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Several models have been developed to estimate land degradation rate and evaluate desertification severity. This study attempts to apply the MEDALUS (Mediterranean Desertification and Land Use) model by considering existing conditions in the Hamoun wetland, located in south-eastern Iran. At first identification of the main factors affecting the desertification phenomenon was attempted, based on field survey. These factors include climate, soil, vegetation and management practices. Results showed that land management and extreme climate are the most important factors affecting the desertification process. In addition, in some land uses, lack of vegetation accelerates the prevalent wind intensity in the study area (known as “the 120Rozeh” (means 120 days and refers to the wind, with high speeds that blow from the North to the South during summer time) – the most famous Iranian winds) which continues its path without any barrier, and erodes the land surface. Results also indicated that the study area is mostly located in the critical desertification class. Based on the results, it is known that 14% of whole region (12,273 ha) is in the low-critical class, 48.2% (42,251 ha) in the medium-critical class, and 37.8% (33,134 ha) in the high-critical class.

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We measured the impacts of coastal modification on beach erosion and beach retreat conditions, selecting the Miankaleh Region as an example of a complex high-pressure free zone with high levels of engineering and tourism activity. Nine sampling transects, stretching from the shoreline to a 10 meter depth, were defined and 36 sediment samples were collected from the sea bed at depths of 1, 3, 5, and 10 m. After conducting laboratory tests, data were analyzed in terms of sediment dynamic parameters such as grain size, sediment size distribution, mean, median, skewness, kurtosis, standard deviation, and mineral composition. Beach structure and morphodynamic conditions were assessed in the Miankaleh region, by means of satellite image interpretation and field surveys. Results show that from 1978 until the present the average rate of beach retreat rapidly increased due to sea level rise and coastal constructions that have resulted in a progressive increase in sea level height in this region. Erosion vulnerability hazards have also increased in the eastern part of the study area and deposition processes have developed in the western Amirabad region.

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Soil characteristics is very important in water erosion processes. The present investigation was conducted in gully lands of Ardebil Province, Iran, to assess the role of soil texture and structure on aggregate stability using wet sieve method. To achieve the study purposes, mean weighted diameter of aggregates was calculated, and its relationships with lime and clay percentages, sodium absorption ratio and soil organic matter were then determined. The research results showed, in the first and second depth, the organic matter had the highest direct and positive effect on aggregate stability. In first depth, clay and lime had a direct and positive effect on aggregate stability. In both depths, sodium absorption ratio had the highest but negative effect on aggregate stability. Organic matter and clay had the highest direct and positive effect on aggregate stability in the second depth. The highest indirect effect of the parameters on aggregate stability was in second depth due to effect of clay and organic matter on each other. In second depth, lime had the direct and positive effect on aggregate stability. Sodium absorption ratio had a direct and negative effect on aggregate stability in both study depths.

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Different types of soil erosion including gully erosion occur in many parts of Iran. The west of Iran is further threatened by gully erosion due to its specific physical and climatic conditions. However, few studies have been carried out to study the sediment production of gully erosion in Iran. This research was therefore conducted to measure storm-wise sediment production of gully erosion in the west of Iran. To achieve the study objectives, 48 gullies located in three small watersheds viz. Darreh-Shahr, Abbas-Abad and Hollowsh in Ilam and Lorestan Provinces were monitored. The volumes of gullies were measured before and after 5 rainstorms for Darreh-Shahr and Abbas Abad watersheds and 6 rainstorms for Hollowsh watershed from 2005 to 2007. Sediment production was calculated on storm basis for each gully. The results revealed that the minimum and maximum volumes of gully erosion were 0.002 and 1.010 m³, respectively, for one millimeter of rainfall. The results indicated that soil moisture, percentage of silt and clay, amount and intensity of rainfall and drainage area were the most important factors on formation and sediment production of gully erosion.

