فهرست مطالب

Environmental Resources Research - Volume:2 Issue: 2, Winter - Spring 2014

Journal of Environmental Resources Research
Volume:2 Issue: 2, Winter - Spring 2014

  • تاریخ انتشار: 1394/02/01
  • تعداد عناوین: 7
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  • H.R. Asgari Pages 95-106
    Soil is accounted as a large sink for the atmospheric carbon dioxide. Carbon dioxide emission from soil will increase by operations such as land-use change, biomass and fuel combustion, industrial production as well as tillage. Operations like tillage could accordingly intensify the soil biological activity, which per se leads to more carbon emission to atmosphere. Thus, utilizing the methods ofseedbed preparation that cause low soil disturbances (conservation tillage) will prevent carbon emissions from the soil to the atmosphere; that in turn increases the content of soil organic matter; consequently, soil aggregate stability improves, against erosive factors. The research aims to assess the effects of different tillage systems (no-tillage, low tillage and conventional tillage) on the organic accumulation and the aggregate stability of the soil. The appropriate soil management and farming practices could exert a great positive influence upon crop yield. The study area is located in the eastern of Aq Qala, Iran. Three treatments of tillage systems, namely, traditional management, no-tillage and low tillagehave been examined in the study area in three replicates, based on therandomized complete block design (RCB). In each tillage system, 10 soil samples of about 0.5 kg (wet) weight for each sample (totally 30 soil samples) were taken from two soil depths (0-25 and 25-40 cm) using a 4 cm diameter Edelman auger. Some physicochemical properties of soil such as total soil organic matter, soil texture, bulk density, and mean weight diameter were measured. Tillage systems did not have any positive effects on soil organic matter (SOM) at two different soil depths (0-25 and 25-40 cm). However, the results showed that no-till system significantly (P>0.05) increased the SOM content of the total measured soil layer (0-40 cm) in comparison with other tillage systems. There is no significant difference in the effects of soil tillage managements onsoil bulk density. Moreover, all these three soil tillage systems caused nonsignificant change on soil aggregate stability against erosive factors.
    Keywords: Tillage systems, conservation tillage, physicochemical properties, soil, Aq Qala.1
  • D. Akhzari, M. Pessarakli, K. Shayesteh, M. Bashir Gonbad Pages 123-132
    Dust storm is one of the main global challenges that is more serious in the Middle- East. This phenomenon causes a lot of environmental and socioeconomic problems in Iran and several other Middle-Eastern countries. A Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used for trajectory analysis in order to reconstruct the origins of air masses in dust storms over several cities in the Western Parts of Iran. Backward trajectories analysis by HYSPLIT model showed that the main source of two occurrences of dust storms over several Iranian western cities has been originated from Syria passing through Iraq and arriving at the Western part of Iran. The Moderate Resolution Imaging Spectroradiometer (MODIS) images was used to monitor the monthly vegetation changes in the dust storm source areas. The Enhanced Vegetation Index (EVI) was obtained from recent MODIS vegetation data (2002-2009). Results revealed that source areas anthropogenic activities that reduced vegetation cover and activated wind erosion caused EVI numerical value reduction and dust storms occurrence over several Iranian Western cities.
    Keywords: Dust storm, HYSPLIT, MODIS, EVI1
  • M. Felegari, A. Talebi, M.T. Dastorani, A.S. Rangavar Pages 133-146
    Computer simulation models are becoming increasingly popular for predicting soil loss through quantification of the processes of detachment, transport and deposition of eroded soils. To assess the effects of different management practices on soil erosion and to select the best management practices, application of models (especially process-oriented models) and their validation is considered a positive step. In this research, the Rangeland Hydrology and Erosion Model (RHEM) was evaluated using soil erosion measuring plots and the recorded rain in Sangane Research Station, Khorasan Razavi Province of Iran. The model was run and the predicted runoff and sediment yield values were compared with measured runoff and sediment yield values. Then sensitivity analysis and calibration were done on sensitive parameters and model was run with calibrated parameters. In the calibration period the, the model efficiency (ENS) values and the coefficient of determination (r2) were 0.92 and 0.95 for sediment, and 0.60 and 0.70 for runoff, respectively. In validation period, the (ENS) values and (r2) values in 99% Confidence level were 0.70 and 0.84 for sediment and 0.11 and 0.65 for runoff, respectively. Our research indicated that the results of model were acceptable in 99% confidence level for sediment and could be used withreasonable confidence for soil loss quantification in the Sangane watershed and the other rangeland watershed with similar condition.
