Kourosh Kamali; Gholamreza Zehtabian; TAYYEBEH MESBAHZADEH; Hosein Shahab Arkhazloo; Mahmood Arabkhedri; Alireza Moghaddam Nia
Abstract
The sustainability of soil, especially in fragile ecosystems, is an indispensable indicator of sustainable land management that depends on the physical, chemical and biological properties of the soil. In order to study the soil sustainability in Semnan desert region of farms, gardens and rangelands as ...
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The sustainability of soil, especially in fragile ecosystems, is an indispensable indicator of sustainable land management that depends on the physical, chemical and biological properties of the soil. In order to study the soil sustainability in Semnan desert region of farms, gardens and rangelands as arenas located on an educational farm with different irrigation administrations, the Sustainability Index (SI) and the Cumulative Ranting (CR9 &CR11) were used. Exploring the crust and sampling of surface and subsurface horizons of selected areas and measuring 12 important and effective characteristics of soil physical properties, the indices were calculated in each area and the effects of different types of land use on soil stability were investigated. The results showed that the SI in the surface layer of arable land due to the impact of cultivation and the positive role of organic matter was above one, and in the rest of the land was less than one which indicating the instability of the soil. According to the CR results, surface and subsurface layers of soil were not found in very stable and stable classes in the studied lands. The CR results also showed that the stability soil in the multi cultivates farm is a better condition, it may be due to its positive role in increasing soil correction factors compared to other lands. Correlation analysis of the indices showed that soil organic carbon, structural index, electrical conductivity, sodium adsorption ratio and mean weight diameter have a direct and more effective impact on soil sustainability.
Asghar Zare Chahouki; Ali Salajegheh; Mohammad Mahdavi; Sharam Khalighi; Said Asadi
Abstract
A flow-duration curve (FDC) illustrates the relationship between the frequency and magnitude of streamflow. Applications of FDC are of interest for many hydrological problems related to hydropower generation, river and reservoir sedimentation, water quality assessment, water-use assessment, water allocation ...
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A flow-duration curve (FDC) illustrates the relationship between the frequency and magnitude of streamflow. Applications of FDC are of interest for many hydrological problems related to hydropower generation, river and reservoir sedimentation, water quality assessment, water-use assessment, water allocation and habitat suitability. This study was carried out in 11 selected watersheds with common characteristics such as the 20 years period, the minimum land use change and similar annual water volume through all watersheds in 3 province of: Yazd, Semnan and Markazi which are located in central zone of Iran to regional flow duration curve. It was extracted Q5, Q10, Q20, Q30, Q40, Q50, Q60, Q70, Q80 and Q90 from 11 Hygrometric stations as a dependent variable were derived from flow duration curve. The flow duration curve is regionalized by using morphoclimatic characteristics of the drainage basin. Using multiple regression techniques, the geographic variation of each parameter of the best fitted flow duration model is explained in terms of the drainage area, length of longest flow, Stream slope, mean annual areal precipitation, course from the divide of the basin to the site of interest. The regionalized nonlinear regression equations are successfully used to flow duration curves at other locations within the hydrologically homogeneous regions of center of Iran. A cross-validation Nash–Sutcliffe Efficiency procedure was used to evaluate best fitting of the regional model in ungauged watershed.