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The artificial recharge of groundwater (ARG), where practicable, is an easy and economical method for desertification control in the arid and semi-arid zones where overpumping has critically lowered the watertable. Although desiltation of floodwaters, which is a prerequisite for the ARG, leads to rehabilitation of the eroded sites that house the sedimentation basins (SBs), the gradual impermeability of these basins and infiltration ponds by migrating phyllosilicates shortens the economic life of such projects. Therefore, characterization of these minerals is necessary if treatments for their removal are to be found. As soil erosion in the watershed that supplies the ARG systems with floodwater deteriorates the land, and threatens the recharge facilities and other hydraulic structures downstream with siltation, identification of the erosion source facilitates prioritization of soil conservation activities. Clay mineralogical analysis has been developed in recent years as a powerful tool in sediment source attribution. However, applicability of such methods to cases in Iran requires regional studies. Sediment samples were collected at 0-10,10-20, and 20-30 cm increments on two transects in the 1st, 4th and 6th SBs in a Gareh Bygone Plain ARG system. Rock samples were collected on the southern flank of the Bisheh Zard Basin that supplies floodwater to the ARG systems. All samples were characterized by the XRD method. Transmission--electron micrograph (TEM) of one sample was also obtained. Chlorite, mica, smectite, and possibly kaolinite were detected in all samples. The presence of palygorskite was revealed only in a TEM. The non - clay minerals were calcite, dolomite, alkali and plagioclase feldspars, gypsum, halite and quartz. The common origin of these inherited clay minerals precludes their utility in sediment source detection.

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A field study was undertaken with four farming systems (FS) such as; grasses and fodders, agro-forestry, agriculture (new farming systems) and shifting cultivation (old practice), to investigate the effect of land use on the soil properties, erosion and crop productivity on a loamy acidic Alfisol. Besides crops, the livestock were also kept and their dropping were incorporated in the respective watersheds. Soil sampling was done during first week of May every year from 0-20 cm depth, with auger. A significant increase in soil organic carbon (SOC) up to 0.99%, available P up to 17.2 mg kg^-1, K up to 170 mg kg^-1 of soil, pH up to 6.3, was found after 10 years of study over their initial values of 0.46%, 2.7 kg^-1, 105 kg^-1 of soil and 4.9, respectively, in the new FS. In shifting cultivation, K status increased up to three years of study and then subsequently decreased. Diethylen etriamine penta acetic acid (DTPA) extractable Zn, Mn, Fe and Cu decreased in all the farming systems. Exchangeable Al content decreased from 117 to 37 mg kg^-1 of soil, in new FS. The study showed that about 91.1% to 99.1% rainwater could be retained depending on the vegetation cover in new FS, as against 66.3% in the shifting cultivation. New FS ameliorated the soil by decreasing exchangeable Al and Fe and enhancing soil pH. Soil and nutrient losses were significantly less and crop productivity higher in new FS compared to shifting cultivation.

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Water erosion causes a series of on-site as well as off-site damages and problems on natural ecosystem. These damages include soil and nutrient loss and finally loss of productivity which causes costs to the society. So, this study attempts to quantify the economic value of soil productivity conservation as one of the important functions of rangelands vegetation and its economic cost by productivity losses. The soil loss amounts were obtained from integrated Geographic Information System (GIS) and map of erosion vulnerable areas using RUSLE model. Supplementary data such as soil nutrients (NPK) valuated from the measurement plots of a portable rainfall simulator (E65). Field plots were constructed to measure soil nutrients and soil loss from different soil types with different resistance to erosion. Rainfall simulation was carried out in three sites on the basis of geology map and different resistance to erosion. Nine experimental unit plots (1*1 m) were used to correlate nutrient loss to sediment losses. Assuming that nutrient loss by erosion could be replaced by fertilizers, economic cost of major nutrients estimated by market prices of fertilizers. Results showed that mean annual soil loss using RUSLE was 27.44 t ha^-1 y^-1 ranging from 0.0 to 996.06 t ha^-1 y^-1. Also, 114.17 kg ha^-1 y^-1 of N, P, K elements were lost in 2010 due to soil erosion in the degraded rangelands which costs (738944 Rial) 71.5 US$ ha^-1y^-1. Total economic cost of soil nutrient loss in 94978.6 ha of the rangelands of Nour-rud watershed basin, was estimated 70×10^{^}9 Rial (6.8×10⁶ US$). The maximum annual cost of soil nutrient loss was estimated in the "TRujs" geological formation (1.23×10⁶ US$) consisting of "gray shale, silt, sandstone, conglomerate" and the least cost belonged to the "Jl1" geological formation (0.916*10⁶ US$) which consists of "thin gray dolomite limestone". In economic terms there was a direct relationship between soil nutrient loss and its economic cost.

