فهرست مطالب ابوالفضل رنجبرفردویی

Dust storm is one of the desertification and land gegradation consequences especially in arid and hyper-arid regions of the world. Fine particles released from the Earth's surface can be released several kilometers and subsequently over long distances, sometimes even across continents. These particles play a key role in the Earth system by affecting the radiation balance as well as forest and ocean ecosystems. Weather is often considered as the main factor influencing the occurrence of dust storms. Dust storms have increased in recent years mainly due to continued droughts and global warming. Temperature is an important variable in climatilogy in terms of its direct effect on weather variables such as pressure, wind movement, cloud formation and precipitation. Based on previous studies, the increase in temperature along with the decrease in rainfall and the increase in wind speed provide the conditions for the creation of dust storms. In general, the review of the studies conducted in the field of evaluating dust changes and the effect of temperature parameters on it shows that it is possible to conduct these studies from different perspectives and methods. Therefore, it is necessary to find a comprehensive view on dust and factors affecting it by reviewing and evaluating the results of other studies so that the phenomenon can be controlled and managed. The number of dusty days in Khuzestan province is significant and has increased in recent years. The reason for that is its proximity to the great deserts of the neighboring countries. Therefore, this province is one of the challenging areas of the country in the field of dust management and control. The purpose of this study is to evaluate the trend of dust changes and the effect of temperature on this phenomenon. The results of this study help to better understand the phenomenon of dust in Khuzestan province.

In this research, three data groups were used including the monthly average temperature of 13 meteorological stations in the study area, the monthly average land surface temperature (LST), and the monthly average aerosol optical depth (AOD). First, the trend of dust changes was evaluated using the Mann-Kendall test. Then, the relationship between temperature parameters and dust was investigated using the correlation between the AOD in a buffer of 5 km around the selected stationwith temperature parameters including monthly average temperature and average monthly LST in buffers of 5, 10 and 20 km around the selected station.

The evaluation of the average changes in the buffer of 5 km around the selected stations showed that in the months of February, July, December and April, no increasing trend was observed in any of the stations and even in the month of April, there was a decreasing trend in two stations. The trend of AOD changes was increasing with a probability of more than 90% in the months of August, September and November in seven, March in five, October in four, January in three, May in two and June in one station. The correlation results of temperature parameters and AOD showed that a very strong correlation between average LST and AOD has occurred only in the three months of May, June and July in different buffers. There are the highest number of strong correlations in the months of May to August between temperature parameters and AOD. Also, the highest number of very weak correlations occurred in April, March, November, and December. The highest number of very weak and weak correlations are related to air temperature (85 and 47 numbers, respectively). This shows that LST is more important than temperature in evaluating changes in dust intensity in the study area.

According to the results of this research, it can be said that air temperature has a weak correlation with dust, and most of the strong and very strong correlations occurred with the average LST in different buffers, which shows that LST is more important than temperature in evaluating dust intensity changes in the study area. In general, evaluation and monitoring of dust changes can be effective in identifying new dust sources as well as evaluating wind erosion, dust control, and management activities. Therefore, it can be suggested that an online and up-to-date system based on remote sensing and artificial intelligence be designed and presented to evaluate and monitor dust changes. In this case, the management of the dust phenomenon in Iran will be more targeted and the dust sources can be identified faster. On the other hand, one should pay attention to the factors affecting these changes and evaluate their effect on dust.

Dust particles originating from internal and external sources have adverse effects on public health and the environment. Considering the unknown contribution of the mentioned resources to dust production, it is very important to investigate this issue in different regions of Iran. In addition, the analysis of spatial and temporal changes of events with different origins can be an effective step toward identifying areas more sensitive to the phenomenon of wind erosion and reducing the risks caused by its occurrence in the affected areas. The present study was conducted considering the mentioned topics as the main objectives. For this purpose, internal (codes 07-09, 98 and 30-35) and external (code 06) dust phenomenon statistics recorded in 11 synoptic stations of Kerman province in the common time frame of 2002-2020 were used. After calculating the frequency of events, the contribution of internal and external dust sources in different regions of Kerman province was determined. Using the classified map of the dust events occurrence frequency and Mann-Kendall test were respectively analyzed their spatial and temporal changes. The results showed that in the three cities of Jiroft, Anar, and Sirjan, the contribution of external events was higher than other regions of the province, about 80%, 53.8%, and 53.2%, respectively. The contribution of internal events in Shahrbabak, Rafsanjan, Shahdad, and Baft was more than 73% and in Zarand, Kerman, Bam and Kohnuj more than 52%. On average, the share of internal and external events in Kerman province was estimated to be 60.6% and 39.4%, respectively. The spatial distribution pattern of internal and external dusts showed that Bam and Jiroft were the most sensitive areas to wind erosion in the study period. In the study period, the events originating inside and outside the station in Shahdad and Zarand had a significantly increasing trend. A significant increasing trend of events with internal origin was observed in Kohnouj, Rafsanjan and Anar, and an increasing trend of dust originating outside the station was also observed in Sirjan (Z>+1.96).