    Keywords: Hillslope Erosion, Rangeland Hydrology, Runoff, RHEM, Sensitivity analysis, Sangane
  • C. Funk, A. Salmanmahiny, G. Husak Pages 147-166
    The aim of this study is large scale environmental assessment and ecosystem degradation management in Ethiopia. To achieve this aim, eight years (2001-2008) of 500 meter MODIS Collection 5 global land cover type classification maps of the International Geosphere-Biosphere Programme (IGBP) were used to assess land cover changes in Ethiopia. Based on detailed assessment of the data and our aim, we chose nine out of a possible 54 land cover type transitions for modelling ecosystem degradation. We tested biophysical, imaged-based, climatic and surrogate socio-economic independent variables to model the nine transitions that were grouped into categories of worsening and improving ecosystem trends. Separate logistic regression analyses were successfully conducted for the transition modelling. The changes were then predicted in an integrated dynamic way for the year 2013 to provide a basis for examining trends in ecosystem condition. Proximity to roads, main towns and urban areas and villages, and distance to croplandsand barren lands were the most influential variables in the changing cover types. These variables are also directly manageable for controlling the downgrading trends in the country. The study provided a paradigm for further in depth studies and was linked with available results on climate assessment. Thus, the results can be joined to scenarios of climate and socio-economic changes to provide a platform for informed attempts in reversing the unwanted trends in land use/cover changes in Ethiopia.
    Keywords: Land Use, Cover Change, Modeling, Ecosystem Downgrading 1
  • S.H. Mirkarimi, C. Arrowsmith Pages 167-184
    The natural characteristics of protected areas change for a variety of reasons. These changes can be studied both spatially and temporally. Spatially, protected area landscape structures such as shape, size and location with respect to their neighbourhood context can be studied to describe landscape configuration. Temporally, landscape functions such as different geographical locations and land characteristics can be studied to determine the rate of temporal changes in landscape. This paper will introduce a developed framework to enhance the landscape ecological planning approach with attention to changes in landscapes of protected areas. Considering landscape ecological concepts, this framework draws upon spatial and temporal characteristics of protected areas. In order to examine the model in the real world, the data requirements for landscape ecological planning including a number of spatial and temporal metrics were implemented usinga case study method. The case study approach proved that spatial and temporal metrics can be used in the interpretation of spatial configuration and temporal variability of protected areas. A list of spatial and temporal criteria was developed to assist interpretation of area compaction, spatialfragmentation and temporal variability of protected areas. Using the criteria list, a new framework for spatial and temporal evaluation of protected areas has been developed. The results were used to determine spatial and temporal management issues of the case areas at the landscape scale. Then planning scenarios for spatial and temporal issues of the protected areas were suggested.
    Keywords: National park, protected area, protected area management, protected area planning, spatial, temporal metrics, landscape ecological planning1
  • M. Rahmati, M.R. Neyshabouri, S.B. Mousavi Pages 185-194
    One of the Arya and Paris model (AP) drawbacks is setting saturated water content (θs) equal to total porosity (f=1-ρb/ρp), in which ρb and ρp are soil bulk and particle densities, respectively. For swelled soils with θs greater than f, using AP model leads to under prediction of water content at the measured suction values. The aim of this study was to introduce swelling bulk density (ρbs,: defined as the ratio of dry soil weight to its swelled volume) and its application in AP model to improve model efficiency for swelling soils. For this, we used 22 soil samples to check the accuracy of the model after improvement. Application of the ρbs improved the accuracy of the model compared to the conventional ρb. Employing ρbs instead of ρb increased the R2 between measured and predicted water contents from 0.740 to 0.790 with a constant a 0.648 and 0.699 for variable a. Moreover, the intercept and slope of the regression line approached to 0 and 1, respectively.
    Keywords: Arya, Paris model, swelling soil, swelling bulk density