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Desert - Volume:22 Issue: 1, Winter - Spring 2017

Desert
Volume:22 Issue: 1, Winter - Spring 2017

  • تاریخ انتشار: 1396/04/24
  • تعداد عناوین: 11
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  • M. Maghsoudi, A. Hajizadeh, M.A. Nezammahalleh *, Z. Bayati Sedaghat Pages 11-19
    This research has attempted to measure the parameters of barchan dunes as one of the desert landforms. This has been conducted by a field survey using cartographic techniques. In the field, two barchan dunes have completely been surveyed by total station equipment. Using the sample points a novel method has been devised to measure the barchans parameters.
    The method is mainly based on geometric relations and Cartesian coordinate system. All the parameters of the dunes have been measured by both the common methods of previous studies and the new method of this study. By this research, some new parameters have also been added to the dune analysis studies. The method has proved to be more precise relative to the previous methods for measurements of barchans. These measurements make it possible to compare the dunes in different areas of the world and also for different periods of time. Many parameters of the dunes can also be examined more easily.
    Keywords: barchan, Surveying, Sand dune, Lut Desert
  • M. Ghodsi * Pages 21-29
    Yardangs are one of the most amazing geomorphic features of Lut desert, Iran developed in alluvial deposits of Pleistocene. They appear as the streamlined hills that are separated by U-shaped troughs with a flat-topped. The study of yardang’s morphometric parameters is important to define their morphological indices. In This study, we describe the morphology of yardangs in the Lut playa, analyze the wind factor, and discuss their development processes. Up to 132 yardangs have been identified and measured by linear sampling method along 9 transects (with 10 km length) located on digital elevation model (10×10 m) in the Global Mapper software. The obtained results of simple regression showed the central and the northern areas have the maximum correlation respectively between the width and length of yardangs. The length-to-width ratio is close to 3.5:1. The yardangs size and height in the center and north of the region are more than the southern side. This represents further evolution of yardangs where exist in the south and side of region. Wind and water erosion plays a particularly important role in this process.
    Keywords: Lut Desert, Iran, Winddeflation, Yardangs, Gemorphometry
  • U. Egwu, Y. Hoseini * Pages 31-42
    This research investigate clayey, lateritic and sandy soils have been selected from agricultural lands in the South-Eastern Nigeria, for their phosphate sorption characteristics using column experiments, in order ascertain the movement of phosphate in the soils. The soil samples were equilibrated in 25ml of 0.01M CaCl2 containing different concentrations of P as KH2PO4 to produce initial concentrations of 250, 375, 500, 625 and 750µg/L of P for 14 days at room temperature. Six samples and a backup treatment were prepared for each concentration for each soil sample giving a total of 25 samples of each soil. Fitting the adsorption results from all the soil tested into Freundlich, Langmuir and Van Huay linear isotherms revealed that the adsorption of phosphate increased with the concentration of P and contact time. Values of P sorption maximum (Smax) for all the soils were obtained in day 10 and were 12, 15 and 12 mg/kg soil for clayey, lateritic and sandy soil respectively. The higher sorption of lateritic over clayey soil was due to its high content of clay and clay minerals. The Freundlich isotherm perfectly fitted the clayey soil with the highest accuracy than the Langmuir and Van Huay isotherms, and also gave better description of the lateritic soil but did not adequately describe the sandy soil like the other isotherms. Comparison of the three isotherms showed that the Freundlich isotherm was the best for predicting the phosphorus adsorption behaviour in soils. The leaching of P in the soil column experiment was time-depth dependent and therefore, the use of slow phosphate fertilizer and lime could improve p-adsorption on the soil.
    Keywords: Phosphate movement, Soil, Sorption experiment, column experiment, Isotherm
  • Assessment of desertification hazard, risk and development of management plans
    S.A. Arami *, M. Ownagh Pages 51-67
    About 80 percent of Iran is arid and semi-arid and about 35 percent of this area is susceptible to desertification hazard. Therefore desertification assessment and identification of the most important criteria for the assessment of risk and a basis for development of management plans is essential. This research was conducted in the semi-arid region of Agh-Band in the Golestan province, Iran with an area of 3062.5 km2 aiming at preparation of the desertification hazard and risk maps and development of various management plans to control the desertification. In this study, the IMDPA model and geomorphologic facies were used to evaluate the desertification hazard. The work units (geomorphologic facies) were defined based on geology and land use maps, satellite images and field surveys. The risk map was developed with a combination of desertification hazard intensity and hazard elements [A1] [A2] and degree of vulnerability maps using the total risk equation. Desertification management plan was developed based on four management strategies including: no plan, maintains the status quo, avoid the risk and implement the control measures. The results indicated that soil and vegetation criteria with magnitudes of 2.67 and 2.54 fall into sever desertification category (III) and other criteria are within medium class (II). The average value of degree of desertification in the study area was 2.03 (class II).
