نتایج جستجو برای: 20 cm in soil layer in totally
تعداد نتایج: 17154190 فیلتر نتایج به سال:
The bacterial community composition of the active layer (0-45 cm) of a permafrost-affected tundra soil was analysed by fluorescence in situ hybridisation (FISH). Arctic tundra soils contain large amounts of organic carbon, accumulated in thick soil layers and are known as a major sink of atmospheric CO(2). These soils are totally frozen throughout the year and only a thin active layer is unfroz...
soil enzyme activities are considered as one of the most important biological indicators and reflect the soil quality and fertility. current study was conducted to investigate the relationship between urease, invertase, alkaline phosphatase and aryl sulphatase activities of two histosols (located in kerman and shahrekord provence) and some of the soil chemical and biological properties. soil sa...
this study analyzed the relationship between the vertical distribution of root biomass and soil organic carbon (soc)content in the arid shrub lands of semnan province in iran. three sites were selected based on differences in canopy coverof artemisia sieberi (5%, 10% and 15%). average density of shrubs, root biomass and soc were determined at differentdepths (0-20, 20-40, 40-60, 60-80 cm) in 20...
Over three million hectares of salt-affected soils characterized with high salinity and sodicity caused serious land degradation in Songnen Plain, northeast China. Soil salinity–sodicity heterogeneous distribution under microtopography is usually influenced by several environmental factors. The side direction movement of soil water driven by water from depression is the key factor that aggravat...
1- in a search directed to the reaction of compound)23(the cycloaddition reaction of 1,3- diphenylisobenzofurane)14(with p-benzoquinone)19(,followed by addition of cyclopentadiene was carried out.the specific spacial stracture of its ir,nmr,mass spectra. 2- in another attempt the kinetic stability and behavior of compounds)20(and)23(was studied.the main subject of this study was the highly reve...
determination of the relationships between soil and plant cover indispensible in the in planning and managementof the arid regions, the aim being to revitalize plant cover, conserve soil and to combat desertification. among factorsaffecting plant cover, particularly in arid and semiarid areas are soil traits. during the present study, the effect ofhaloxylon aphyllum cultivation on soil physioch...
In this research, we estimated soil shallow depths temperatures using regression methods (Linear and Polynomial). The soil temperatures at soil depths (5, 10, 20, 30, 50 and 100 cm) were correlated with meteorological parameters. For this purpose, temperature data of Hamedan station (in the period 1992-2005) were employed. Soil temperature data were measured on a daily basis at 3 PM, 9 PM and 3...
this study aimed to investigate the effect of animal grazing on soil seed bank characteristics in the northern slopes of alborz. for this purpose, soil seed bank characteristics were compared between grazed and ungrazed areas. therefore, four transects perpendicular to the sides of exclosure inside and outside of it were established. then soil samples were collected within 28 plots inside and 2...
Organic carbon pools and carbon lability directly affect soil biological, physical and chemical characteristics. Besides, capacity of self-organization of soil is related to the organic carbon pools. Sand size fraction (> 50 µm) organic matter is more labile than silt+clay size fraction organic matter. Assessment of this organic carbon variation can be a suitable index to determine soil quality...
the introduction of canola (oilseed rape; brassica napus l.) as a new source of vegetable oil production in iran prompts evaluation of the performance of this crop under different tillage systems. a field experiment was conducted to determine the impact of depth and intensity of tillage on soil physical properties, crop establishment and yield of irrigated winter canola in a loam soil (typic ha...
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