tayebeh sohrabi; Abbas Ali Vali; Abolfazl Ranjbar Fordoei; sayed Hojat Mousavi
Abstract
Dust event is one of the secondary complications of ecosystem in arid and semi-arid areas. This phenomenon results from system feedback against multiple factors of pressure and destruction. One of the most important foundations of ecosystems is vegetation. Because the vegetation factor reflects many ...
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Dust event is one of the secondary complications of ecosystem in arid and semi-arid areas. This phenomenon results from system feedback against multiple factors of pressure and destruction. One of the most important foundations of ecosystems is vegetation. Because the vegetation factor reflects many factors in the ecosystem, therefore, the interaction of factors can be understood by studying the relationship between its changes and other factors such as dust phenomena. The aim of this study was to investigate the effect of vegetation and relationship with dust events in Esfahan province during 2000-2016 using Geographic information system and Normalized difference vegetation index. The data of dusty days in the region synoptic stations were provided from Meteorological Organization and the frequency of dusty days in different years were determined. Using the method of Normal Kriging in GIS; dusty days were zoned. Vegetation map was prepared based on NDVI in July for each year using MODIS image. The regression analysis of annual dust and vegetation index were also performed to quantitatively analyze the effect of vegetation cover on the occurrence of dust.The results showed. Vegetation cover has been the lowest during the study period in the east and center of the province. The NDVI was also the lowest in 2011-2012 and 2015, with a change from 0.69 to -0.19. The results showed significant correlation between the number of dust event and vegetation distribution
mahshid souri; mina gayeb; Javad Motamedi
Abstract
Rangelands, using a variety of renewable natural resources are as well as economic value, in terms of effects on soil and water conservation that are very important. This study was conducted in Nushan West Azerbaijan province. Determining the susceptible areas of rangeland to degradation done by out ...
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Rangelands, using a variety of renewable natural resources are as well as economic value, in terms of effects on soil and water conservation that are very important. This study was conducted in Nushan West Azerbaijan province. Determining the susceptible areas of rangeland to degradation done by out ranking technique PROMETHEE II was used. In this study, to determine the rangeland susceptible to degradation used numerous effective criteria such as precipitation, slope, erosion, sediment, runoff, discharge, production, pasture conditions, pH, conductivity, organic carbon, soil, land use, population density and the presence of villages in the catchment area of 7439 hectares was used. Weight criteria were determined using the Shannon entropy. Due to the weight and value of criteria for each vegetation type, analyzed data for each of them using PROMETHEE II. Finally, the rangeland degradation areas were divided in 3 category including; high, moderate and low classes by using K-means method.
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.