    Keywords: Desertification hazard_Geomorphologic facies_Risk_Management Plan_Agh - Band_Golestan
  • K. Rezaei Tavabe *, A. Malekian, A. Afzali, A. Taya Pages 69-75
    Fresh Water Rivers are one of the most important aquatic ecosystems in arid and semi-arid regions of Iran in point of biodiversity and drinking water views. Damghanroud River is one of these rivers at Semnan province that during past years has been threatened by drought and anthropogenic pollutions. This river supplies some parts of drinking water of Damghan city and some vicinity villages. The aim of the present study is to consider Biological Index of the river; for this purpose, limnological and hydrobiological studies of the river were carried out. At this study, seven sampling stations were determined based on limnological standard method along the river; afterwards sampling of invertebrates (Biological Index) and water quality (BOD) were performed seasonally during study period. The results showed that the first station (Cheshmeh-Ali) is free of pollution while the fourth sampling station (Doab) is the most polluted region at the river because the first station has no pollutant resource but the fourth station directly receives wastewater of agricultural activities and rural wastewaters. According to biomonitoring and water BOD measurement findings, Damghanroud River has relatively polluted situation and is classified in β-mezosaprobe class and benthos biological index has been deteriorated at this river.
    Keywords: Damghanroud river, Semnan Province, Biological index, Saproby, BOD
  • H. Khosravi *, F. Sajedi Hosseini, M. Nasrollahi, H.R. Gharechaee Pages 77-84
    The most important impacts of climate change relate to temperature and precipitation. Precipitation is particularly important, because changes in precipitation patterns may lead to floods or droughts in different areas. Also, precipitation is a major factor in agriculture and in recent years interest has increased in learning about precipitation variability for periods of months to annual and seasonal trends and change points had been analyzed for 22 rainfall stations in Fars province during 1972 to 2011. Mann-Kendall non-parametric test and Sen’s method had been used to determine positive or negative trends; also Pettitt test, Standard normal homogeneity test, Buishand range test, Von Neumann ratio, for detection of change points in the time series had been implemented. The TFPW approach had been used in order to decline the effects of autocorrelation and serial correlation on Mann-Kendall test. The results of Mann-Kendall test and Sen’s Method showed decreasing trend for all rainfall stations except for the Monje station. But, no significant trends were observed in all stations. Also, the results indicated that the precipitation has not occurred nonhomogeneity; whereas all test indicated there is no change point on precipitation time series. No change and abrupt shift were visible in the precipitation time series except in winter for Ali Abad Khafr; and Ali Abad Khafr; Tangab and Ramjerd based on pettitt test and Standard normal homogeneity test, respectively.
    Keywords: Fars Province, Mann-Kendall test, Pettitt test, Precipitation, Variability
  • A. Kouhpeima *, S. Feyznia, H. Ahmadi, A.R. Moghadamnia Pages 85-95
    Every year, hundreds of people all over the world lose their lives due to landslides. Landslide susceptibility map describes the likelihood or possibility of new landslides occurring in an area, and therefore helping to reduce future potential damages. The main purpose of this study is to provide landslide susceptibility map using logistic regression model at Latyan watershed, north Iran. In the first stage, 208 Landslide locations were identified and mapped using extensive field surveys. 75 % of these landslides were used for training and 25 % of them for validation of the model. The mapped landslides were then georeferenced using ArcGIS 10 to provide the landslide inventory map. In the second stage, maps of factors affecting the occurrence of landslides were prepared in ArcGIS 10. Finally in the last stage, the relationships between these affecting factors and the landslide inventory map were calculated using Logistic regression algorithm. The amount of pseudo R2 (0.32) and AUC (0.85) shown the high efficiency of Logistic regression model. According to the coefficients obtained by the model, lithology is the most important factor affecting landslide occurrence (coefficient= .032). Most landslides (69%) are located within Ek Formation. The results indicated that 7.56% of the basin is located in high susceptibility class and 2.88% in very high susceptibility class.
