نتایج جستجو برای: desertification indices
تعداد نتایج: 84578 فیلتر نتایج به سال:
Desertification is a global problem in most arid and semiarid countries including Iran are facing with this problem. Desertification causes many restrictions in terms of agriculture, food security, livestock rising, industry and providing service costs. This phenomenon is a process which gradually developed and accelerated and adjustment costs is increasing exponentially, so according to resour...
Abstract Desertification is one of the fundamental problems that threaten many arid and semi-arid areas. The formulation of the United Nation Convention to Combat Desertification (UNCCD), adopted in Paris, 1994 and ratified in 1996, with the active participation of Egypt, gave emphasis on combating the major threats to sustainability of dry lands. Recently, different models were developed to fo...
Desertification is a serious threat to the sustainability of the environment and to human habitation. Kerqin sandy land is the largest sandy land in China, and is one of the most important origins of sandstorms in Northern China. Land desertification and frequent sandstorms in the spring strongly affect the growth of grassland vegetation and crops, and the effective of eco-environment in this r...
In this paper, the spatial distribution of stony desertification characteristics and its influencing factors in Karst areas in different sampling scales are studied using a grid sampling method based on geographic information system (GIS) technology and geo-statistics, with the rock bareness rate obtained through sampling with 150m × 150m grids in the Houzhai River Basin being taken as the orig...
the kind of land use and intensity of its change is considered as important desertification indices in different models. land use change is one of the main anthropogenic factors in the desertification. the current research was carried out around imam khomeini airport, with an area of 32000 km2, in order to evaluate mentioned area's land use changes effects during 1955-2003 on desertification. t...
Methodologies based on indicators occupy a prevalent place when assessing ecosystem functioning and monitoring desertification processes because they are affordable yet do not compromise accuracy. The landscape function analysis (LFA), developed in Australia by David Tongway (CSIRO), uses soil surface indicators to assess the condition of a given ecosystem by producing three numerical indices (...
Degradation of semi-arid and arid ecosystems due to desertification is arguably one of the main obstacles for sustainability in those regions. In recent decades, the Mu Us Desert in China has experienced such ecological degradation making quantification of spatial patterns of desertification in this area an important research topic. We analyzed desertification dynamics for seven periods from 19...
pedological criterion affecting desertification in alluvial fans was investigated, for which the map of units was prepared by crossing maps of land use, geology, slope classes and grid layer created by the extension of et geo-wizards in arcgis 10.3. three indices of salinity, erodibility, and permeability of soil were considered and classified. weights of criteria and consistency ratio were cal...
Karst rocky desertification is a special kind of land desertification developed under violent human impacts on the vulnerable ecogeo-environment in karst ecosystem. The process of karst rocky desertification results in simultaneous and complex variations of many interrelated soil, rock and vegetation biophysical parameters, rendering it difficult to develop simple and robust remote sensing mapp...
The Ordos Plateau, a typical semi-arid area in northern China, has experienced severe wind erosion events that have stripped the agriculturally important finer fraction of the topsoil and caused dust events that often impact the air quality in northern China and the surrounding regions. Both climate change and human activities have been considered key factors in the desertification process. Thi...
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