In this study, drought was investigated on water use efficiency (WUE) in different climates and uses of Tehran province. To calculate the efficiency of water consumption, the products of Gross primary production (GPP), Evapotranspiration (ET) and Palmer drought severity index (PDSI) obtained from the MODIS meter are used. Then the trend of changes in the index of primary gross production, evaporation and transpiration, water consumption efficiency and drought in the period of 2001-2021 using linearity and Mann-Kendall and slope tests, and then the response of water consumption efficiency to drought in different climates and consumptions with Use. It was evaluated from correlation analysis. By dividing annual rainfall into potential evapotranspiration (PET), the Aridity index (AI) was calculated and climate classification was done with the help of this index. The results showed that the indices of evapotranspiration, primary gross production and drought increased by 81.15, 86.86, and 99.99% respectively, and the water consumption efficiency index decreased by 76.24% in this 20-year period. Is. These results were confirmed by the slope test. Examining the relationship between the efficiency of water consumption and drought in different climates and applications showed that in dry climates, agricultural land and bushland had a negative ratio of 91.86 and 78.93, respectively, and pasture consumption had a positive ratio of 51.96. Agricultural lands, pastures and bushland related to semi-arid climate have increased by 85.38, 66.22, and 64.27 percent, respectively, and forest use has decreased by 84.87 percent. In semi-humid climate, respectively, 47.53, 60.48, 73.41% of the study area has a positive relationship in the use of agriculture, pasture and shrub land, and 91.30% of the use of forests has a negative relationship. In the climate, the negative impact of drought has been in 66.04, 61.15 and 50.56 percent of agricultural, pasture and forestry lands. In general, according to the mentioned results, drought has had a negative effect on water consumption in Tehran province, and it can be said that the resistance of the ecosystem against drought is determined by our correlation between drought index and water consumption efficiency.

Maintaining soil structure and stability is essential, especially in arid and semi-arid regions with poor soil structural stability. Destruction of soil and its crust can cause wind erosion and desertification. The objective of this study was to investigate the effect of using hydrogel nanocomposite mulch on the stabilization of sand surfaces. A wind tunnel test was used to evaluate the erodibility of samples treated with different amounts of hydrogel nanocomposite. The compressive strength of the samples was measured by a manual penetrometer. The prepared nanocomposites were examined using scanning electron microscopy (FE-SEM), infrared spectroscopy (FTIR), and X-ray diffraction (XRD) images. The results of the wind tunnel showed that the addition of hydrogel nanocomposite to the samples improved the soil erosion rate by 100% at a speed of 15 m/s compared to the control sample. Bonding between sand particles by spraying hydrogel nanocomposites improves the erodibility of sand. Measurement of mechanical strength of treated samples after 30 days showed that the resistance of the crust increased with increasing the amount of nanocellulose in the composite, which can be expressed due to the increased surface area of the nanoparticle and the possibility of further bonding of the nanocomposite polymer bed with sand particles. While the crust diameter showed no significant difference with increasing concentration and the sample treated with nanocomposites containing 3% nanoparticles was thicker compared to other samples.

One of the new and unique sections, especially in internal studies, is the quantitative examination of unevenness. The scientific and quantitative study of topographic position has always been one of the topics that have received little attention in domestic research. So, classification and identification of different morphometrically distinct regions are necessary. Thus, the present study aims to classify landforms in the northwest of Fars province, Kharestan region and investigate its factors affecting. In this regard, the Topographic Position Index (TPI) method was used in the first stage to classify landforms, followed by the CORINE method to determine erosion risk classes. Additionally, Landsat 8 satellite images from June 2017 were used to determine the normalized differential vegetation index (NDVI). The next step was to determine the relationship between different types of landforms and terrestrial factors such as height, slope, slope direction, topographic wetness index (TWI), Terrain Ruggedness Index (TRI) and NDVI. Finally, the status of different landforms was determined based on erosion risk classes. Results showed ten different types of landforms existed within the study area. Small plains (1.18%) were the lowest in the study area, while waterways (27.71%) and high peaks (27.48%) were the highest. The TWI was significantly correlated with landform classes at 95% level. Most of the region (91.71%) had NDVI classes of 0.1 to 0.3. Stream and u-shaped valleys were found to have higher NDVI values. Real erosion risk was classified into three classes: low, medium, and high with areas of 31.14, 31.11, and 37.78%. There were 44, 57, and 59% erosion levels in the low, medium, and high erosion classes, respectively.

More than 40% of the global lands are covered by arid and semi-arid areas, a quarter of which is covered with dunes, On the hand, wind erosion contributes by approximately 60% to desertification. therefore, additives or stabilizers are used to control wind erosion and decrease its adverse consequences.Soil stabilization refers to process whereby a product is added to the soil to improve its properties. stabilizing agents are typically classified into traditional and non-traditional types. Hydrogel as a non- traditional stabilizer is a hydrophilic polymer with a three-dimensional network. In recent years, researchers have developed a series of polymers to be used for various purposes, including the enhancement of soil properties. In this regard, this study sought to investigate the applicability and effectiveness of co-acrylamide acrylic acid hydrogel and determine its optimal concentration as a stabilizer of sand surfaces. To achieve the optimal concentration, a completely random experiment design was performed in the SPSS environment with three repetitions for all three concentrations of 0.5, 1, and 2%.