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There are many reports of serious problems of dust storm events in the western parts of Iran. Based on many researches, Iraq is one of the main sources of dust storms in western parts of Iran. The Radial Basis Function Network (RBFN) model has been used to assess wind erosion hazard in Iraq as a main source area of dust storms over several western cities of Iran. The percentage of vegetation is the only changeable factor of RBFN model. The wind erosion hazard map in two time periods (2003 and 2012) verified the vegetation changes over time. The results showed that the vegetation percentage index in all land use types of 2003 was higher than those of 2013. In addition to drought as a natural parameter, overgrazing, dam construction on Tigris and Euphrates Rivers (in Turkey) and high amount of water for crop production are human and policy factors causing loss of vegetation cover in source area and wind erosion exacerbation.

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Background: The large part of sandy soils in Hungary has unfavorable water management properties. Studies have shown that the sewage sludge compost, due to its high organic content, is suitable for improving structure and water management of these soils. The aim of our study was to determine the effects of the application of sewage sludge compost on physical properties of sandy soil.
Materials and Methods: The experiment was established in 2003 at the Research Institute of Nyíregyháza of the University of Debrecen in Hungary to study the utilization of sewage sludge compost in agriculture. In this study, however, the changes of water retention and erodibility of soil were measured for three periods. The soil type of the experiment is Arenosol (Dystric Lamellic Arenosol). The applied compost contained sewage sludge of 40%, straw of 25%, bentonite of 5% and rhyolite of 30%. The compost is applied every 3^rd year in the following amounts: 0, 9, 18 and 27 Mg ha^-1 of dry matter.
Results: The compost treatment had a beneficial effect on soil structure thereby reducing the runoff and sediment loss under high intensity rainfall (130 mm h^-1). However, in the control plot there was significantly higher water erosion. The water retention of soil was slightly increased after compost application.                             
Conclusions: The compost application improved the water management properties of sandy soil, which is connected with organic matter addition into soil. The compost treatment had a beneficial effect on soil structure thereby reducing the runoff and sediment loss.

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An ever increasing population needs more energy and food to be provided from limited resources. Many different problems such as floods and droughts frequently occur and even happen at extreme values throughout the world, since the inherent capability of the resources is not evaluated properly. Soil erosion, as one of the major types of land degra-dation, is supposed to cause serious problems for future and even present generations. However, evaluation of the magnitude and spatial distribution of fundamental types of soil erosion i.e. sheet, rill and gully erosion is an important task to be conducted in devel-oping countries where the necessary bases for development are required. An attempt has been made in the present paper to introduce a technique through which the condition of soil erosion is defined and mapped in the study area. All available and acceptably accu-rate information, such as the geologic sensitivity of the area to erosion, the land type and slope maps, are required for determination of homogeneous work units using overlying. The present character of soil erosion in the field is then evaluated by filling out the revised questionnaire forms adjusted on the basis of criteria mentioned by United States Bureau of Land Management (USBLM) and the final classification of each type of erosion is made according to the sum of scores obtained by each work unit. Finally, the overall situation is generalized in the fractional form. The presented technique has been implemented for more than 6 million hectares of the area of Iran and was able to reflect the governing conditions well and the results should be applied in the management of natural resources to achieve sustainable utilization. For the present study and for demonstrating the details of methodology, a small watershed located in the Markazi large watershed of Iran, known as Barahmoom, and comprising 4236.2 ha was selected as a case study. The presented soil erosion mapping technique can be applied for areas where only basic or very little data and information is available.

