فهرست مطالب

  • Volume:7 Issue:4, 2019
  • تاریخ انتشار: 1398/06/10
  • تعداد عناوین: 7
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  • M. Hayatzadeh*, A. Fathzadeh, V. Moosavi Pages 183-193

    Mapping of Land use/cover is important for many activities of planning and management, especially in arid areas. Nowadays, satellite imagery and remote sensing techniques, which provide timely and high capability data, are widely used in producing this kind of mapping. The main objective of this study is to produce an actual land use map using advanced pixel-based (MLP, SVM, and SOM) approaches. The most important challenge, in this case, is to determine the optimum structure of classification methods. The Taguchi method is used to optimize the structure of MLP, SVM, and SOM methods. Results show that the Taguchi method can be effectively used to cope with this problem. It significantly reduces the number of classification tests. We also showed that there are significant differences between the results of the SVM method with those of the MLP and SOM methods (χ2 more than 100) and that SVM model is more efficient than other methods. The accurate map produced by the optimized SVM approach (Overall accuracy of 0.93) showed that this method has a better performance.

    Keywords: Land Use, Cover Map, Taguchi Method, Optimization, Pixel-Based Classification
  • M. Moudi*, M.S. Hosseinzadeh Pages 195-201
    Aims

    Species distribution models (SDMs) are predictive models for species’ geographic distributions which are in association with environmental factors and presence of species. SDMs are important for a variety of applications in systematics, ecology, and conservation. The genus Ziziphus Mill. (Rhamnaceae) comprises six species in Iran including Z. spina-christi, Z. nummularia, Z. jujuba, Z. mauritiana, Z. lotus, and Z. oxyphylla. Out of which, Z. jujuba is a common species of the genus.

    Materials & Methods

    In this study, 43 occurrences of Ziziphus jujuba were recorded and used in the maximum entropy distribution modeling approach (MaxEnt) with five environmental variables. Three important variables: bio6 (Min Temperature of Coldest Month, 24.3%), bio8        (Mean Temperature of Wettest Quarter, 23%), bio9 (Mean Temperature of Driest Quarter, 20.5%) include 67.8% of all percentage contribution in the final model.

    Findings

    Slope, five temperate and two precipitation variables influenced our final model. The most suitable habitats are located in eastern Iran which completely corresponds to South Khorasan province and central Iran. Additionally, the species is distributed in northern Iran as well but our model doesn’t show northern Iran as the most suitable habitat for Z. jujuba which probably related to the species has been cultivated in that place.

    Conclusion

    Temperature is one of the most important factors in the distribution of Z. jujuba and it is compatible with that Jujube trees raise in arid and semiarid zones. However, the predictable habitats are distributed in central and eastern Iran which partly corresponds to South Khorasan province.

    Keywords: Species Distribution Model, Jujube, Temperature, South Khorasan, Environmental Factors
  • D. Akhzari*, A. Shayganfar Pages 203-210
    Aims

    Ferula L. is one of the largest genera from Apiaceae family with about 180 species, which grow in semi-arid rangelands. One of the challenges associated with this genus in their natural habitats is drought and additionally in case of Ferula haussknechtii H. Wolff ex Rech.f. species is allelopathy caused by companion with Artemisia persica Boiss.

    Materials & Methods

    The present study aimed to investigate the roles of Arbuscular Mycorrhizal (AM) fungi in the growth, physiological characteristics, nutrient uptake, and survival of Ferula haussknechtii H. Wolff ex Rech. F. grown under the interactive influences of drought and allelopathy stress conditions. Four levels of allelopathy stress, three levels of drought stress, and two mycorrhizal treatments (AM and Non-AM) were applied to the pots in a completely randomized design with a factorial arrangement.

    Findings

    Based on ANOVA results (p≤5%), the survival capacities of the Non-AM inoculated plants were significantly less than those of the AM inoculated plants for all allelopathic and drought stress levels. The maximum values of survival capacity were seen in AM×FC×A1 treatment as 75% and the lowest survival capacity was observed in Non-AM×30%FC×A4 as 29%. In general, AM fungi inoculation significantly increase the root:shoot ratios and mycorrhizal dependency values (p≤5%). Based on ANOVA results, the highest and lowest values for root:shoot ratios were observed as 0.71 and 0.27 for Non-AM×30%FC×A4 and AM×FC×A1 treatments, respectively. Drought stress and allelopathic conditions have a destructive effect on total chlorophyll content. The maximum and minimum proline content (0.21 and 0.04) was observed in treatment of AM incubated with highest level of drought and allelopathic and in Non-AM incubated with lowest level of drought and allelopathic, respectively.

    Conclusions

    AM fungi inoculation had a significant positive effect on total nitrogen and phosphorus content in plant tissues but a significant negative effect on total nitrogen and phosphorus content was observed in drought and allelopathic stress treatments.

    Keywords: Mycorrhizalinoculation, Allelopathy, Drought, Ferula haussknechtii, Artemisia persica
  • M. Yousefi Malekshah, R. Ghazavi*, S.J. Sadatinejad Pages 211-221
    Aims

    The aim of this study was to the prediction and analysis of temporal pattern changes of runoff, maximum discharge, and Drought indexes in the Tehran-Karaj basin.

    Materials & Methods

    In this study, the temperature and precipitation data extracted from Statistical Downscaling Model (SDSM; 2021-2050 and 2051-2080) together with observational runoff data of the Sulghan hydrometric station (1986-2015) were used as input data for IHACRES rainfall-runoff model and discharge rate, runoff volume, and maximum discharge were extracted in the desired scales. Then, drought indexes (SPEI and SRI) were investigated.

