نتایج جستجو برای: land desertification

تعداد نتایج: 119172  

Journal: :desert 0
h. ahmadi professor, science and research branch, islamic azad university,tehran, iran h. azarnivand professor, faculty of natural resources, university of tehran, karaj, iran m.r. ekhtesasei associate prof., faculty of natural resources, yazd university, yazd, iran m. tazeh assist. prof., faculty of natural resources, ardakan university, ardakan, iran

there have been different indices identified for desertification. among these is technogenic desertification index which seems much more efficient. in this study, some of technogenic desertification indices were studied and evaluated. first land use maps of the region were taken from irs-pan satellite image and aerial photos analysis. after evaluating the area of different uses, lands that had ...

Land degradation in arid and semi-arid regions caused by climate change and human activities makes it more susceptible to desertification. The aim of this research is assessing the intensity of desertification in Roudab plain of Sabzevar city using IMDPA model. So two criteria of climate and water as the main criteria affecting desertification process were considered based on field observations...

2006
J. XIAO Y. SHEN

The grain size composition of topsoil characterizes the soil texture and other physical properties. The coarsening of topsoil grain size is a visible symbol of land degradation; thereby the change in topsoil grain size can be potentially used to monitor desertification using remote sensing. This study proposes a new index for detecting topsoil grain size composition through ground in situ soil ...

2004
Juan J. Oñate Begoña Peco

Two related land use change dynamics characterise the Guadalent!ın basin (southeast Spain) as one of the most severe cases of desertification in Europe: (1) expansion of highly productive irrigated agriculture in the valley, and (2) intense contemporary changes in the surrounding impoverished dry lands. On the basis of documented information, we trace the effects of past policies on these dynam...

2004

This paper provides an overview of linkages between the phenomena of land degradation and desertification and food insecurity. It reviews the basic concepts linked to food security and records main coping strategies, policy challenges and fields or action. It describes the approach taken by the United Nations Convention to Combat Desertification (one of the three multilateral environmental agre...

G.A. Heshmati

There are more than 750 counties in 13 provinces and autonomous regionsconstituting 30% of China lands which are facing serious problem of desertification. Theseareas are mainly distributed in arid, semi-arid and dry sub-humid areas in the western part ofNortheast China, North central china and most of northwest china. Biological methods are theultimate way for drift sand stabilization and a fu...

Journal: :journal of rangeland science 2011
g.a. heshmati

there are more than 750 counties in 13 provinces and autonomous regionsconstituting 30% of china lands which are facing serious problem of desertification. theseareas are mainly distributed in arid, semi-arid and dry sub-humid areas in the western part ofnortheast china, north central china and most of northwest china. biological methods are theultimate way for drift sand stabilization and a fu...

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...

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