Collected from the Siyazgeh desert in northern Isfahan province, Iran, the samples of sand dunes used in this study. To investigate the efficiency of the chemical additives used in this study on the sandy soil’s properties, the polymer was used at three levels (0.5, 1, and 2%) with 3 replications. Accordingly, metal trays with 100 × 30 × 2 cm dimensions were used to administer the wind erosion test and determine the threshold of friction velocity. Then, the control tray and the treatments were tested under different wind velocities (the comparison of the samples’ weight before and after the wind tunnel test showed a weight loss). Finally, the effect of polymers on anti-wind erosion ability was studied in terms of compressive strength, abrasion resistance, impact resistance, and crust diameter.

Determination of wind friction velocityThe effect of three different concentration solutions on the shear strength suggested that all three treatments were resistant to maximum wind velocity (15 m/s, duration time was 20 min) and they didn’t lose weight. On the other hand, the control treatment showed 5 m/s for the threshold of friction velocity.Treatments ResistanceThe results of variance analysis showed that there was a significant difference between the treatments (sig <0.05) and compressive strength in different concentrations, and that increased compared to the control sample. While treatment 3 had the highest resistance (1.61±0.18), no significant difference was found between treatments 1 and 2 (Figure 1).As shown in Figure 2, treatments 3 and 1 had the highest and lower resistance against the sanding (46.67±5.19 and 8.67±0.96), respectively.The samples treated with 2% polymer revealed the highest sheer resistance (5±0.56) (Figure 3). As shown in Figure 4, only treatment 3 was impact resistant.   As shown in Figure 5 most crust diameter revealed in the sample treated with 2% polymer (15.63±1.74).

Considering the results of this study, it could be argued that composite concentration plays a key role in the influence of polymer adsorption on the soil’s particles. on the other hand, it was found that the sand’s strength and stiffness increased with an increase in the concentration of the polymer solutions, which could be justified by an increase occurred in the interaction between sand particles and additive.

Vegetation is one of the essential factors in structure and function of terrestrial ecosystem and it is one of the principal loops in water-soil-plant-atmosphere continuum. Several studies have demonstrated that vegetation covers are sensitive to alteration of climatic, edaphic, topographic and human activities. Thus, alteration in vegetation and its relation with the mentioned factors are important of high importance. In order to investigation of vegetation changes and its effective factors, the current study was conducted in Kharestan region placed in Fars province, Iran. In this regard, the images obtained from ETM Landsat 7 (2000-2017) and meteorological data gained from local and 17 regional meteorological stations were used. Using these images, temporal and spatial changes NDVI and NDVI anomaly were studied. A supervised classification method was used to extract land use map. Finally, the relationship of NDVI with climatic, topographic and anthropogenic factors was investigated. Relationship between NDVI and climatic and topographic factors was estimated using GWR and OLS methods, respectively. Generally, temporal variations showed a slow increasing trend in NDVI value. NDVI anomaly was mostly negative before 2008 but it turned to positive after 2009. NDVI spatial distribution showed an increasing tendency from north toward center and continued to south-west of the study area. The study shows that the vegetation cover change was caused by both natural factors and human activities. NDVI increased in agricultural and pasture lands. Also, natural vegetation has been affected by climatic factors more than irrigated vegetation (agricultural and gardens). Furthermore, vegetation variation influenced by topographic factors likes height, slope and aspect. Also, with an altitude over than 2500 m, NDVI showed a decreasing trend, on slopes lower than 5° it increased. NDVI values in north and east directions were higher than in southern aspects. The overall trend indicates an increase in temperature and a decrease in precipitation during the study period. The maximum positive and negative correlation between mean annual precipitation and NDVI using ordinary least squares method were 0.93 and 0.83, respectively. Also the maximum negative and positive correlation between NDVI and temperature were 0.65 and 0.5, respectively. The highest local R2 values between NDVI with precipitation and temperature were 0.45 and 0.44, respectively, which was observed in the central parts of the region. According to the obtained results through the present study, it can be stated that environmental factors like precipitation, altitude, slope and aspect are the Influential factors controlling vegetation in Kharestan (Fars province, Iran).

Drought and its effects is one of the world's major concerns. As one of the countries in the dry belt of the earth, Iran has always been and is facing environmental issues and natural hazards caused by drought. Therefore, this study aimed to monitor the aridity in Sistan and Baluchestan using remote sensing data and geographic information system techniques for over a period of 15 years (2015-2000). In this regard, the MODIS satellite images from 2000 to 2015 were analyzed by applying the yearly Precipitation Condition Index (PCI) and Standardized Precipitation Index (SPI). Then, the drought changes were evaluated using supervised classification method and difference images. The results showed that the years 2007 and 2001 with an area of 157383.06 and 306.05 km2 had the highest and lowest levels of precipitation, and also with an area of 49511.1 and 69233.83 km2 had the minimum and maximum level of drought, respectively. The most severity change of drought has been in time for the 2002-2001 period and the place also belong to parts of Khash, Iranshahr and Sarbaz who takes 194302.93 km2 of the province. Finally, the general trend of changes in precipitation and drought is decreasing and increasing, respectively, requiring the major planning of resources conservation and risk and crisis management to rehabilitate and maintain the ecosystem of arid regions.