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River bank erosion can result in considerable riparian land loss and the delivery of large volumes of sediment to reaches downstream. Consequently, the ability to predict the stability and failure geometry of eroding river banks is an important prerequisite for es-timating the rate of bank erosion and sediment yield associated with bank erosion. In this paper a new model capable of analyzing the stability of layered river banks is introduced. The new model takes into consideration the effects of positive pore water pressure in the saturated portion, and negative pore water pressure in the unsaturated portion, of the bank. Also, the role of hydrostatic confining pressure due to the water level in the river and the effects of the water in tension crack on stability analysis is accounted for. Unlike many previous analyses, the failure plane is not constrained to pass through the toe of the bank. However, it considers only planar-type failure mechanism. Finally the bank profile geometry is not restricted to a special case. The new model has been tested using field data sets from a site on the Sieve River in Italy and a site on Goodwin Creek in Mississippi. The results show some agreement between the predicted and observed values of bank sta-bility.

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Recent studies demonstrate that aluminide coatings are beneficial to wear and erosion resistance and also that oxygen-active elements such as yttrium can remarkably improve this resistance. In this research, the micro-hardness of the aluminide coatings with and without yttrium on 1045 steel was investigated using a micro-mechanical probe. Wear of the samples was measured using a pin-on-disk tribometer. The erosion loss of specimens against soft and hard wheat was also evaluated using a slurry erosion test machine. The data was analyzed statistically using a 3-factor completely randomized design to study the effect of wheat varieties (soft and hard wheat), moisture content at three levels (10±0.5, 15±1.5, and 20±2 % (wet basis)), and rotary velocity of the slurry erosion machine at three levels (200, 400, and 600 rpm) on erosion resistance. The results showed that the aluminide coatings improved the wear and erosion resistance of substrate steel 1045; yt-trium markedly improved the hardness of the aluminide coating and its wear and erosion resistance. The erosion loss of materials was significantly (p<0.01) influenced by the type of wheat, moisture content and rotary velocity. Both aluminide coatings showed higher wear and erosion resistance than 1045 steel substrate.

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  Aims This study has been done to investigate the effects of access road network of Arasbaran forest areas on erosion in order to achieve appropriate criteria for sustainable development in forest areas while protecting forest soil.
Materials & Methods This research was carried out to introduce the SEDMODEL and its capabilities in estimating the production of sediment from road construction Sutanchay watershed in Arasbaran forest, located in the northwest of Iran. From road networks, 10km selected for research. Initially, the maps of geology, slope, rainfall, and drainage density, were prepared in the GIS system. Then, excavation trenches, road surface coverage, and traffic volume were examined in 34 stations through field surveys. The statistical method of Fisher distribution was used to compare the model estimation and observation values.
Findings Statistical analysis of the data showed that there was no significant difference between sediment delivery and Metric method in the erosion assessment resulting from access roads. Standard Error of the metric method and the SEDMODEL was calculated to be 1.34×10^-3 and 1.37×10^-3, respectively. The results showed that sedimentation caused by road surface was more than 19,000tons, of which 240ton are related to 3km of asphalt road and the rest are related to 7km of dirt road. Total sedimentation of the watershed was estimated to be 46,000ton.
 Conclusion The application of sediment delivery model provides a realistic estimate of forest soil erosion caused by the road network. This model can be considered as a planning criterion in the sustainable development of forest areas.

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Hairsine and Rose (1991) developed a process-based soil erosion model which described the erosion transport of multiparticle sizes in sediment for rain-impacted flow in the absence of entrainment in overland flow. In order to test this model laboratory experiments were carried out in a detachment tray using simulated rainfall. Three contrasting soil types were subjected to simulated rainfall at different rates (25-110 mm h-1) in a 3530 10 cm detachment tray. Rainfall was applied using a rainfall simulator with a single scanning nozzle located four meters above the soil surface that emitted drops with a mean diameter (volumetric D50) of 1.5 mm. Results showed that the Hairsine and Rose model can clearly describe the sensitivity of different soils to erosion by introducing three terms of detachability, re-detachability and settling velocity, though the model is unable to describe aggregate breakdown which takes place in one of the soil at higher rainfall rates. The experimentally observed relationship between ponding water depth and soil detachability parameters did not agree with previously proposed theories. In addition, the results showed that the Hairsine and Rose model tends to over-predict values at the lower end of the scale, and under-predict values at the upper end, although the average sediment concentration predicted for the entire data set is not greatly different from the average measured values.

