فهرست مطالب

Desert - Volume:21 Issue: 1, Winter - Spring 2016

Desert
Volume:21 Issue: 1, Winter - Spring 2016

  • تاریخ انتشار: 1395/06/02
  • تعداد عناوین: 10
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  • Andrew Goudie*, P. Kent, H. Viles Pages 1-13
    In northern Kazakhstan and neighbouring parts of the West Siberian Plain of Russia is one of the world’s biggest concentrations of pans. The area has thousands of them. Landsat imagery and Google Earth images indicate their distribution within this semi-arid area and their forms and associated lunette dunes. Many of the pans, most of which are small, wet and shallow, show a characteristic shape and orientation and some have developed in Pleistocene dune fields. Others have developed in old river channels and from the deflation of lake floors. The pans are in a low-relief area developed on Palaeogene, Neogene and Quaternary beds and have been shaped by winds coming from the south west. They occur in an area which is predominantly steppe grassland. Comparisons can be made with other global pan areas in terms of their number, densities, areas, and depths and in terms of the materials on which they have developed, and the climatic conditions that occur here they are found.
    Keywords: Pans, Wind erosion, Kazakhstan steppes, West Siberian Plain
  • Sajad Zareie, Hassan Khosravi *, Azam Abolhasani Pages 14-23
    The study of the groundwater resources and their properties are very important due to the vast desert areas and arid conditions. Given the current situation in Iran, the water supply is one of the most important territorial and environmental problems. In this study, groundwater resources were surveyed and mapped in Yazd Province and their properties were modeled to determine their effectiveness for grazing and agricultural activities. The main objective of this study was to develop and establish groundwater geoinformatics and cartographic monitoring of the meteorological data and groundwater formation. Also, the climatic characteristics were evaluated as determinants parameters of groundwater flow to measure its parameters variations. The thematic charts and geoinformatics maps were provided. Profile software was used for modeling microclimate and groundwater flow’s parameters, like groundwater level and moisture transfer for several decades. Priznak model was used for comparison and multi-parameter analysis of specified profiles and their classification. Finally, different regions of Yazd Province were mapped and classified with different degrees of possibility for grazing and agricultural activities. Results showed that groundwater levels in the study territory are at depths ranging from 40 to 145 m. According to the results, it was observed that the changes in groundwater level and microclimate can be used to evaluate the land capability for grazing and agricultural activities.
    Keywords: Yazd, Profile Software, Priznak, Groundwater, Modeling
  • Mohammad Golshan, Afshin Jahanshahi, Ali Afzali* Pages 24-34
    Development of rural areas in rivers margins and flood plains, without understanding and attention to the dynamical and hydrological conditions and upstream areas of the rivers will cause to increase flood risk and loss of life and financial. Flood zoning has many applications, in floodplain management. For management of the three major branches of the Halilrood River, Rabor, Roodar and Javaran in Safarood watershed in Kerman Province, flood hazard zonation was considered in this research. For this purpose, Flood levels in 2 to 200 return periods in three mentioned reaches (72.13 km) using HEC-RAS and HEC-GeoRAS extension were determined in GIS environment. Initially, Rivers Plan was divided to 163 cross sections and in 75 of them, hydrological data were collected and roughness coefficient was determined by Manning method. Results showed that 90.26 percent of the total area affected by the 200-year flood, Susceptible to flooding by the flood under 25 years as well as study on flood depth in the floodplain showed that 68.26 percent of the average depth of floods with 200 years return period is belonged to floods with under 25 year return period. Survey on roughness coefficient in the return period of 200 years, revealed that with a doubling of the roughness coefficient, area under flood 7.15 percent increase which proves direct relationship between the return period and flood area. The result confirms accuracy of combination geographic information system and HEC-RAS software in flood zoning and river modeling.
