Desertification is one of the main environmental and also social and economic problems facing Iran. Seventeen out of 31 Iranian provinces, which are home to approximately 70% of the total population, are affected by desertification. This study aimed to use geographic information system (GIS) and fuzzy logic for mapping environmentally sensitive areas to desertification based on Mediterranean Desertification and Land Use approach in Isfahan province, central Iran. Six desertification indicators including climate, soil, vegetation, soil erosion, groundwater, and management and policy quality were used to determine various types of environmentally sensitive areas to desertification. Seventeen desertification indices affecting the quality of each indicator were spatially mapped and assigned a value between 0 and 1 using a fuzzy logic option of ArcSDM3 software in GIS environment. Results showed that a 21·7% of the study area was classified as critical, 70% as fragile and 5·5% as potential, and 2·9% of the area was not affected by desertification. In the town of Borkhar, 64·2% of the area was classified as critical, followed by the towns of Isfahan and Nayin with 40·2% and 31·8%, respectively. Results at provincial scale indicated that the climate indicator and humidity index with a weighting mean of 0·71 and 0·77 were the most affective factors in the desertification of the study area. The developed model in this study can be used for mapping desertification status in other 16 provinces that contain desert areas. These assessments provide a GIS-based desertification database that Iran as a member of the United Nation Convention to Combat Desertification can use to report the condition of desertification at national scale. Copyright © 2013 John Wiley & Sons, Ltd.

Quantitative Mapping and Assessment of Environmentally Sensitive Areas to Desertification in Central Iran

Wind erosion could be regarded as one of the most important phenomena especially in arid lands in the globe, which destroys vast areas with its rapid growth. Due to global droughts and climate change, vegetation is weakened and soil particles are more easily exposed to wind erosion. Today, various methods have been developed to control wind erosion. One of the most commonly used methods is the use of mulch. Mulch has several types (physical-chemical). The purpose of this research is to make organic mulch with inexpensive and available compounds to prevent environmental pollution as well as preventing wind erosion. For this purpose, Chaff, Manure, Biosolids and Black Strap mixture were used. The surface response method (RSM) was utilized to perform the relevant tests and create optimal situation. In this study, the central composite design (CCD) in RSM modeling was applied to make the optimal experimental conditions of erosion and penetration resistance. The effect of concentration of Chaff, Manure, Biosolids and Black Strap, was evaluated in erosion and penetration resistance and each variable was coded at five levels. The optimum values for penetration resistance of 1.8 (kg/cm2) for Chaff, Manure, Biosolids, and Black Strap, were 11.32, 15.72, 19.23 and 4.37 g, respectively. Also, the optimum values of mulch combination for wind erosion of 1.8 kg/cm2 for Chaff, Manure, Biosolids, and Black Strap, were 12.49, 19.95, 16.71 and 7.15 g, respectively. By increasing the use of these compounds, adhesion and erosion resistance increased and more consumption of Black Strap had a reverse effect. This was due to the loosing of soil particles and creating exponential mode in graphs. According to the results, no particular distinction was found between predicted data by Design-Expert software and experimental data and simulation results can be expressed reliably.

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Simultaneous optimization of parameters influencing organic mulch test using response surface methodology.

Monitoring desertification processes using ecological indicators and providing management programs in arid regions of Iran

South of the Zagros belt, the entire land of Southern Iran faces problems arising out of various types of land degradation of which water erosion forms a major type. A new model has been developed for assessing the risk of water erosion. Taking into consideration nine indicators of water erosion the model identifies areas with ‘Potential Risk’ (risky zones) and areas of ‘Actual Risk’ as well as projects the probability of the worse degradation in future. The Qareh Aghaj subbasin (1,265,000 ha), which covers the upper reaches of Mond River, has been chosen for a test risk assessment of this kind. The preparation of risk maps based on the GIS analysis of these indicators will be helpful for prioritizing the areas to initiate remedial measures. The different kinds of data for indicators of water erosion were gathered from the records and published reports of the governmental offices of Iran. By fixing the thresholds of severity classes of the nine indicators a hazard map for each indicator was first prepared in GIS. The risk classes were defined on the basis of risk scores arrived at by assigning the appropriate attributes to the indicators and the risk map was prepared by overlaying nine hazard maps in the GIS. Areas under potential risk have been found to be widespread (63%) in the basin and when classified into subclasses with different probability levels the model projects a statistical picture of the risk of land degradation.

Risk assessment of water erosion for the Qareh Aghaj subbasin, southern Iran

Soil erosion is the dominating factor of damaging roads in Iran. Roads are a critical component of civilization. Developing and maintaining the economic activity that is vital for the quality of modern life would be difficult without roads. Accelerated erosion and increased sediment yields resulting from changes in land use are critical environmental problems, and one of the important changes is road construction. Construction and condition of roadways are associated with direct and indirect impacts on soil erosion. This paper presents the relationship between soil erosion and some characteristics such as distance to roadway, slope, and parent material in Latian Watershed, Tehran Province, Iran. Soil erosion map was interpreted using aerial photos and GIS technology. Buffer zones, subdivided into 12 strips, each 0.2 km wide, which were located alongside roadway. The distribution patterns of various types of erosion were also identified by GIS by overlaying road buffer strips and soil erosion map. The results show that soil erosion landform such as land slide, badland, bank erosion, channel erosion, etc. found in buffer zones along both sides of roads.

Ahmadi Hasan

Papers

Quantitative assessment of desertification in aghqalla & gomishan plain for creation of a regional model

Application of analytical hierarchy process (ahp) in assessment of de-desertification alternatives case study: khezrabad region, yazd province

Calibration of medalus model to present regional model for desertification intensity (case study: kashan)

Evaluation of desertification intensity in segzi plain using imdpa model

A model for evaluation of watershed management projects