Iran is frequently exposed to local and synoptically dust storm due to the geographical location of Iran. In recent years, dust storm frequencies and intensities have been increased significantly in Iran and especially in Isfahan Province, seriously disrupting human life and affecting the quality of life. This phenomenon is particularly increased in the spring and summer. Climate factors play an important role in dust storms. In this research, spatiotemporal changes of climate factors and dust storms were studied. Therefore, we analyzed climate factors (precipitation, temperature, wind speed and humidity) and dust storms frequency during 1992 to 2016. Poisson regression model was used for statistical modeling of temporal and spatial variations of dust and climatic parameters. According to the models, there was conformity between the results and the predicted values throughout the months. In addition, the results showed that wind speed played a major role in the occurrence of dust storms and had the highest coefficient. The results also showed that most of the dusty days are in the spring and then in the eastern part of the province, which is related to the local centers in the eastern part of the province and summer winds.

Dust event is one of the secondary complications of ecosystem in arid and semi-arid areas. This phenomenon results from system feedback against multiple factors of pressure and destruction. One of the most important foundations of ecosystems is vegetation. Because the vegetation factor reflects many factors in the ecosystem, therefore, the interaction of factors can be understood by studying the relationship between its changes and other factors such as dust phenomena. The aim of this study was to investigate the effect of vegetation and relationship with dust events in Esfahan province during 2000-2016 using Geographic information system and Normalized difference vegetation index. The data of dusty days in the region synoptic stations were provided from Meteorological Organization and the frequency of dusty days in different years were determined. Using the method of Normal Kriging in GIS; dusty days were zoned. Vegetation map was prepared based on NDVI in July for each year using MODIS image. The regression analysis of annual dust and vegetation index were also performed to quantitatively analyze the effect of vegetation cover on the occurrence of dust.The results showed. Vegetation cover has been the lowest during the study period in the east and center of the province. The NDVI was also the lowest in 2011-2012 and 2015, with a change from 0.69 to -0.19. The results showed significant correlation between the number of dust event and vegetation distribution

Erosion plays an important role in desertification process that its evaluation leads to better understanding of desertification potential. The sparse vegetation cover, low humidity and the scarcity of rainfall can make Jaz-Murian region prone to soil erosion and desertification. In this research, the sensitivity of the Jaz-Murian region to the desertification on the basis of erosion criteria is evaluated using IMDPA model. In this research, the work unit map was created using geology, land use maps and Landsat 8 satellite imagery data. Water erosion indices were weighted based on the IMDPA method, and the IRIFR model was applied to evaluation of wind erosion. Finally, in order to represent desertification hazard, the water and wind erosion criteria were combined with each other in ArcGIS 10.1 software by calculating geometric mean of their indices. The findings of this research showed that the largest area in this region (approximately 5674 km2) classified in high class of desertification hazard. This means that the erosion factor play an important role in desertification process in the Jaz_Murian region. As well as, in comparison with water erosion, the wind erosion showed more effects on desertification because of the low level lands, recent droughts and subsequently the reduction of the humidity that can help to separate the soil particles and increase the erodibility. The work units including: "clay plain covered by degraded Nebka and Reboh”, “clay flat with separated Tamarix and Prosopis species”, “clay and salty lands covered by dominant vegetation of Seidlitzia rozmarinus and Hamada salicornica” and “Erg and sand dunes” showed the highest sensitivity to wind erosion that need to be in priority of the de-desertification plans. According to the findings, it concluded that about the 97% of the study area is located in the high class of desertification hazard that needs to reduce the effects of erosion by introduce management strategies to combating desertification . As well as, rec lamation of vegetation covers and its conservation regarding ecological aspects can help to reduce erosion effects and de-desertification.

Reduction of species diversity which is a significant threat to the earth has been found more important and has attracted attention among ecologists over recent years. This research was carried out to determine the relationships between plant species diversity indices and soil properties by multivariate regression methods in Jamilabad region, Baft, Kerman province, Iran in 2016. Different sites of natural ecosystem (including non-grazed, moderate grazed and over-grazed rangeland) and disturbed ecosystem [including rangelands plowed to Glycyrrhiza glabra root harvesting and abandoned dry land for ten years (Fallow) sites] were selected by fieldwork with the same climate, topography and geological factors. Abundance and canopy of species and soil samples (0-20 cm) were taken from each site contemporary for multivariate regression model and its validation. Determination of species diversity indices was done by PAST and BIO-DAP packages. Results revealed that regression models had higher accuracy in the disturbed ecosystem. In this regard, soil erodibility factor as well as soil total nitrogen explained 80% and 77% total variation in both Shannon-Wiener and Margarof indices, respectively. Results showed that even though the soil erodibility was excluded from the model, its components such as organic matter (in Berger-Parker index) had an important role in plant diversity. Therefore, soil erodibility or its components were strongly affected by plowing in the disturbed ecosystem and led to the formation of strong regression models between soil properties and species diversity indices.

