. The model calibration showed a good agreement between measured and computed values, indicating the feasibility of this model used for predicting the transport and disappearance of PCBs in soil. Results of 100 years’ simulation demonstrated the slow migration and biodegradation of PCBs. Simulations were conducted for before and after remediation scenarios. Comparison of the results indicates that the remediation alternatives of excavation-incineration and thermal desorption have successfully removed most of the organics and thus reduced the environmental risk to a low level.

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Issue Info: 
  • Year: 

    2019
  • Volume: 

    33
  • Issue: 

    1
  • Pages: 

    111-122
Measures: 
  • Citations: 

    0
  • Views: 

    657
  • Downloads: 

    0
Abstract: 

Introduction: Eryngium caeruleum L. is a perennial weed from Apiaceae family that grows in the farm and roadside. There is limited information on the reaction of this plant germination to temperature and light conditions. Germination is one of the most important processes for weed success, because it is the first step in competition beginning in an ecological niche. Recognition of E. caeruleum germination and emergence ecology has an important role in weed management and control. Different environmental factors, such as temperature and light, affect dormancy and germination of the seeds. Light requirement is an indicator showing the level of seed dormancy. Given the significance of seed dormancy in weed dispersal and management, this study aimed at determining the relation between light and temperature as the most effective environmental factors in germination stimulation of E. caeruleum. Materials and Methods: An experiment was conducted to estimate the effect of temperature and light on germination of Eryngium caeruleum seeds at agriculture and Natural Resources College, university of Tehran in 2016. A factorial experiment was undertaken based on completely randomized block design with three replications. Factors were germination temperatures (5, 10, 15, 20, 25, 30 and 35 ° C), burial periods in 5 cm depth (30, 60, 90, 120, 150, and 180 days), and light conditions during germination test (Presence and absence of light). The seeds were buried in the soil under environmental conditions at depth of 5 cm and then removed from the soil at one month intervals and were placed at dark and light (Osram, L 18 W/77, 20 μ molm-2s-1) conditions under seven temperature treatments for 14 days. 25 seeds were placed in each petri dish and the germinated seeds were counted for 14 days in each month. Segmented model was used for studying the germination rate to temperature in light and temperature treatments. Thermal parameters of germination were calculated for light and temperature treatments. These parameters were Gmax for the maximum germination rate, Tb or base temperature for germination, To or optimum temperature for germination, and Tc or ceiling temperature for germination. The base and ceiling temperature parameters were also calculated. The findings of this study shed light on seed germination requirements of E. caeruleum and enhance our understanding of this species distribution. These results will be useful in selecting the best time and method for E. caeruleum control. Results and Discussion: Results showed that temperature and light conditions during germination test influenced germination rate. According to the analysis of variation, all simple effects and interactions were significant on germination rate. Germination rate increased with increasing temperature up to 20 ° C. Germination rate, however, decreased when temperature increased up to 35 ° C. Temperature parameters of base temperature, optimum temperature and ceiling temperature were affected by burial periods and light conditions during germination test. In general, base and optimum temperatures decreased and ceiling temperature increased with increasing of burial time. The burial time needed for 50 percent decrease of maximum base temperature in the lowest burial time was 117 days in light condition and 82 days in dark condition. The optimum temperature decreased from 23. 5° C to 21. 2° C in light condition and from 23° C to 21° C in dark condition. The ceiling temperature increased from 28° C to 42° C in light condition, but it had different process in dark condition. The Tc parameter was 30° C in 60 days of burial and was 28° C up to 120 days of burial and had no changes up to 180 days of burial. Parameters of Gmax and ai, which indicate the maximum germination rate and seed non-dormant index, respectively, rose linearly by increasing time of seed burial, irrespective of light condition during germination test. The same results were found in Circium arvense and Bidens pilosa, that their germination thermal parameters were higher in light condition than in dark. This can be attributed to the heat made by the light. The results of the experiment on Plygonum aviculare also showed the effects of light on cardinal temperatures of germination and the start of germination of this plant. Conclusion: The results showed that the thermal parameters of Eryngium caeruleum germination including base temperature (Tb), optimum temperature (To), and ceiling temperature (Tc) changed during the burial periods. The Gmax and awakeness index parameters increased linearly regardless of the presence or absence of light. It can be also concluded that Eryngium caeruleum L. has morphophysiological dormancy and dormancy breaking. Moreover, the optimum temperature range for germination mostly rises by increasing ceiling temperature.

