نتایج جستجو برای: desertification intensity

تعداد نتایج: 182836  

2015
Yongfang Wang Jiquan Zhang Enliang Guo Zhongyi Sun

Desertification is a typical disaster risk event in which human settlements and living environments are destroyed. Desertification Disaster Risk Assessment can control and prevent the occurrence and development of desertification disasters and reduce their adverse influence on human society. This study presents the methodology and procedure for risk assessment and zoning of desertification disa...

Journal: Desert 2011
Gh.R. Zehtabian H. Azarnivand H. Khosravi N. Shakerian

Desertification refers to land degradation phenomenon in arid, semi-arid and dry sub-humid areas, resulting from various factors including climate variation and human activities. For evaluation and mapping of desertification many research have been conducted leading to regional and local models. In this research, among different existing methods IMDPA‌ was selected and desertification intensity...

Ahmad Pahlavanravi Mahdiye Ebrahimi Nasrollah Aslinezhad, Nasrollah Basirani Rasoul Kharazmi

Objective: More than 75 percent of Iran is located in arid and semi-arid then land degradation and desertification are one of the crises ecological. We require a proper understanding of causes and processes of desertification to control the huge phenomenon on the global and regional situation. Because southeast of Iran located in arid land then assessment of desertification is very importance f...

Ahmad Pahlavanravi Mahdiye Ebrahimi Nasrollah Aslinezhad, Nasrollah Basirani Rasoul Kharazmi

Objective: More than 75 percent of Iran is located in arid and semi-arid then land degradation and desertification are one of the crises ecological. We require a proper understanding of causes and processes of desertification to control the huge phenomenon on the global and regional situation. Because southeast of Iran located in arid land then assessment of desertification is very importance f...

2015
David A Seekell Vasilis Dakos

Regime shifts are abrupt transitions between alternate ecosystem states including desertification in arid regions due to drought or overgrazing. Regime shifts may be preceded by statistical anomalies such as increased autocorrelation, indicating declining resilience and warning of an impending shift. Tests for conditional heteroskedasticity, a type of clustered variance, have proven powerful le...

2011
R. C. Balling

Drylands throughout the world have always undergone periods of degradation due to naturally-occurring fluctuations in climate. However, over the past century, the human population in drylands has grown exponentially and the resulting pressures on the landscape have exacerbated various desertification processes, particularly in Africa. The degradation of drylands has led to changes in local, reg...

Journal: :desert 2011
m jafari m.a. zare chahouki h. ahmadi h.r. abbasi

one of the characters in iranian model of desertification potential assessment (imdpa) is soil. since soil is very important in the degradation of land, so some indices were determined for this character in order to evaluate desertification potential of arid, semi-arid and dry sub humid areas of iran. the indices included soil texture, deep gravel percentage, soil depth, and ec. to calibrate th...

Journal: :desert 0
m jafari professor, faculty of natural resources, university of tehran, karaj, iran m.a. zare chahouki associate professor, faculty of natural resources, university of tehran, karaj, iran h. ahmadi professor, islamic azad university, science and research branch , tehran, iran h.r. abbasi research instructor, forest, range & watershed management organization, tehran, iran

one of the characters in iranian model of desertification potential assessment (imdpa) is soil. since soil is very important in the degradation of land, so some indices were determined for this character in order to evaluate desertification potential of arid, semi-arid and dry sub humid areas of iran. the indices included soil texture, deep gravel percentage, soil depth, and ec. to calibrate th...

ژورنال: علوم آب و خاک 2013
حمیدرضا کریم‌زاده, , رضا جعفری, , علی خنامانی, ,

Soil characteristics are the most powerful factors in desertification phenomenon. The purpose of this study was investigating soil characteristics as indices for evaluating desertification intensity. The most important indicators of the soil that affect desertification were selected in the present study. Soil samples were taken from Segzi desert vicinity located in the east of Isfahan city with...

2013
Lihua Zhou Yanling Zhu Guojing Yang Yiqi Luo

In northern China, the recent eco-environment protective policies played a very important role in the ecological environment protection and rehabilitation. To better understand the quantitative effect of the prohibiting grazing policy on grassland desertification reversal process, in this paper, Yanchi County was selected as a case study to conduct a quantitative research on the effect of prohi...

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