Energy is one of the most important factors in the development of human societies and is one of the essential factors in economic, social development and quality of life.Population explosion and growing energy demand, increasing living standards, the risk of global warming due to the greenhouse phenomenon, falling of acid rains, environmental problems and threats to human health, and finally lack of fossil energy sources are among the issues that attract the attention of the world's nations to the use of renewable energies,so that, in their planning, they take the provision of a percentage of the energy needed by their country through wind turbines, solar energy, geothermal energy and other renewable energyinto considerations. Due to the limited resources of fossil fuels and savings for future generations, there should be a need to replace and use renewable energies such as solar energy. More than 85% of Iran's territory is covered by arid and semi-arid regions, where the energy share of solar radiation is high.Solar energy, as one of the sources of clean energy and free from environmental degradation, has long been used in many ways. Due to the limitation of fossil sources and their pollution, as well as the increasing demand for energy, it is necessary to take measures to optimize the use of the solar energy source in Iran.
Given that most of the work done in the field of estimating radiation energy has been made using weather or climatic data such as temperature, cloudiness, radiation, etc., and remote sensing data and satellite imagery have not been used generally, therefore, the purpose of this research is to investigate the radiation potential in a part of the central regions of Iran using remote sensing data and albedo, brightness, vegetation, moisture and land surface temperature indices.

Material and Methods: The study area is situated in central region of Iran in the geographical range 33º, 41ʹ,50ʺ-35º, 28ʹ, 30ʺ northern latitudes and 50º, 41ʹ, 40ʺ-52º, 30ʹ, 27ʺ eastern longitudes. The present research is an applied one, and its methodology is a combination of remote sensing and Geostatistical analysis. The data used in this research was obtained from the May 17, 2015 images of Landsat 8 satellite, with the course 164 and the row 36. In order to study the radiation potential, indices such as albedo, brightness, NDVI, greenness, moisture, and ground surface temperature were used. To calculate each of the aforementioned indices, the equations and functions related to each index on the Landsat 8 image were used in ENVI 5.3 and GIS 10.3 software. In order to calculate the Earth's surface temperature index (LST), the thermal bands 10 and 11 of Landsat 8 must first be converted into the radiance, and then to the brightness temperature, and finally to the temperature of the satellite's brightness. Then, the map relating to each standardization index, and the potentiometric map were prepared by takingthe mean of all indicators. Finally, the potentiometric map was also classified into five classesaccording to the estimated amount of solar radiation, including very inappropriate, inappropriate, moderate, appropriate, and very appropriate. The results obtained from Albedo, brightness, NDVI, greenness, moisture and land surface temperature indicators are shown from low to high. For Albedo index, the least amount (6668.87) was observed in the northwest of Qom, south ofGarmsar, southwest of Abu Zaidabad, Niasar, Golestan, northwest of Kashan, and the highest amount (61352.7) was observed in the northern parts of Garmsar, south and southeast of Qom, and West of Aran-o-Bidgol. For the brightness index, the lowest value (15441.9) was observed in the northwest of Qom, south ofGarmsar, southwest of Abu Zaidabad, Niasar, Galak, northwest of Kashan, West of Pishva, Gharchak, and the highest amount (129881)was observed in northern parts of Garmsar, Center and South and South West of Qom and West of Aran-o-Bidgol. For NDVI index, the lowest vegetation cover (-0.393175) was seen in the central and northwestern parts of Qom, south of Garmsar, Abu-zaidabad, north ofAran-Bidgol, northeast of Kashan, and the highest value (0.639655) was observed in the northeast of Garmsar, Qarchak, Pishva, Northwest of Javad-abad, south of the Kahak, west of Niasar, southeast of Kashan. For the greenness index, the lowest value (-43887.6) was observed in the northern parts of Garmsar, in the north of Hassanabad, south and southwest of Qom, south of Javad Abad, southwest andcenterofKashan, west and southwest of Aran-o-Bidgol, and the highest value (-3385.181) was observed in the southern parts of Garmsar, Niasar, Kahak, Northwest of Kashan, Center and Southeast of Abu-zaidabad. For the humidity index, the lowest and highest values (-52599.1 and 11.56 respectively) were seen in the northwest of Qom, south of Garmsar, southwest of Abu-zaidabad, Niasar, and northwest of Kashan. For the LST index, the lowest value (19.585) was observed in Qarchak, Javadabad, southern Garmsar, southwest of Abu Zaidabad, Niasar, Kahak, north and northwest of Kashan and the highest value (577.557) was observed in Garmsar, central Qom, West of Aran-o-Bidgol, eastern and northeastern parts of Abu-zaidabad.
The results of the land suitability analysis showed that the solar radiation potential ranged from 0.13882 to 0.71867. These values show the regions with less radiation as it gets closer to 0.13882, and more radiation as it gets closer 0.741867. The regions were classified into 5 categories includingvery appropriate, appropriate, moderate, inappropriate, very inappropriate, on the proportionality analysis map according to the solar radiation potential. Surface temperature and radiation are two important factors for the study of solar radiation. Based on these two factors, the best regions with the highest radiation potential and the highest albedo and the highest surface temperature were observed in Aran-Bidgol and Abouzid-Abad regions. The highest value (61352.72) of albedo was observed in the eastern part of Aran-o-Bidgol. However, the highest brightness value (129881) was found in this region. Based on Spatial Approach Analysis Map of solar radiation, the west of Aran-o-Bidgol region has the highest amount of radiation. Based on the results, it can be concluded that the places whereverthe Albedo and the brightness indices are higher, NDVI and greenness will decrease.
As a result, the albedo index has a direct correlation with the brightness index and an inverse correlation with NDVI index. Therefore, in the central regions of Iran, it is possible to determine the appropriate regions in terms of radiation potential through quantitative and qualitative calculation of suitable indicators such as albedo, temperature and brightness through remote sensing data and the relationships between each of these indices. Finally, it determines the best areas for acquiring solar energy and the construction of solar power plants. It is suggested that the remote sensing indices be combined with radiation models in order to obtain more accurate information in a shorter time and at a lower cost.