    Keywords: Zoning, Flood, Manning coefficient, Halilrood
  • Abolfazl Ranjbar* Pages 35-41
    Smirnovia iranica, a native valuable woody species from Fabaceae, is an adaptable plant of central sandy areas of Iran. Changes in chlorophyll fluorescence and photosynthetic pigments characteristics were analyzed in the course of phenological stages including vegetative, flowering, seed ripening, and seed falling stages, respectively (VS, FS, SRS, and SFS). The results obtained from analysis of variance indicated that there was a significant difference among different phonological stages of S. iranica in terms of the mentioned characteristics. Extending phenological stages along with increasing water deficiency resulted in significant reduction in Fv /Fm ratio in SRS and SFS. A significant effect of progression in phenological stages on thermal dissipation of light energy (D) value was observed in SRS and reached to the highest value in SFS. In all evaluated plants, during phenological development, there were decreases in photochemical efficiency of photosystem II (ΦPSII), and from SRS. A similar influence of the extending phenological stages on ΦPSII was observed for electron transport rate (ETR). In SRS to SFS, the decrease of Chl. (a) and Car was paralleled with the decrease of Fv/Fm, which indicated that pigments breakdown was accompanied by the decreasing of the maximum photochemical efficiency. The results of this study suggest that extending phenological stages along with increasing water deficiency stress resulted in significant alterations in chlorophyll fluorescence parameters and pigment contents in SRS and SFS.
    Keywords: Electron transport rate, Phenology, Photosynthetic apparatus, Pigment, Quantum yield
  • Zahra Alibakhshi *, Marziyeh Alikhah Asl, Mohammad Rezavani, Mohammad Namdar Pages 42-48
    Miqan desert wetland is one of the 10 major wetlands in Iran. In 2008, it has changed into a non-hunting area due to its fragile ecology. Evaluating the change trends of the wetland and the use of its surrounding lands is of high significant in order to maintain the wetlands. In this regard, the satellite images of the ETM and OLI sensors of years 2002 and 2013 were initially collected. After performing atmospheric and geometrical correction operation through using the instructed samples derived from Maximum Likelihood Classification Method, they were classified into five different classes namely wetlands, barren lands, grasslands, dry-land farming and irrigated farming. The results indicate the overall accuracy of 80.20 and 84.91 for image classification in 2002 and 2013, respectively.The most significant changes observed were an increase of water level water from 7784.57 hectares in 2002 to 7887.35 hectares in 2013 for wetlands; however, the long-term average annual rainfall in recent years shows a 26-percent reduction. Accordingly, the reason of this 0.26-percent increase of the wetland water level can be attributed to the flow of water from the wastewater treatment center. An increase 20% in the dry land farming, and the 12% reduction of grasslands, 0.31% irrigated farming as well as 8.27% barren lands. The main reasons for such changes include setting a sewage refinery in one of the wetland entrances, conversion of grasslands into dry land farming, recent droughts, and growing salinity-tolerant plants such as Nitraria Schoberi.
    Keywords: Miqan Wetland, Changes, Remote Sensing
  • Hossein Sadeghi *, Laleh Rostami Pages 49-55
    In order to investigate the effect of drought and salinity stress on caper plant (Capparis spinosa), a factorial experiment including two factors consisting of drought and salinity levels based on randomized complete block design (RCBD) with five blocks were carried out at College of Agriculture, Shiraz University, Shiraz, Iran. After pretreatment, seeds were germinated in petri dishes and then transported to pots, to grow out of the glasshouse under natural conditions (same as environmental condition). Measuring morphological (Plant height, number of leaves, length of greatest leaf, root length, shoot fresh weight, shoot dry weight, root fresh weight and root dry weight, and chlorophyll (pad) and also physiological traits (relative water content (RWC) and water saturated deficit (WSD) for both root and shoot, root water content (RooWC) and leaf water content (LWC) showed that salinity and drought stresses as well as ABA concentration had negative effects on the plant. ABA content was significantly higher in salt-treated plants than in drought treated ones. The injury effect of salt stress was lower than drought. The results also indicated that the changes in response to the two stresses were low and so that this plant could be a suitable candidate for sowing and using in arid and semi-arid regions and also in saline condition.
    Keywords: Chlorophyll, ABA, Arid regions, Root dry weight, Drought
  • Rohollah Rezaei *, Ehsan Gholifar, Leila Safa Pages 56-64
    The main purpose of this study was to identify and explain the effects of drought in rural areas of Iran. The statis­tical population of this study consisted of all the heads of households of Esfejin village in Zanjan County (N = 2932). A sample of 340 persons was selected using a method of simple random sampling. Data were collected from face-to-face interviews with respondents based on a structured questionnaire. A pilot study was conducted to establish reliability of the questionnaire. Cronbach's alpha coefficient was used for the main scale of questionnaire, which scored more than 0.75, confirming its appropriate reliability. The results revealed that four factors can be considered as important for identifying and explaining the effects of drought in Esfejin village and these factors were economic, environmental, social and psychological. The findings of this study contribute to a better understanding of the effects of drought in rural areas and can be implemented in future planning of proper programs to overcome these effects.
