نتایج جستجو برای: soil and vegetation classes
تعداد نتایج: 16884126 فیلتر نتایج به سال:
Abstract This paper presents a quantitative account of vegetation–environmental factor relationships in arid rangelands. Vegetation cover was recorded using Braun-Blanquet combined abundance-cover scale in each quadrat. Within each quadrat, one profile was dug and soil samples being taken at 0-20cm and 20-100cm depths. Under study physical-chemical characteristics included texture, lime, orga...
Using accurate and low-cost methods to monitor quantitative changes in vegetation cover play an important role in the efficient and sustainable management when the area is too large. In this study, the changes of vegetation cover were investigated using satellite data of TM (Landsat_5) and oli (Landsat_8) sensors for a 30-year period (1988-2018) in Chaharbagh rangeland of Golestan province. T...
Rangeland ecosystems in arid and semiarid regions strongly were influenced by climatic factors and their kind of exploitation of management. These changes usually occur in combination and structure of vegetation over time. Because understanding the dynamics of pasture can choose the appropriate management practices and proper help, The changes of vegetation in desert ecosystem of Jajarm area, b...
Accurate estimation of green aboveground biomass in arid and semiarid grassland is essential for a variety of studies, such as sustainable grassland management, fire risk assessment, climate change, and environmental degradation. A great need exists for the establishment of robust method for estimating green aboveground biomass in arid and semiarid grassland due to the influences of soil backgr...
Understory vegetation plays a vital role in regulating soil carbon (C) and nitrogen (N) characteristics due to differences in plant functional traits. Different understory vegetation types have been reported following aerial seeding. While aerial seeding is common in areas with serious soil erosion, few studies have been conducted to investigate changes in soil C and N cycling as affected by un...
آموزش واژه با بهره گیری از یادگیری تلفیقی و نرم افزارهای چند رسانه ای در کلاس های آموزش زبان انگلیسی
the purpose of this study was to investigate the impact of blended learning and multimedia softwares on iranian efl students vocabulary learning. in addition, the present study tried to examine the extent to which multimedia softwares can be applied into efl classes in iran. it also attempted to find out students attitudes toward using these softwares. to this end, 87 iranian efl learners at el...
In this study we evaluate the effects of different types on soil Physical and chemical Properties and plant species biodiversity in the hyrcanian forests of Iran. For this porpuse 33 sample plots were established in 5 vegetation types consist of pure beech (Fagus orientalis), Ash plantation (fraxinus excelsior), spruce plantation (Picea abies), mixed forest and degraded forest. In each ...
The surface displacement by seasonally freezing bulge and thawing subsidence are main hazards for engineering construction in permafrost regions, especially for the Qinghai-Tibet railway. For detecting the distortion at permafrost area, we try to study the interferometric method of monitoring the deformation at permafrost area with time-series EnviSat ASAR data. In this paper, the coherence cha...
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...
BACKGROUND Management regimes for vegetation restoration of degraded grasslands can significantly affect the process of ecological succession. However, few studies have focused on variation in the soil seed bank during vegetation restoration under different management regimes, especially in saline-alkaline grassland habitats. Our aim was to provide insights into the ecological effects of grassl...
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