    Findings

    In the period of 2021-2050 and 2051-2080, the mean of annual discharge, volume of runoff and annual precipitation will be decreased. While seasonal runoff, discharge, and precipitation will rise in the winter. Moreover, the maximum predicted discharge (In most scenarios) in the return periods less than 5 and more than 50 years is less than the observation period and in the Return Periods of 5 to 50 years it will be more than the observation period. Besides, 48-month SPEI with 48-month SRI (without delay) has a maximum correlation with each other at the level of 99%.

    Conclusion

    In the winter season and return periods of 5 to 50 years, the floods hazards and Rivers overflow in the Future periods (2021-2080) will be more than the observation period. Also, meteorological droughts often have their effect on the drought of surface waters during the same month.

    Keywords: Climate Change, Statistical Downscaling Model, IHACRES, Maximum Flood Discharge
  • A. Pirali Zefrehei, M. Fallah*, S.A. Hedayati Pages 223-231
    Aims

    Monitoring and zoning of water resources are one of the important principles in environmental planning and management. Therefore, considering the issues raised and the importance of Anzali wetland monitoring, the assessment of effective factors in zoning (GIS) along with TSI p, TSI n, and NSFWQI indices and the study of land use effects justifies the necessity of this study.

    Materials & Methods

    In this study, physicochemical parameters of water (phosphate, total nitrogen and total dissolved solids, dissolved oxygen, acidity, electrical conductivity, and BOD5 properties) and water quality indicators (TSI p, TSI n, and NSFWQI) were modeled using GIS interpolation functions. To determine the effect of land use, the partial and Pearson correlations coefficient were used.

    Findings

    According to zonation maps of annual mean values of qualitative parameters, the lowest dissolved oxygen content was in the eastern part of the wetland, the highest electrical conductivity, as well as BOD5 observed in the center of the north, in the east and north of the wetland, respectively. A survey of the total phosphate zonation map revealed the increasing trend from west to east of the wetland. The partial correlation analysis showed that the electrical conductivity, acidity and total dissolved solids were directly affected by inputs and effluent from the land use (p<0.05; p<0.01).

    Conclusion

    Based on the coefficient of determination, about 70% of the pollution derived from the use of wetlands surrounding and entering wastewater from agricultural fields, industrial and urban.

    Keywords: Anzali Wetland, Partial Correlation, Buffer, Water Quality Index, Interpolation
  • F. Zafarshademan*, M. Ajorlo, M. Dahmardeh Ghaleno, M. Ebrahimian Pages 233-244
    Aims

    Accurate and timely estimates of the water balance are necessary for the maintenance of surface and underground waters. The purpose of the present study was to investigate effect of land use change on the water balance of Gharib Abad Watershed using the WetSpa model.

    Material & Methods

    The present study was carried out in Gharib Abad Watershed in Zahedan with a total area of 9924.4ha in Sistan and Baluchestan Province. Firstly, the model was implemented for the statistical period of 2008-2016 using the land use map of 2016, so that to calibrate the model, the statistical period of 2008-2012 and to validate the model the statistical period of 2012-2016 were selected. Then in order to investigate the effect of the land use change on water balance, all data and maps used in the model were maintained fixed (except for the land use map) and the model was simulated using the land use map of 2000.

    Findings

    In the land use of 2000 from total precipitation, the evaporation rate was 69.60%. In addition, 4.13% of the total precipitation was stopped and evaporated by vegetation cover. Moreover, 26.27% have been converted to runoff. While in the land use of 2016 the evaporation increased by 9.01%, the vegetation cover decreased by 2.42%, the runoff decreased by 6.59%. Also,  and  were identified as the most sensitive parameters.

    Conclusion

    The WetSpa mode has well estimated the components of the water balance of watershed and has the necessary efficiency in arid areas.

    Keywords: Simulation, Hydrograph, Hydrological Process, Vegetation
  • A. Parsakhoo* Pages 245-255
    Aims

    Fine grained soil shows weak geotechnical properties when they are used in roadbed. The aim of the present study was to assess the efficiency of nano-SiO2 and horsetail ash in improving the mechanical properties of high plastic cohesive soil (CH) and low plastic cohesive soil (CL).

    Materials & Methods

    Soil samples were brought from an earthy bed of proposed roads in Bahramnia Forest, Golestan Province, Iran. Then Atterberg limits, maximum dry density (MDD), unconfined compressive strength (UCS) and California bearing ratio (CBR) tests were conducted on the soil samples treated with 0.5% nano-SiO2+1% ash, 1% nano+2% ash, 1.5% nano+3% ash and 2% nano+4% ash. Analysis was done on 7, 14, and 28-day aged samples. Statistical analysis was done using the SAS 9.4 software to compare means among treatments.

    Findings

    Results showed that liquid limit and plastic limit increased to 56% and 37% for CH and 50% and 32% for CL with increasing the percentage of nano-SiO2 and ash mixture. These changes reduced the plastic index. With the increase in the percentage of additive materials and curing time, the MDD, UCS, and CBR get increases. Dry density decreased by increasing moisture content at the peak state (1.70g cm-3 for CH and 2.03g cm-3 for CL). The nanoash treated CL soil has a higher density than the nanoash treated CH soil.

    Conclusion

    A optimal mixture of 1.5% nano-SiO2+3% horsetail ash and 1% nano-SiO2+2% ash, as well as 28-day curing time, is recommended for the stabilization of CH and CL earthy bed, respectively.

    Keywords: Plant Ashes, Nanoparticles, Soil Strength, Atterberg limits, Roadbed