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Issue Info: 
  • Year: 

    2020
  • Volume: 

    3
  • Issue: 

    4
  • Pages: 

    36-47
Measures: 
  • Citations: 

    0
  • Views: 

    1105
  • Downloads: 

    0
Abstract: 

One of the most important parameters in dynamic analysis and design of structures is the lateral displacements caused by loading and incitement instigations to the structure which is very important in the process of computation calculation and determination of the structure sections and dynamic parameters of the structure. In the past, in the process stage of structural analysis and determination of forces and stresses tensions and the response of the structure to existing investigations stimulus, soil and foundation and structure systems were investigated and studied and analyzed with districted and separated forms and numerous great simplifications. These studies were modeled and analyzed by with considering consideration of placing the structure on a rigid solid foundation on a soil with sufficient resistance to resist the session’ s summits and forces, which is transmitted from the structural foundation of the structure to it. Field studies and the results and observations obtained by from visiting the damaged and damaged areas of the earthquake, showed that, even at a certain location and among similar structures for in terms of shape and geometry and dynamic characteristics, the damage caused by the earthquake can could be very different, and this can only be due to the effect attributed to the impact of structure interaction-soil and foundation and such as that. The next Subsequent studies showed that the interaction of soil and foundation and structure themselves are highly strongly influenced by many parameters such as environmental factors, mechanical properties of material and soil, and the seismic characteristics form of foundation and gender, and the depth of soil and substrate seismicity of the zoning of the site of the structure and the geotechnical characteristics of the structure specifications and the like. In this study research, it tries by investigating of the is attempted to investigate these two parameters and modeling it them in the powerful software “ Abaqus” software and considering the sufficient taking into account the number of required models needed that in each of them, One of the parameters under investigation changes, the value of their effect on the dynamic response of the structures are should be studied.

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Journal: 

PETROLEUM RESEARCH

Issue Info: 
  • Year: 

    2015
  • Volume: 

    25
  • Issue: 

    84
  • Pages: 

    150-160
Measures: 
  • Citations: 

    0
  • Views: 

    1333
  • Downloads: 

    0
Abstract: 

Geological studies and mapping of surface and sub-surface structures have always attracted the attention of geologists. The main purpose of this study is the identification of salt domes in strait of Hormuz using subsurface data. The study area is located in the south of Iran, which is known as Block E for oil companies at longitude of 55-56o east and latitude of 25o30’-27o north. Seismic data, well data, and UGCtime map are used for three-dimensional modeling of the subsurface salt structures by Petrel software. In this work, the locations of 17 burial and non-burial domes in the Hormuz strait are mapped and the coordinates of the center of each dome with burial depths are written. Most of these diapirs concentrated on the western part of the strait of Hormuz and is likely that the thickness of Hormuz formation in the western part is higher than the central and eastern parts. Finally, eight domes were added to the dispersion salt domes map in Iran. The distance between each of the domes is estimated to be about 35 kilometers in marine sector and it was found that the salt diapirs in the southern Iran matched NE-SW direction or Hendurabi lineament.

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Issue Info: 
  • Year: 

    1984
  • Volume: 

    21
  • Issue: 

    -
  • Pages: 

    629-641
Measures: 
  • Citations: 

    1
  • Views: 

    198
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    1384
  • Volume: 

    24
Measures: 
  • Views: 

    819
  • Downloads: 

    0
Abstract: 

لطفا برای مشاهده چکیده به متن کامل (PDF) مراجعه فرمایید.

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Issue Info: 
  • Year: 

    2021
  • Volume: 

    12
  • Issue: 

    2 (43)
  • Pages: 

    1-15
Measures: 
  • Citations: 

    0
  • Views: 

    649
  • Downloads: 

