Mohammad Tahmoures; davud nikkami
Abstract
Erosion and sedimentation phenomena are two inevitable phenomena of watersheds that are subject to complex factors. Identifying these factors and recognizing their effect on erosion and sediment will help in better planning to reduce the damage caused by erosion and sediment in a basin. In this study, ...
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Erosion and sedimentation phenomena are two inevitable phenomena of watersheds that are subject to complex factors. Identifying these factors and recognizing their effect on erosion and sediment will help in better planning to reduce the damage caused by erosion and sediment in a basin. In this study, to determine the factors affecting sedimentation, the Urmia Lake watershed was selected as the study basin. After identifying 30 characteristics affecting the sedimentation of sub-basins of the study area, including hydrological, physiographic, geomorphological, geological and soil characteristics, climate, land use and vegetation as independent variables, the amount of sediment produced in each sub-basin. Was identified as a dependent variable. Using factor analysis, principal component analysis (PCA), cluster analysis and stepwise multivariate regression between selected independent variables and dependent variable using SPSS software Statistical relationship was obtained between sedimentation of sub-basins and watershed characteristics. According to the selected regression model, it is determined that the amount of sediment in the watershed of Lake Urmia to five factors of agricultural land area (rainfed, irrigated and orchards), the area of sub-basins, the total area of erosion and Quaternary structures, average discharge The annual and basin form factor depends on the fact that these five factors control 89% of the sediment production changes in the selected sub-basins, which is significant at the 5% confidence level. In general, the factors affecting erosion and sedimentation of the Urmia Lake watershed can be divided into three groups: human factors and land use change, geology and physiography.
Shiva Eyvazi; Sasan Babaei Kafaki; Mohammad Jafari; Mohammad Tahmoures
Abstract
Water, soil, pasture, forest, etc. are a valuable divine deposit for the people of any society and the national wealth of that society, which not only should be tried to preserve and protect these national assets, but should By adopting principled, technical, and regenerative exploitation policies, it ...
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Water, soil, pasture, forest, etc. are a valuable divine deposit for the people of any society and the national wealth of that society, which not only should be tried to preserve and protect these national assets, but should By adopting principled, technical, and regenerative exploitation policies, it passed on these most precious sources of life to future generations. With the increasing power of technologies in the exploitation of natural resources, the environmental-environmental balance in recent centuries has been disturbed to the detriment of nature, which has created miserable and sometimes irreparable conditions and is referred to as the crisis of natural resources and the environment. It becomes. Today, the international community sees the solution to this dilemma as protecting the environment, and in doing so, wants to know how it can draw on religious teachings in this important matter. The mentioned research seeks to answer this question by descriptive-analytical method. The results show that in order to get rid of the current environmental crisis, we must refer to moral principles and religious texts, especially Islam, because the basis of the crisis in renewable natural resources is the moral crisis among humans and attention to the fundamental values of Islam. Due to its divine and moral support, it plays a key role in the sustainability and protection of the environment and renewable natural resources.
Mohsen Asadollahi; Mohammad Jafari; vahid sayare; Ali esmaeili; Mohammad Tahmoures
Abstract
Wind erosion is one of the most important aspects of land degradation in arid and semi-arid regions, which 20% of land area of the world has been influenced by wind erosion. The wind increases the desertification process by displacing sand dunes. Therefore, the stabilizition and preventing the moving ...
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Wind erosion is one of the most important aspects of land degradation in arid and semi-arid regions, which 20% of land area of the world has been influenced by wind erosion. The wind increases the desertification process by displacing sand dunes. Therefore, the stabilizition and preventing the moving sands is essential. A strategy to combat this phenomenon is to reduce wind speed or to increase surface cover and soil resistance against erosion winds. The application of mulch or soil cover is one of the methods widely used to stabilize moving sands. For this purpose, a study was done at the Research Station International Desert Research Centre in Kashan city. The main purpose of this study was to investigate the effect of Multivariate biopolymer treatment at three concentrations (15%, 30% and 60%) on the moisture content of three sand depths (first depth of 0-5 cm, second depth of 5-10 cm and depth of third 10-20 cm), and study this mulch Compared with levels without mulch on the sand. Results showed soil moisture retention in Mulching compared to the control treatment, and statistically, there was significant differences between different depths of soil moisture Mulching compared to the control treatment and in between the first, second and third depths, the first depth had the highest increase in moisture holding compared to the Control treatment.
