نتایج جستجو برای: disturbing the upper soil layers

تعداد نتایج: 16137039  

2006

Changes in the carbon stocks of stem biomass, organic layers and the upper 50 cm of the mineral soil during succession and afforestation of spruce (Picea abies) on former grassland were examined along six chronosequences in Thuringia and the Alps. Three chronosequences were established on calcareous and three on acidic bedrocks. Stand elevation and mean annual precipitation of the chronosequenc...

Journal: :Tree physiology 2002
Fabian G Scholz Sandra J Bucci Guillermo Goldstein Frederick C Meinzer Augusto C Franco

The magnitude and direction of water transport by the roots of eight dominant Brazilian savanna (Cerrado) woody species were determined with a heat pulse system that allowed bidirectional measurements of sap flow. The patterns of sap flow observed during the dry season in species with dimorphic root systems were consistent with the occurrence of hydraulic redistribution of soil water, the movem...

Journal: :آب و خاک 0
قربانی دشتکی قربانی دشتکی همایی همایی مهدیان مهدیان

abstract infiltration is a significant process which controls the fate of water in the hydrologic cycle. the direct measurement of infiltration is time consuming, expensive and often impractical because of the large spatial and temporal variability. artificial neural networks (anns) are used as an indirect method to predict the hydrological processes. the objective of this study was to develop ...

Journal: :Remote Sensing 2013
Pei Leng Xiaoning Song Zhao-Liang Li Yawei Wang

Land surface soil moisture (SSM) is crucial in research and applications in hydrology, ecology, and meteorology. A novel SSM retrieval model, based on the diurnal cycles of land surface temperature (LST) and net surface shortwave radiation (NSSR), has recently been reported. It suggests a promising avenue for the retrieval of regional SSM using LST and NSSR derived from geostationary satellites...

Journal: :Trends in ecology & evolution 1998
J L Horton S C Hart

Hydraulic lift is the process by which some deep-rooted plants take in water from lower soil layers and exude that water into upper, drier soil layers. Hydraulic lift is beneficial to the plant transporting the water, and may be an important water source for neighboring plants. Recent evidence shows that hydraulically lifted water can promote greater plant growth, and could have important impli...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور استان مازندران - دانشکده ریاضی 1390

abstract this thesis includes five chapter : the first chapter assign to establish fuzzy mathematics requirement and introduction of liner programming in thesis. the second chapter we introduce a multilevel linear programming problems. the third chapter we proposed interactive fuzzy programming which consists of two phases , the study termination conditions of algorithm we show a satisfac...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده شیمی 1389

in this thesis, a new optically active poly(amide-imide) (pai) was synthesized by the indirect polycondensation reaction of the l-phenylalanine based diacid chloride and 4,4?-diaminodiphenylether in the presence of triethylamine in n-methyl-2-pyrrolidone. the formation of pai was confirmed by ftir, 1h nmr and elemental analysis. in next step, the surface of titanium dioxide (tio2) nanoparticles...

2014
A. Navas

Natural gamma-emitting radionuclides (U, Ra, Th, Pb) and selected major and trace elements (Ca, K, Mg, Na, Fe, Al, Mn, Pb, Ba, Zn, Sr, Li, Co, Ni, Cu, Cr, Cd) were determined in a soil toposequence along a mountain slope of the Tertiary Flysch landscapes in the Central Spanish Pyrenees. A variety of basic properties were also measured from the soil profiles. Mean radioisotope activities (Bq kg ...

Abstract Steel sheet pile walls are being widely used in civil engineering projects for support systems. Soil is not uniform in depth, sometimes may be exit loose or soft soil layer in various depth. This issue can cause different effects on ground surface displacements, forces and moments acting on sheet piles and struts during excavation procedure, compared with status that soil is uniform...

2015
Ivan H. Tuf Vojtěch Chmelík Igor Dobroruka Lucie Hábová Petra Hudcová Jan Šipoš Slavomír Stašiov

Some species of centipedes and millipedes inhabit upper soil layers exclusively and are not recorded by pitfall trapping. Because of their sensitivity to soil conditions, they can be sampled quantitatively for evaluation of soil conditions. Soil samples are heavy to transport and their processing is time consuming, and such sampling leads to disturbance of the soil surface which land-owners do ...

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