Dust is considered as one of the most widespread air pollutants. The objective of the study was to analyze the effect of dust load on the leaf attributes of the nut pistachio tree (Pistacia vera L.) planted in Badrood region (Kashan, central Iran) with a relatively high aeolian dust pollution. Some leaf characteristics including specific leaf area (SLA), relative water content (RWC), leaf nitrogen content (LNC), leaf phosphorus content (LPC), total chlorophyll content (TCC), total soluble sugars (TSS), ascorbic acid (AC) and air pollution tolerance (IPTI) indices were evaluated. Increasing of dust load led to aggravation of state of stress in most of the parameters studied. However, IPTI and AC indices were increased with increasing the dust load. Even though all studied traits were affected by the dust load but RWC, LNC, TCC were amongst those that were less affected and SLA, AC, IPTI, TSS and LPC were more influenced by different quantities of dust load. It may be concluded that the long-term exposer of the plant photosynthetic surfaces to dust particles leads to significant changes in biochemical and biophysical attributes, which can lead to a decrease in pistachio productivity.

The correct management in natural ecosystems is not possible without knowledge of the health in its sectors. Vegetation is the most significant sector in ecosystem that has important role in its health. Resilience is one of the defining features of health vegetation The term resilience was first introduced in the study of ecological systems and demonstrates the ability of the ecosystem to maintain its performance in the face of environmental disorders. A resilience-based system is not only equipped with a disorder adjustment mechanism but also has the potential to benefit from changes in a way that lead to creating an opportunity for development, innovation, and updating. Therefore, when a change occurs, the resilience provides the needed conditions for restarting and reorganization. If this goes beyond disturbing forces, the system will have the power to return to the maximum vegetation density with the least erosion effects, otherwise the system will be vulnerable to the change that was created and could already be controlled. This research was done in part of North east of South Khorasan province (arid climate) with the aim of quantifying vegetative resilience on behalf of ecosystem health in response to drought occurrences and long-term precipitation changes, as environmental disturbances. Therefore first, using daily precipitation data from 15 meteorological stations around the study area, their annual precipitation was extracted and was standardized by Standard Precipitation Index (SPI) over the course of thirty years (1986 - 2015). Then, the SPI index data in 15 stations were interpolated by ArcGIS software based on Inverse Distance Weighted (IDW) method and dry, wet and normal years was estimated in the study region for each year. On the other hand, from archive of satellite images of Landsat 5 and Landsat 7, an image was created for each year in study period, between 15 June and 15 July, with permanent coverage at the best of growth. Following the necessary corrections for satellite images, the average Transformed Normalized Difference Vegetation Index (TNDVI) was obtained of each image by ENVI software. Finally, effected of precipitation changes on mean TNDVI was assessed and vegetation resilience was stabilized whit selected of sever time period samples based on four effective parameters (Amplitude, Malleability, Damping and Hysteresis). Comparison of annual precipitation variations in the thirty-year time series (1986 -2015) indicated two approximate wet and dry periods in study area. The wet period is related to the first fourteen years of the time series (1986-1999) and the dry period is related to the last sixteen years (2000-2015). In this term, severe precipitation incidents with different intensities were occurred in the study area including one case of very intense precipitation (1986), one case of intense precipitation (1991) and two cases of moderate precipitation (1996 and 1992). Also, four drought incidents were occurred including one case of intense drought (2001) and three cases of moderate drought (1987, 2006 and 2008). All precipitations (wet years) are related to the first half and most droughts are related to the second half of the studied period. In this study for fixing of vegetation resilience in study area and for calculating of its parameters, In addition to the thirty-year time series selected sever time sections. in the whole study series (1986 - 2015), maximum of mean TNDVI (49.37 %) was in 1986 (reference), the lowest mean TNDVI (43.58%) was in 2010, The year effect of the decrease precipitation and drought, and mean TNDVI in 2015 was 44.28 %. Amount of parameters amplitude, malleability and damping are respectively 5.79, 0.7 and 5.09, and hysteresis was zero (%). The result of this case showed that the vegetation has moved towards the reference state (Resilience) but has not reached to amount of reference vegetation. The most specific cases for vegetation resilience happened from 1986 to 1996 (wet period) and 2003- 2009 time sector (dry period). In the first time section amount of amplitude and malleability were 0.64 %, damping was zero and hysteresis was 0.25%. The result of this case showed that not only the vegetation was returned to the reference state but also was increased to the reference (Cross reference).So despite the reduced rainfall and occurrence of sever occurrences of drought in dry period, hysteresis parameter (0.05 %) observed in 2003- 2009 time sector too that confirmed clearly vegetation health in study area whit dry climate. Awareness of the health status of the vegetation and its response to long-term precipitation changes and environmental disorders, such as drought occurrence, ensure the success of the managerial plans for renewable natural resources. The present study is the second study on quantifying the vegetation resilience and the first study under dry climatic conditions in Asia (an average annual precipitation of 160 mm) conducted in Iran by calculating four factors related to resilience, and is the first study that has presented the factor hysteresis in the calculations. Despite continuous of difficult condition, the native vegetation of the study area has been able to return the reference state not only by resolving the disorder relatively, but also it has experienced hysteresis stage. A set of quantitative calculations showed despite reduced annual precipitation and drought events, vegetation has been able to maintain its resilience, which indicates the health of the vegetation in the studied ecosystem. With the presence of such amazing protective and consistent mechanisms in the vegetation of arid regions, it is possible to maintain and restore these regions by proper managerial plans.

