نتایج جستجو برای: arid region
تعداد نتایج: 552339 فیلتر نتایج به سال:
one of the characteristics in iranian model of desertification potential assessment (imdpa) is vegetation. sincevegetation is very important factor in the degradation of land, so some indices were determined for this item in order toevaluate desertification potential of arid, semi arid and arid sub humid areas of iran. the indices included vegetationcondition, exploit and revegetation. to calib...
Understanding nitrous oxide (N2O) fluxes from agricultural soils in semi-arid regions is required to better understand global terrestrial N2O losses. Nitrous oxide fluxes were measured from three rain-fed, cropped soils in a semi-arid region of south-western Australia on a sub-daily basis from 1995 to 2014 using automated chambers. Western Australia’s grain-belt includes 7 million hectares of a...
Potato has become one of the primary cash crops in the arid region of the Loess Plateau. However, what and how cereal crops to rotate with potato is better for the farmer’s income and environment is unclear now. 11 potato based rotation systems were simulated in Yulin, using EPIC model based on local information. Results showed 1) Though mean potato yield decreased from 6.84 to 5.38 t/hm, the m...
Precipitation is the main water source for vegetation survival in arid and semi-arid areas. However, previous studies always focus on the effects of precipitation in different time scales, but ignore the effects of precipitation in different spatial scales. To further study the effects of precipitation fluctuation in different spatial scales, we used the wavelet analysis method to analyze its t...
a new species of springtail (symphypleona, collophoridae), Collophora brasilis sp. nov., is described, the first species known from brazil. the species is distributed from the coastal region to the semi-arid region in northeastern brazil. it is characterized by the reduction in the trochanteral setae and teeth on the empodial complex. diagnostic features are illustrated and compared to other me...
Vegetation productivity is an essential variable in ecosystem functioning. Vegetation dynamics of dryland ecosystems are most strongly determined by water availability and consequently by rainfall and there is a need to better understand how water limited ecosystems respond to altered rainfall amounts and variability. This response is partly determined by the vegetation functional response to r...
flood frequency analysis is faced with the problem of data and information limitation in arid and semi-arid regions. particularly in these regions, the length of records is usually too short to ensure reliable quantile estimates. more than 75% of iran is located in arid and semi-arid regions and despite the low annual precipitation, often large floods occur. one way to provide more information ...
AIM This study was conducted on Ouled Djellal ewes in arid area of south-east Algeria in order to reveal the influence of altitude and landforms on some hematological and biochemical parameters. MATERIALS AND METHODS A total of 160 ewes having 3-5 years of age, multiparous, non-pregnant, non-lactating and reared in arid areas of South East Algeria were included. Blood samples were divided acc...
the caspian sea contains great resources of oil and gas. the caspian sea is a 700- mile- long body of water in central asia, land located between azerbaijan, iran, kazakhstan, russia and turkmenistan. iran was challenges and opportunities in the caspian region. key question in this thesis includes three section that first question, opportunities of iran in the caspian region, second question ch...
The atmospheric movement of arid soil can play an important role in the movement of microorganisms attached to soil microparticles. Bacterial community structures in Asian dust collected at Beijing were investigated using the 16S rRNA gene sequence and compared to those in arid soil, a possible source of the dust. Asian dust samples contained 2.5×10(7) to 3.5×10(9) copies of the 16S rRNA gene g...
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