    Keywords: Drought, Effects, Zanjan County, Iran
  • Nasim Safari, Fatemeh Kazemi * Pages 65-75
    Green space is one of the important infrastructures for keeping natural life and sustainability in modern urbanism and it provides excellent recreational opportunities for the people in the society. However, there are limiting factors in green space development, especially in arid regions, including extreme weather and soil temperatures, low average rainfall, drought, and high potential for evapotranspiration. Therefore, sustainable green space development, especially in these regions, should seek strategies and landscape materials to tackle these limitations. Some green space materials, which have been argued to address such limitations, are mulches; but still potentials of these materials in urban green space development have not been well discussed. This study reviewed scientific literature in order to discuss how non-living mulches and cover plants as living mulches can assist in the development of green spaces in arid regions. It aimed to introduce mulches and cover plants and compare their environmental, ecological, functional, and aesthetic potentials. According to the results, cover plants and non-living mulches can maintain visual aesthetics while they can also have environmental benefits, such as reducing water consumption, weeds and soil erosion as well as adjusting soil moisture and temperature in urban green spaces. High diversity of cover plants is one of the most important and practical features for green space development. This paper also identified that, despite significant benefits listed for using these materials in urban green space, their application in green space design and construction of many countries, such as Iran, is still less considered.
    Keywords: Cover plant, Mulch, Organic, Sustainable, Urban green space
  • Seyed Mohsen Mirhosseini, Ali Akbar Jamali, Seyed Zeynalabedin Hosseini * Pages 76-90
    In the present study, in order to calculate the movement of sand dunes in the period between 2001 and 2010, the ASTER (Advanced Space-borne Thermal Emission and Reflection Radiometer) images were used. The training samples were obtained from the field, and the images of the years 2001 and 2010 were classified using maximum likelihood algorithm and decision making tree. The study area was classified into four classes, including vegetated areas, urban areas, sand dunes, and bare lands. Accuracy of the created land cover maps was assessed using five hundred ground control points, Google Earth, and Landsat 7 satellite images. Based on the results, the overall accuracy and kappa coefficient for the maps of 2001 and 2010 were estimated 96%, 0.94 and 98%, 0.98, respectively. In the next step, the resulted land cover maps were used as input for Land Change Modeler (LCM) and Markov calculation. Statistical outputs and change map of this model show the extensive changes in the dunes during the study period. In addition, the area of sand dunes increased from 12,103 to 14,355 hectares. However, 6 hectares of vegetated areas around the Ashkezar and Zarch cities in the North West of Yazd changed to sand dunes. The highest probability of change in the dunes is the change of dunes to bare lands and the lowest probability is the change of dunes to vegetation lands. These results show the movement and change of the dunes in this arid zone.
    Keywords: ASTER image, Dune, Land change modeler, Markov, Prediction
  • Hossein Shekofteh*, Nava Salari Pages 91-101
    To evaluate the effects of hydrogel polymer levels (0, 10, 20, 30 g m-2) and NO3:NH4 ratios (0: 100, 25: 75, 50: 50, 75: 25, and 100: 0) on dill seed yield and its essential oil constituents, an experiment was conducted in October 2012 in the experimental field of Islamic Azad University, Jiroft, Iran. Results showed that using 30 g m-2 hydrogel polymer with 75NO3-: 25 NH4 ratio produced maximum seed yield and the same plus 100NO3-:0NH4 led to a max essential oil yield. GC-MS analysis indicated that major constituents of dill seed oil were carvone, limonene, dillapiole, α-phellandrene, and trans-dihydrocarvone. The interactive effects of concurrent use of hydrogel polymer and NO3-:NH4 ratios on the constituents were evaluated: non-use of super-absorbent polymer reduced components like α-terpinene, limonene, dillapiol, and trans-carvone, whereas its addition to such compounds as α-phellandrene, p-cymene, carvone, and trans-dihydrocarvone left a negative effect. In most cases, application of nitrate above 50℅ and reducing ammonium positively increased the compounds.
    Keywords: Medicinal plant, Nitrogen, Nutrition, Iran, Water