Given the extent of saline lands in Iran, cultivation and utilization of halophytes and salt tolerant species under the condition that both water and soil are saline could be a viable option in production and extraction of vegetable oils from halophytes and salt tolerant species. The aim of this study was to investigate the potential of three halophytes namely: Suada fruticosa, Seidlitzia rosmarinus and Aeluropus littoralis as a source of edible oil as well as quantitative and qualitative oil analysis. For this purpose, seeds of three halophytes werecollected from saline soils of Aran & Bidgol, Iran. The extraction of fatty acids was performed bysolvent in Soxhlet method, and GC was used to analyze the fatty acids. The oil yield obtained from Suada fruticosa, Seidlitzia rosmarinus and Aeluropus littoralis was calculated to be 6.61, 5.73 and 2%, respectively. According to the results of seed oil analysis by gas chromatography, The seeds of halophytes species contains 16 fatty acids as: saturated fatty acids Butyric acid, Caproic acid, Caprylic acid, Capric, Lauric acid, Myristic, Palmitic acid, Stearic acid, Arachidic acid and un-saturated fatty acid Myristic acid Palmitoleic acid, Oleic acid, Elaidic acid, Linolelaidic acid, Linoleic acid, and y- Linolenic acid. Our results clearly indicate that the seeds of halophytes especially S. fruticosa could be used as a source of edible oil for human consumption.

Desertification is land degradation in dry lands because of climatic factors and human activities. Although the ecological conditions in these areas are hard and fragile, there are some plants which can tolerate these circumstances. This study investigates the effects of alkaline water irrigation on nitrogen content and biochemical parameters of Tamarix aphylla under greenhouse conditions at University of Kashan. Tamarix aphylla is an important factor against desert thunderstorms. The plant cuttings of Tamarix aphylla were analyzed following a completely randomized design with four replications. The study treatment included: a control and four treatments at different alkalinity levels (pH=8.5, pH=9, pH 9.5, and pH=10). Chlorophyll a, chlorophyll b, chlorophyll (a), carotene, and nitrogen were measured. The statistical analyses of data were carried out using SPSS software (version 16). The results of analysis of variance showed a significant difference (p

IntroductionRange plants have important and crucial roles in medicinal industry andtogether with scarcity and low quality of the water and soil resources, prevent a quick recovery of the soil plant covering. Because of these restrictions, it is important to consider the use of salt and drought tolerant species for plantation and to preserve plant cover. In this sense, the use of native species such as black cumin (Bunium persicum Boiss) may be of interest due to their medicinal characteristics and potential ability to adapt to adverse conditions (dry and saline conditions). Black cumin (B. persicum) as a medicinal plant plays a vital role in Iranian medicine so there is a need to know about the factors affecting their growth and propagation.
Materials and MethodsTo investigate the effects of drought and salt stresses on germination and growth in black cumin two separate experiments were conducted. Drought stress was applied through incubation in four different concentrations of PEG 6000 that provide solutions with water potentials ranging from -0.2 to -0.8 MPa (including control and four levels of dryness). Salinity treatments (including control and four levels of salinity) were prepared by adding molar concentrations of NaCl to provide a range of salinity from 50 to 300 mM. Germination percentage and speed was calculated by computation of germinated seeds every day. Growth parameters (rootlet, shoot and seedling length total), allometric index and seed vigority were obtained accordingly.
Results and DiscussionSeeds under both drought and salt stress showed significant reduction in germination percentage, germination rate, radicle length, plumule length, and alometric and seed vigor indices. This trend was much pronounced under high levels of NaCl and low levels of water potentials, so that germination at Ψs = -0.6 MP was completely stopped.
ConclusionsAssessment of drought and salt stresses on germination and growth in black cumin is very important in the management of its planting. With increasing salinity and drought levels, the germination reduced significantly. Although due to higher germination of seeds in different levels of salinity rather than drought, this species seems to be more sensitive to drought stress.