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Abstract Soil erosion is one of the most important factors causing decline of soil fertility, siltation of different kinds of waterways, reduction of reservoir capacity, increase in destructive risk of flooding and other environmental degradations. In order to mitigate the negative effects of soil erosion and sediment production in watersheds, determining amount and source of sediment is imperative. Since most of Iran’s watersheds are ungauged, use of erosion and sediment estimation models are needed. But for selection of applicable model the models first have to be tested and/or evaluated. In order to achieve to this goal, a research study was carried out to evaluate MPSIAC model in GIS environment based on the observed data of sediment of the Nojian sub-watershed located in southeast of Khorram Abad city in the Lorestan province-Iran. In so doing, to run the selected model after introducing the information layers into the GIS program and combining the layers in MPSIAC model, the given catchments were divided into 527 homogenous units. Then, erosion rate and sediment yield were estimated in these homogenous units. The amount of estimated sediment yield by using MPSIAC model was 489372.2 T/y. For comparison of the model results, the amount of measured sediment in hydrometric station was considered as the control level, which was 812410 T/y. The outcome of the research showed that estimating sediment by using MPSIAC model in comparison to measured sediment was 0.602. The results of the assessment on observed differences show that calibration of the empirical models is needed first to resolve the limitation of the models in correspondence to the existing condition of the watersheds. It can be concluded that in order to accept or reject the result of the sediment yield estimation using the MPSIAC model with high confidence, the model first should be calibrated based on the existing condition of the Iran’s watershed.

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Stream erosion is one of important cause for the increase amount of sediment .Countless factors plays important role as a single or in set,when acts as erosion's factors on stream beds or on slopes and delivers materials in streamflow.Aggradation and degradation landforms and changing shape of longitudinal profiles of rivers at time,are evidences of these operation.The shape of longitudinal profiles gives important information about processes .By use of the regression analyses ,explained and interpreting of shape of longitudinal profiles and to compare many rivers with each other is possible.Evolution valleys defines rate of erosion at bed of rivers or basin.In this articles ,analyses erosion at longitudinal profiles of rivers concern to valleys and basin and area zonation with many type of erosion in study area .The results of this study show that,Garangoo basin settles in mature stage and medium erosionis prevail.

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An experiment involving erosion simulation was conducted at the Soil and Water Con-servation Research Center of the University of Tehran. A split-factorial plot with four replications was designed. Five soil desurfacing treatments of blank, 5, 10, 15, and 20 cm of soil surface removal (E0, E5, E10, E15, and E20) were carried out, respectively. Fertilizer treatments were 0, 65, and 130 kg ha-1 of urea (equal to 0, 30, and 60 kg ha-1 of pure N) and 0, 107, and 214 kg ha-1 of triple super phosphate (equal to 0, 50, and 100 kg ha-1 of P2O5). Wheat (Triticum aestivum), Sardary cultivar, was cultivated in November 2001. To-tal precipitation was 223 mm during the growing season and 336 mm for the whole year (23 September 2001–22 September 2002). In order to reduce the effect of drought stress, three supplementary irrigations were applied during the growing season (13mm each). The crop was harvested in July and plant density recorded. Grain, dry matter and straw yields, as well as 1,000 grain weight were determined. The results showed that erosion had a significant effect (P<0.05) only on dry matter and straw yields. Each centimeter of soil surface removal, induced a reduction of 0.8% in dry matter. Phosphorus fertilizer had a significant effect (P<0.01) on yield parameters, relatively compensating the negative ef-fects of erosion. Nitrogen fertilizer did not show any significant effect on the determined parameters.