نتایج جستجو برای: vegetation degradation
تعداد نتایج: 196873 فیلتر نتایج به سال:
Negative impacts of gully erosion in marly areas are severe due to improper landuse practices such as irrigation, tillage, overgrazing and degradation of vegetation cover. The objective of this research was to evaluate gully thresholds related to plant vegetation cover and landuse change in the Agriculture (AG), Fair Rangeland (FR) and Weak Rangeland (WR) areas of Ghaasr-e-Shirin, Kermanshah, I...
Improper use of natural resources, especially soil, causes its degradation and severe soil erosion. Water erosion is an important factor causing soil degradation. Land use change of pasture would result in severe soil erosion mainly due to the reduction of vegetation cover and also surface soil disturbance. The objectives of this study were to estimate the amount of sediment, runoff and nutrien...
In this study, we extend a model of daily dryland dynamics by parameterizing a modified version of a minimalistic annual model to examine how the statistical structure of annual rainfall and grazing intensity interact to influence dryland vegetation. With a Monte Carlo approach, an ensemble outcome provides a statistical description of likely dryland vegetation dynamics responding to variations...
The rangeland in the Khangai mountain region in Mongolia has degraded for the last decades mainly because of overgrazing and climate change. Livestock production is important part of the economy and is based on natural rangeland. In this research we seek to elucidate the influence of five years (2004-2009) of protection from grazing on vegetation cover of different degradation levels of Fes...
Current literature suggests that grassland degradation occurs in areas with poor soil conditions or noticeable environmental changes and is often a result of overgrazing or human disturbances. However, these views are questioned in our analyses. Based on the analysis of satellite vegetation maps from 1984, 1998, and 2004 for the Xilin River Basin, Inner Mongolia, China, and binary logistic regr...
بررسی ارزش غذایی تاغ و عمل آوری آن با سود و آهک در مراحل مختلف رشدبا استفاده از روش کیسه های نایلونی
abstract this study is carried out to determine the chemical composition in the three vegetative stages of the haloxylon sp., degradation parameters, with adding naoh and ca(oh2 ). for this purpose, in may and october and january 2010 enough some haloxylon sp. of the ammary area was prepared. crude protein and ash percentage are decrease, neutral detergent fiber percentage with pragress stage ...
negative impacts of gully erosion in marly areas are severe due to improper landuse practices such as irrigation, tillage, overgrazing and degradation of vegetation cover. the objective of this research was to evaluate gully thresholds related to plant vegetation cover and landuse change in the agriculture (ag), fair rangeland (fr) and weak rangeland (wr) areas of ghaasr-e-shirin, kermanshah, i...
When choosing which environmental attributes to monitor in assessing disturbance, it is important to consider not onlywhichmetric will provide themost sensitive indicator of disturbance, but also the spatial considerations of where in the landscape thatmetric will bemost responsive to change.Degradation in landscapes is often unevenly expressed because: (i) disturbance is spatially localised, (...
Under the prevailing variable natural conditions nomadic pastoralism was the most suitable form of land use in Mongolia and the neighboring countries in the past. Furthermore, small areas were used for agriculture in some regions. Therefore, anthropogenic influence was present throughout history. In the forest steppe zone this led to the disappearance of forest sites which then gave way to mead...
Land condition assessment is a basic prerequisite for finding the degradation of a territory, which might lead to desertification under climatic and human pressures. The temporal change in vegetation productivity is a key indicator of land degradation. In this paper, taking the Otindag Sandy Land as a case, the mean normalized difference vegetation index (NDVI_a), net primary production (NPP) a...
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