نتایج جستجو برای: particularly in arid and semi

تعداد نتایج: 21759810  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید چمران اهواز - دانشکده مهندسی علوم آب 1393

drought is transient phenomenon , slow , repetitive and integral part of the climate of each region. drought begins with a substantial reduction in precipitation over the long-term average rainfall and over time, reduced soil moisture and surface and ground water resources will continue to decrease. this phenomenon is the most important in bakhtegan basin because of its importance in strategic ...

2012
Clare Duncan Aliénor L. M. Chauvenet Louise M. McRae Nathalie Pettorelli

Droughts can have a severe impact on the dynamics of animal populations, particularly in semi-arid and arid environments where herbivore populations are strongly limited by resource availability. Increased drought intensity under projected climate change scenarios can be expected to reduce the viability of such populations, yet this impact has seldom been quantified. In this study, we aim to fi...

Journal: :desert 0
h.r. keshtkar msc. graduate, university of tehran, karaj, iran h. azarnivand professor, faculty of natural resources, university of tehran, karaj, iran h. arzani professor, faculty of natural resources, university of tehran, karaj, iran s.k. alavipanah professor, faculty of geography, university of tehran, tehran, iran f. mellati instructor, faculty of environment and natural resources, ferdowsi university, mashhad, iran

land cover is one of basic data layers in geographic information system for physical planning and environmentalmonitoring. digital image classification is generally performed to produce land cover maps from remote sensing data,particularly for large areas. in the present study the multispectral image from irs liss-iii image along with ancillary datasuch as vegetation indices, principal componen...

ژورنال: علوم آب و خاک 2020

In semi-arid regions, soils are weakly aggregated and subjected to water erosion processes especially rill and interrill erosion. There is no information on the rate of these water erosion types in semi-arid soils located in the hillslopes. Therefore, this study was conducted to determine the soils susceptibility to these erosion types in semi-arid region. A laboratory experiment was done in ei...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده فنی مهندسی 1385

acknowledge the importance of e-commerce to their countries and to survival of their businesses and in creating and encouraging an atmosphere for the wide adoption and success of e-commerce in the long term. the investment for implementing e-commerce in the public sector is one of the areas which is focused in government‘s action plan for cross-disciplinary it development and e-readiness in go...

2015
Li-Na Xie Hong-Yu Guo Christopher A. Gabler Qing-Fang Li Cheng-Cang Ma

Few studies have investigated the influence of water availability on plant population spatial patterns. We studied changes in the spatial patterns of Caragana stenophylla along a climatic drought gradient within the Inner Mongolian Plateau, China. We examined spatial patterns, seed density, "nurse effects" of shrubs on seedlings, transpiration rates and water use efficiency (WUE) of C. stenophy...

Journal: Desert 2017
H.R. Karimzadeh J. Pourrezaei M. Tarkesh Esfahani M.R. Vahabi S.J. Khajeddin V. Mozaffarian

     Roads have an important role in plants dispersal on different scales. Various plant species settle on roadsides, but some of them can enter the natural environments and threaten their biodiversity. Worldwide knowledge of roadside flora is necessary for local and global management of natural areas. Accordingly, the roadside flora of Northern Khorasan rangelands was studied along the 600 km ...

Severe range degradation was critically extended in many region of Iran and caused many rangelands were restricted and interwoven with croplands in a complex system. Therefore, rangeland planning and inventory as an isolated activity has become almost impossible. Current landscape planning involves contributions of different social organizations often with different interests and with different...

Ali Tavili, Ghasem Assadian Mohammad Jafari Mohsen Mohseni Saravi, Nasrin kolahchi

At the beginning of twenty-first century, the water crisis in the priority policy andmanagement is inside and outside of the country as principle thoroughly human, social,economic and political rulers of the country is considered abundant. The World Bank hasannounced that during 1960 and 2025, water resources in Middle East, from 3430 m3 for theeach person in year reach to 667 m3 because of pop...

Journal: :journal of agricultural science and technology 2009
s. javadi m. s. kiapasha k. mohammadi

reservoir dams are among the main storage systems employed in agriculture for the several past decades. proper operation of these reservoirs is important for irrigation espe-cially in such arid and semi-arid areas like iran, and particularly during dry years. a computational framework for reservoir simulation and flood routing is hereby presented. a key aspect of the reservoir simulation is the...

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