    Keywords: landslide, Logistic regression, Latyan catchment, PGA, Iran
  • The impacts of different land use changes on groundwater level using quantitative model WEAP (Case study: Chaharmahal Bakhtiari province, Iran)
    G. Mortezaii Frizhandi * Pages 97-105
    Reduction of water resources limits the ability of farmers for food production and subsistence. Nowadays the quick growth of population has been the most important factor in the decline of renewable water. In many parts of Iran, including region of interest, the major factor in water resources decline was land use change, that may cause to ecological destruction and disruption. Sustainable development can be achieved with proper management of watersheds. This study tried to determine the effect of land use type on water resources the ChaharmahalBakhtiari plains. TM images in May of 1982, 2000 and 2012 were used to prepare the land use maps for 8 plains. The resulted maps for 2012 were reviewed using topographical maps (1:25000) and field observations. The water level measurements during 2002 to 2012 in different plains were used for calibration and validation of WEAP model. The quantitative model used to determine the effects of land use changes on groundwater level. The extent of Agricultural land use have increased from 1982 to 2002 and 2012 from 28.8% to 35.6% and 38.7% accordingly. The results revealed that except of Farsan, Shalamzar and Gandoman the other plains have negative groundwater balance. The model simulation showed that continuing the current harvesting cause to critical situation in the near future. To compensate the negative water balance of Shahreh Kord, Borojen, Sefid dasht, Kiyar, Flared and Khan mirza, it would be necessary to reduce the consumption of groundwater resources of these plains up to %48, %32, %66, %30, %13 and %12, respectively. The change of land use from grasslands to agriculture was the main reason of reduced the groundwater reserves.
    Keywords: Rangeland, land use, WEAP models, satellite imagery, Chaharmahal Bakhtiari
  • S. Delshadi, M. Ebrahimi *, E. Shirmohammadi Pages 107-116
    Drought stress is one of the most important factors affecting plant growth. Plant growth under drought stress may be enhanced by the application of microbial inoculation including plant growth promoting rhizobacteria. This research was conducted as a factorial experiment in a completely randomized design. The first factor included the bio-fertilizer (A. vinelandii (A)), P. agglomerans P. putida stroin (P), A P and control (without bio-fertilizer). The second factor was drought stress at three levels of field capacity (FC), 0.7 FC and 0.4 FC. The results showed that treatment A P at FC level had the highest effect on increasing photosynthetic pigments (p
    Keywords: Azotobacter, Pseudomona, Chlorophyll contents, environmental stress, plant growth
  • Z. Saeedavi, B. Khalili Moghadam *, M. Bagheri Bodaghabadi, N. Rangzan Pages 117-133
    Soil is a vital parameter for planting design in urban green spaces especially in adverse climate conditions. In this study, the utilization of analytic hierarchy process (AHP) in surveying land suitability for urban green space from measured criteria like suitability indices, including physical (i.e. clay, silt, sand, bulk density, penetration resistance), chemical (i.e. electrical conductivity, sodium absorption ratio, organic matter, Olsen phosphorus, water soluble potassium and DTPA-extractable of Fe, Zn, Cu, Mn) and heavy metal (i.e. total Ni, Cd and Pb) properties of soil and topography attributes (i.e. slope degree) data were investigated. The subjective value judgment, in light of questionnaire survey was utilized for pair-wise comparison after standard AHP method in a structure of four criteria (suitability indices) alongside related sub-criteria (19 factors). AHP method and GIS techniques were combined to create suitability map. The outcomes demonstrated that less than 8.86% of the all study region has no restriction and 34.54% has extreme restrictions for green space land use. The southern part of the riverside parks had higher suitability, whereas the northern area had lower suitability. The real limiting variables include soil compaction, soil salinity, and Zn deficiency; albeit direct mild accumulations were for lead in Ahvaz riverside parks. This study delineates the efficacy of AHP and weighted overlay model for the soil suitability investigation of green space in the study territory. In light of the outcomes, bulk density and organic matter are the most vital indices of soil in urban green space.
    Keywords: Urban soil, Green spaces, AHP, GIS, Ahvaz
  • I. Esfandiarpour *, M. Ranjbar Khorasani, H. Shirani Pages 135-143
    The main purpose of the current research is comparing the results of Artificial Neural Network (ANN) with Adaptive Neuro-Fuzzy Inference System (ANFIS) with regard to determination of the importance of soil properties affecting clay dispersibility. After taking samples from two depths of 0-40 and 40-80 cm, the spontaneous and mechanical dispersions of clay were recorded using both weighing and turbidimetric methods. To determine the degree of importance of soil properties affecting clay dispersibility, first ANNs and ANFIS in MATLAB Software were determined, using all research variables. After determining less effective properties and omitting them, the mentioned networks with the remaining variables including percentage of clay and sand, soil reaction, Electrical Conductivity (EC) and Sodium Adsorption Ratio (SAR) were measured and the degree of importance of each variable in clay dispersibility was determined. Finally, the results of ANNs and ANFIS were compared by calculation of validation parameters. Existence of high correlation between calculated values for weighing and turbidimetric methods showed a linear relationship between the two methods. In general, in both depths and for both weighing and turbidimetric methods, the sensitivity of clay dispersibility to the percentage of the clay, sand and SAR, was higher than any other variable. Although the results obtained from the validation statistics indicate high accuracy of both ANN and ANFIS models, the last model showed relatively better results as compared to ANN model.
    Keywords: Arid regions, dispersible clay, Land Degradation, Neuro-fuzzy models, Sodic soils