    0
Abstract: 

Background and Objective: Biological soil crusts are a collection of lichens, mosses, fungi, cyanobacteria, etc. that are part of the soil ecosystem. Estimation of density and distribution of biological soil crusts in arid and semi-arid regions of Iran, which is the subject of soil erosion and wastage is very important. Methods based on remote sensing techniques are important in terms of cost and time less efficient methods to achieve this goal. Segzi plain is one of the critical points of wind erosion in Iran and identifying and determining the distribution of biological soil crusts as a soil modifier is an effective step in reducing wind erosion in the region. In this research, BSCI (Biological Soil Crust) index has been used to prepare the distribution map of lichen-dominated biological soil crusts. Materials and Methods: The study area is part of the Sajzi Desert (Central Deserts of Iran) which is located in Isfahan province of Iran. The study area with an area of 199. 5 hectares is spread between the eastern lengths of 51o52'32" to 52o27'41" and the northern widths of 32o33'31" to 32o55'01". The average slope of Segzi plain is 1. 08 percent and its average height is 1680 meters. According to the statistics of East Isfahan Meteorological Station (Shahid Beheshti Station), the average annual rainfall in the region is 106 mm. According to the Dumarten climatic classification, the climate of the region is dry and according to the Amberge classification it is cold. The BSCI index is a combination of the relationships used to estimate vegetation and bare soil surface, and its mathematical relationship is the slope of the soil line. To calculate the soil line in an area, one must first separate the pixels that have bare soil and no vegetation. In order to calculate the soil line equation, in four seasons of a year, images of Landsat OLI 8 satellite related to 2018 were downloaded from the site of the US Geological Survey and 20 to 30 pixels of pure bare soil were extracted by drawing the reflection values of these pixels in the red and infrared band. Red near soil line coefficients were calculated for each season in the Segzi Plain. Based on BSCI index, lichen-dominated biological soil crust are identified using at least VIS-NIR spectral reflection and the slope between the red and green bands compared to bare soil and dry vegetation. Using ENVI software, the distribution shells of biological shells with lichen dominance were prepared in four seasons since 2018 in Segzi plain. Then, the prepared maps were validated based on land points and the total accuracy and kappa index were calculated in all four seasons. The collected lichen samples were identified based on their morphological characteristics and using a stereomicroscope, conventional microscope and common color reagents such as potassium hydroxide (KOH). After applying the BSCI index on the Landsat OLI 8 satellite image, using ENVI software, spectral profiles related to 4 points of Segzi plain in four seasons of the year were prepared and the spectral reflection in four seasons of the year in different points were examined. Results and Discussion: The slope of the soil line is lower in the rainy season, which coincides with the growth of herbaceous and annual plants, compared to the summer season, which has the least amount of rainfall, and the annual plants have dried up and become extinct. In May, the slope of the soil line was minimal (0. 39) and in late summer it has its maximum value (0. 78). In fact, the slope of the soil line has decreased from mid-August to May, and then has increased with the loss of annual vegetation and the increase of bare soil surface. The distribution maps of bio-shells in all four seasons of the year were validated during field visits and the year it was found that the highest accuracy of the map related to the map produced from Landsat 8 image is related to summer with 94% total accuracy and Kappa index equal to 0. 7412. Interpretation of the spectral profiles of the BSCI index shows that the reflections of the spectra related to the zephyr and strain prepared on the lichen dispersion points are very close to each other and also the spectral profiles of the mid-autumn and early spring are quite consistent. Whereas in the faults, which did not cover the biological crust, the amount of reflection was higher and there was a slight difference between the reflection diagrams of autumn and spring. Although the reflectance values of a range of agricultural lands and the distribution points of biological crusts are very close to each other, the spectral diagrams of all four seasons are very different from each other. But in all seasons of the year and in all places, the least reflection has occurred in the beginning of winter and the most reflection has occurred in summer. The climate of Segzi plain is Mediterranean and precipitation occurs in the cold season of the year. Simultaneously with the increase of precipitation from the middle of autumn, annual plants and mosses at the base of shrubs begin to grow and reach their peak in early winter and again at the beginning of spring. Decreases in rainfall have reduced their density. If the winter spectrum has the least reflection in all places. While in late summer, when the annuals and mosses have dried up, it has had the greatest spectral reflection. In Fasaran, which is a barren area and a landfill, it has shown its maximum reflection. Therefore, the BSCI index relative to the percentage of organic matter has a significant error in the detection of biological soil crust and where the organic matter is high may not provide accurate diagnosis of soil bioshells. Of course, since the BSCI index is defined for the detection of throat compounds in lichen tissues. The error rate for organic matter is reduced to a minimum. As it has been observed in the final map, there is no cover of biological soil crusts in Fasaran and only soil biological crusts are observed in the areas around Fasaran in the agricultural areas. In agricultural areas, due to human intervention and cultivation, the amount of annual plants is different from the field of natural resources in different seasons of a year have become. Conclusion: Spectral similarity of the most important soil surface, including vegetation, the involvement of human factors in increasing or decreasing soil organic matter, bare soil, etc. limits the efficiency of the BSCI index and therefore in the time period of satellite images and regional conditions have a great impact on It has the accuracy of BSCI index.

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