نتایج جستجو برای: spatial variability

تعداد نتایج: 481155  

Journal: :journal of agricultural science and technology 2010
a. r. vaezi h. a. bahrami s. h. r. sadeghi m. h. mahdian

the soil erodibility factor varies spatially according to variations of some soil properties on the surface. this study was carried out to compare spatial variability of the soil erodibility factor as estimated and measured using the usle. the study was conducted in an agricultural zone with an area of in 900 km2 in hashtrood, northwestern iran. in the study area, 36 square grids with a dimensi...

Journal: :caspian journal of environmental sciences 2010
r. akhavan

estimating the amount of variation due to spatial dependence at different scales provides a basis for designing effective experiments. accurate knowledge of spatial structures is needed to inform silvicultural guidelines and management decisions for long term sustainability of forests. furthermore, geostatistics is a useful tool to describe and draw map the spatial variability and estimation of...

Journal: :آب و خاک 0
مجتبی رضایی ناصر دواتگر خسرو تاجداری بهروز ابولپور

abstract guilan is a famous province in growing rice in iran. recently, due to shortage of water, farmers' desire to use groundwater in order to grow rice in northern part of iran has been increasing rapidly. the fact that rice is sensitive to water quality, caused concern about rice cultivation sustainability in the area, especially in drought years. this study was done to investigate the spat...

صیاد, احسان, غلامی, شایسته,

In Zagros forest ecosystem, spatial variability of soil and vegetation properties are controlled by series of physical and biological parameters including topographical and anthropogenic factors. Distribution patterns of these properties are greatly variable. In the current study, geostatistics and fractal theory were used to assess the spatial variability of tree canopy and soil bulk density i...

Journal: :آب و خاک 0
مریم محسنی سجادی مجید افیونی حسین خادمی سید اسداله محسنی موحد شمس اله ایوبی

abstract fluoride (f-) is an essential element for human and some animals. the fluoride concentration in irrigation water is an important index for water quality. the objective of the present study was to determine spatial variability of fluoride in groundwater and soils of some areas in arak plain. therefore, during two seasons, autumn (2007) and the end of spring (2008), 87 and 92 water sampl...

Journal: :آب و خاک 0
شایسته غلامی سید محسن حسینی جهانگرد محمدی عبدالرسول ماهینی

abstract soil invertebrate and their spatial pattern are affected strongly by environmental factors. spatial variability of soil properties is one of the most important reasons of the macrofauna variability. this study was conducted to investigate the spatial variability of soil properties and soil macrofauna biomass in the riparian forest landscape of karkhe river. soil macro fauna were sample...

Journal: :تحقیقات مهندسی کشاورزی 0
فاطمه محرابی کارشناسی ارشد مهندسی آبیاری و زهکشی علیرضا سپاسخواه استاد بخش مهندسی آب دانشکده کشاورزی، دانشگاه شیراز

study of the spatial variability of infiltration characteristics is essential to estimating infiltration parameters on a local scale. the objectives of the present study were to scale the parameters of a philip two-term model for infiltration and survey the variability of infiltration characteristics geostatistically using wastewater in the bajgah catchment. infiltration was measured at 30 poin...

Journal: :caspian journal of environmental sciences 2010
r. akhavan

this research was conducted to investigate spatial variability and estimate tree attributes in a plantation forest in the caspian region of iran using geostatistical analysis. sampling was performed based on a 50m?125m systematic grid in a maple stand (acer velutinum boiss) 18 years of age using circular samples of 200m2 area. totally, 96 sample plots were measured in 63 hectares and 14.25 hect...

Estimating the amount of variation due to spatial dependence at different scales provides a basis for designing effective experiments. Accurate knowledge of spatial structures is needed to inform silvicultural guidelines and management decisions for long term sustainability of forests. Furthermore, geostatistics is a useful tool to describe and draw map the spatial variability and estimation o...

جهانگرد محمدی, , فایز رئیسی گهرویی, ,

Knowledge of the spatial dependency of soil properties, sensitive to grazing systems, is important from an ecosystem protection point of view. In the current study, geostatistical methods and fractal concepts have been used in order to characterize the impact of long-term grazing exclusion on the spatial variability of some soil chemical parameters including organic matter, total nitrogen, avai...

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