Vegetation is one of the most important ecosystem components that is constantly being adapted or altered to the final balance under the influence of environmental factors. One of the most important signs of the health of the vegetation and the consequent ecosystem health is its ability to resilience after the removal of environmental turbulences. Although vegetation in arid and semi-arid areas has different methods for dealing with destructive forces, the continuity of these factors can disrupt the ability of vegetation to return to its original state after eliminating the destructive factors. The result will be the disease and, ultimately, the destruction of the ecosystem. Therefore, detection, prediction of ecosystem changes over time and management of such changes is of great importance. This research was carried out in the Namakzare Khaf watershed basin in South Khorasan Province with the aim of studying and qualitative determining of ecosystem resilience vegetation to severe changes in long-term precipitation and drought as environmental turbulences. For this purpose, the standardization of annual rainfall during the thirty-year period and the determination of the duration and severity of dry, wet and normal periods was performed with SPI method and then the ecological resilience of the vegetation was examined qualitatively based on the mean plot and Transformed Normalized Difference Vegetation Index (TNDVI) variance. These changes were studied using landsat satellite images in the final growth season of vegetation. Results indicate the mean ability to resilience and restore vegetation in the study area after the elimination of severe to medium droughts. According to the results, the ecosystem health of the studied area was confirmed on the basis of vegetation resilience, despite being located in dry land and facing severe droughts with continuity of two years and continuation of rainfall reduction compared to the mean for 6 years.

Land degradation and desertification has intensified by the interaction of climatic factors, land use change and human pressure in recent decades. Awareness that desertification is taking place in which ecosystems, the most important step to control and deal with this phenomenon. The aim of this study was to determine sensitivity to desertification Lorestan province ecoregions using life cycle assessment. For this purpose, the study area was classified into six ecoregions in terms of climate and dominant type of vegetation. Then selected indicators of drought, water erosion and excessive extraction of groundwater as the evaluation criteria. Indicators were prepared using geographic information systems. Finally, combined with variable selection and ecoregion map. Calculation of the characterization factors for each of these factors using geographic information systems, and characterization factors were obtained from the sum of the factors, a total characterization factor. Results indicated that there is the greatest sensitivity 5 ecoregion (dry/Astragalus adscendens Boiss) with characterization factors 1.29 and the lowest sensitivity to desertification 1 ecoregion (dry sub humid/Quercus brantii) with characterization factors 0.29. The results showed that aridity with 2.69 value, is the most effective factors to increasing the sensitivity of the area to desertification. Therefore, should pay attention serious to this problem in planning, managing and Combating desertification.

High temperature, high irradiance, low water vapour pressure, and lack of precipitation in most months characterize arid ecosystems. Under these conditions, trees such as pistachio suffer drought combined with salinity stress. In order to study the simultaneous effects of salinity and drought stresses on photosynthetic apparatus function in P. khinjuk, seedlings of the species were exposed to osmotic stress induced by a combination of salt and poly ethylene glycol (Ctrl (without any treatment), low osmotic stress (LOS), moderate osmotic stress (MOS) and high osmotic stress (HOS). Chlorophyll fluorescence yields were measured / calculated for the following parameters: F0, Fm, Fv, Fʹm, Fʹ0, Fʹm, Fʹv, Fs, F0 /Fm, Fv/ Fm, Fv/F0, Fʹv /Fʹm, &PhiPSII, ETR and Photoinhib-PSII%. A one way ANOWA showed that all the mentioned parameters were differently reacted to osmotic stress treatments without any visible symptoms of foliar phytotoxicity. The highest decrements or functional alterations in fluorescence parameters (in frame of defense mechanism or inactivation of photosynthetic apparatus) were observed at HOS.

Soil erosion by water and wind processes are carried out widely. So one of the best ways to estimate soil loss and land degradation is regional erodibility model. The aim of this research is codification regional erodibility model by statistical methods, the relation survey in Khoor and Biabanak between physical properties of soils and remote sensing indices. Sampling Method field was linear transect method and picked up 33 soil samples from depths of 0 to 50 cm. By transferring the samples to the laboratory, were calculated the elements of sand, clay, silt, organic matter and carbon, and then measurement erodibility values using the K-factor and SEI index. Then, was taken OLI sensor image accordance time sampling from USGS website. And were extracted the indices by enforcing functions the amount of Clay, NDVI, GOSAVI, SAVI, TSAVI, NDSI, SCI and GSAVI. Finally, were calculated using Pearson correlation between physical elements and soil erodibility with Remote sensing indices. At the end of for modeling SEI and K, through simple and multiple regression attempts to gauge the relationship between these parameters and selected best models from among with higher preference value. The results of modeling SEI represents the maximum linear correlation with the indices SAVI, NDVI and TSAVI respectively, with coefficient of 0.69, 0.66 and 0.63, and K factor linear correlation with the indices NDSI, SAVI and SCI, respectively, with a coefficient of determination 0.63 0.61 and 0.58 is at level 99%. Multiple regression analysis also showed a high correlation with group consensus SEI, K and Remote Sensing indices, respectively, with a coefficient of determination 0.517 and 0.564 and estimated error 0.0031144 and 0.0092369 at level 99%. Therefore, can estimate the amount of soil erodibility by remote sensing indices and univariate and multivariate statistical models. Which enables fast and precise estimation of SEI and K values in the Khoor and Biabanak region.