Mohammad Jafari; Mohammad Tahmoures; Mohsen Naghiloo
Abstract
The purpose of this research is investigation of relationship between vegetation cover and soil characteristics and determination of the most important soil factor that effects on quantity variations and kinds of vegetation cover in the study area. The study area is located in west of Tehran province ...
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The purpose of this research is investigation of relationship between vegetation cover and soil characteristics and determination of the most important soil factor that effects on quantity variations and kinds of vegetation cover in the study area. The study area is located in west of Tehran province and south eastern of Hashtgerd, next to Najm-abad village. After field study, the index vegetation types were selected and randomized-systematic sampling method has been used for soil and vegetation cover sampling in each of key area. The area of each plot was determined according to kind of plant species and species distribution using minimum area method. Some vegetation cover parameters such as canopy cover percentage, density and frequency of plant species were measured in the area. Then soil sampling were done from 2 horizon 0-10 cm and 10-30 cm in each plot and soil attributes such as texture, pH, organic carbon percentage and gypsum were measured in soil laboratory. Afterwards statistical methods like multivariate regression, analysis of variance and statistical techniques were used for analyzing of soil and vegetation cover data. Results showed that there is not any specific difference between soil and vegetation data except for gypsum. In other words the effective factor on vegetation cover variation was soil gypsum.
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.
mohsen Naghiloo; mohamad Jafari; mohamad Tahmoures; asghar Kohandel; farinaz Hamedanian
Volume 63, Issue 1 , June 2010, , Pages 119-11
Abstract
The purpose of this research was to investigate the relationship between vegetation cover and soil characteristics in order to determine the most important soil factors which affect on quantitative variations and types of vegetation cover in the study area. The study area is located in west of Tehran ...
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The purpose of this research was to investigate the relationship between vegetation cover and soil characteristics in order to determine the most important soil factors which affect on quantitative variations and types of vegetation cover in the study area. The study area is located in west of Tehran province and southeast of Hashtgerd, next to Najm-abad village. After field studies, the index vegetation types were selected and randomized-systematic sampling method was used for soil and vegetation cover sampling in each key area. The area of each plot was determined according to type of plant species and their distribution using minimum area method. Some vegetation cover parameters such as canopy cover percentage, density and frequency of plant species were measured in the area. Then soil sampling were done from 2 horizons including 0-10 cm and 10-30 cm in each plot and soil attributes such as texture, pH, organic carbon percentage and gypsum were measured in the laboratory. Afterwards, statistical methods like multivariate regression, analysis of variance and RDA technique were used for analyzing soil and vegetation cover data. The results showed no specific difference between soil and vegetation data except for gypsum. In other word the effective factor on vegetation cover variation was soil gypsum.
M Jafari; M Tahmoures; M. Naghiloo
Volume 62, Issue 1 , June 2009
Abstract
The use of GIS tools is one of the newest methods for performance of different land evaluation and planning projects. This research with the purpose of determination of appropriate landuse to natural land potential and improvement of land management of catchments was executed using GIS-tools in Taleghan ...
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The use of GIS tools is one of the newest methods for performance of different land evaluation and planning projects. This research with the purpose of determination of appropriate landuse to natural land potential and improvement of land management of catchments was executed using GIS-tools in Taleghan area. At first ecological and socio-economic resources determined, mapped and entered to GIS environment. Then by analysis of more than 15 information layers, homogeneous and ecological units determined. By the use of watershed management and combined land planning model and in accordance with natural and socio-economic characteristics of the watershed, suitable landuses were proposed. At last optimum landuse map and the existing state of landuse map were adapted in GIS space. The results showed that 17 percent of the watershed area has suitable landuses while 83 percent of the watershed area needs landuse change.
