Behzad Rayegani; Gholamreza Zehtabian; Hossein Azarnivand; seyed kazem alavipanah; Sayed Jamaleddin Khajeddin
Abstract
Soil is one of the main non-renewable natural resources in the world and its degradation is considered as a major threat around the globe because it reduces the productivity capacity of soil variability and makes the environment instable in the long turn. Soil degradation has three different ...
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Soil is one of the main non-renewable natural resources in the world and its degradation is considered as a major threat around the globe because it reduces the productivity capacity of soil variability and makes the environment instable in the long turn. Soil degradation has three different aspects: Physical, Chemical and Biological degradation. If any of these aspects of the destruction of the soil can be estimated in an equation, assessment and estimation of the soil degradation can be done easily. To achieve this goal extensive efforts have been made in various parts of the world and different methods for assessing soil degradation have been suggested. In this research latest guideline of soil degradation assessment presented by Land Degradation Assessment in Aridlands is used to desert region of the east of Esfahan and different aspects of soil degradation is assessed by that. According to the findings of this research, LADA methodology of soil degradation easily can be used by most users within the country because the method is simple and provides results as fast as possible. Comparing the results of this method and photos of relative the sampling sites has shown the model is reasonably accurate.
Abazar Esmali; Hasan Ahmadi; Mohammad Tahmoures
Abstract
The aim of this research is to describe the development of a methodology based on present knowledge and available data for evaluation of water erosion behavior and risk as well as modeling and estimation of soil erosion, which is compatible for other similar areas of Iran. Accordingly, the conducted ...
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The aim of this research is to describe the development of a methodology based on present knowledge and available data for evaluation of water erosion behavior and risk as well as modeling and estimation of soil erosion, which is compatible for other similar areas of Iran. Accordingly, the conducted research was based on four major types of water erosions including: sheet, rill, channel and riverbank which have considerable role on sediment yields of Baleghli Chay Watershed, Ardebil Province, were separately and spatially studied. In order to determine the inter-effects of effective factors, the study was conducted using stepwise multivariate statistical tests. For each erosion type, an individual model was then presented. In the next step, after determining of relations between sediment yield and environmental factors (fixed & variable) through statistical analyses and selecting of effective factors on erosion and sediment yields, was created an empirical structure for modeling erosion and sediment yields based on MPSIAC erosion model. In formulation of the new model, were used of eight effective factors on erosion in the area. These factors are susceptibility of geological formation, soil erodibility, rainfall erosivity, runoff erosivity, topography, hydrographic drainage, Normalized Difference of Vegetation Index (NDVI) and field conditions of erosion features. In the presented model, with summation of the scores of mentioned eight factors, obtains the M value, which can estimate the amount of erosion and sediment yields of the area, using exponential formula between sediment yield and M values. In addition, in order to obtain the confidence of presented model, it was used in "Nir" catchment for evaluation the precision. The results showed 11 percent difference. With accepting of this error value, the water erosion hazard map of the area was provided and presented using new model.
Fariba Alavizadeh; Kamalledin Naseri; Ali Golkarian; Ali Tavili
Abstract
Soil erosion is a main hazard in most area of the country specially in arid and semi-arid regions and itis very important because of sedimentation, pollution, increased flooding and its negative effects onsoil productivity. One of the features of arid and semi-arid areas is the presence of low cover ...
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Soil erosion is a main hazard in most area of the country specially in arid and semi-arid regions and itis very important because of sedimentation, pollution, increased flooding and its negative effects onsoil productivity. One of the features of arid and semi-arid areas is the presence of low cover ofvascular plants. These empty spaces are usually good niches for biological soil crusts or cryptogamslike mosses. These crusts contribute to a variety of ecological functions and have different effects onsoil features and vascular plants. The present study was carried out in the rangelands of Torogh dambasin of Khorasan- Razavi province in order to find the effects of such kind of plants (mosses) onwater erosion. For this purpose, artificial runoff streams in plots with two intensity (low and high) for30 minutes. In order to study the effects of different amount of mosses on sedimentation and specificerosion, four different density of mosses in the same experimental situation were studied: high (60-75% of plot), medium (35-50% of plot), low (10-20% of plot) and control (0%). The results ofanalysis of variance and tukey method by the use of Minitab software showed a significant differencein 95% level between the four considered density of mosses and the two intensity of water. As mossesdensity decrease, sedimentation and specific erosion increased consequently. But there were nosignificant differences in infiltration between the different treatments.
M. Akbarian; S. H. Kaboli; N. Moradi
Abstract
Determining the relative sensitivity of land to erosion and its factors, could be the basis of soil conservation programs. The aim of this study is to compare water and wind erosion functions in land degradation of Dasht-e-Jeihoon using PSIAC and IRIFR.EA models and the source studying of aeolian sediments ...
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Determining the relative sensitivity of land to erosion and its factors, could be the basis of soil conservation programs. The aim of this study is to compare water and wind erosion functions in land degradation of Dasht-e-Jeihoon using PSIAC and IRIFR.EA models and the source studying of aeolian sediments in geomorphologic facieses as homogeneous units. The results indicate that in Dasht-e-Jeihoon, water erosion has been transferred fine and coarse grained sediments to the center of plain. In fact, in this region wind erosion fulfills the effect of water erosion in center of the plain. Erosion estimation shows that 50.3 percent of the region includes the mountain facieses )erosional or bare pediment (which water erosion is moderate to high, have minute to low wind erosion and 49.7 percent of the region includes the facieses of Epandage and covered pediment which water erosion is low while wind erosion has moderate to high effects. Water erosion not only results 39.7 percent of the Dashte-Jeihoon sedimentation, but also it has a significant role to supply erodible particles in downstream of the region. Observations and the results showed that for estimating the erosion in dry areas such as Dashte-Jeihoon, we need to use water and wind erosion estimator models as supplements.
