نتایج جستجو برای: free throughfall coefficient

تعداد نتایج: 674925  

Journal: :journal of agricultural science and technology 2015
s. m. m. sadeghi p. attarod t. g. pypker

we estimated the rainfall interception loss (i), canopy storage capacity (s), the ratio of mean evaporation rate from the wet canopy () over the mean rainfall intensity () (mm h-1) (), and free throughfall coefficient (p) in a fraxinus rotundifolia mill. stand located in an afforested park land in a semiarid region of iran. for each storm event, i was calculated as the gross rainfall (gr) minus...

2002
K. J. Raat

This study focuses on spatial variability of throughfall water and chemistry and forest floor water content within a Douglas fir (Pseudotsuga menziesii, Franco L.) forest plot. Spatial patterns of water and chemistry (NH4 +, NO3 -, SO4 2-, Cl-, Mg2+, Ca2+, Na+ and K+) were compared and tested for stability over time. The spatial coefficient of variation (CV) was between 18 and 26% for amounts o...

2014
lexander Zimmermann Beate Zimmermann

A wide range of basic and applied problems in water resources research requires high-quality estimates of the spatial mean of throughfall. Many throughfall sampling schemes, however, are not optimally adapted to the system under study. The application of inappropriate sampling schemes may partly reflect the lack of generally applicable guidelines on throughfall sampling strategies. In this stud...

2004
Zhenmin Tang Mary A. Sword Sayer Jim L. Chambers James P. Barnett

Few studies have examined the combined effects of nutrition and water exclusion on the canopy physiology of mature loblolly pine (Pinus taeda L.). Understanding the impacts of forest management on plantation productivity requires extensive research on the relationship between silvicultural treatments and environmental constraints to growth. We studied the physiological responses of 18-year-old ...

2007
Wolfgang Wanek Julia Hofmann Ilka C. Feller

r a 200 .012 : +43 1 anek@u Summary Bulk precipitation, throughfall and stemflow were collected to study anthropogenic effects on above-ground nutrient cycling in an off-shoremangrove forest (Rhizophora mangle L.) on Twin Cays, Belize. Samples were collected in a nitrogen limited fringe and phosphorus limited dwarf zone, and from an adjacent nitrogen fertilized fringe and a phosphorus fertilize...

P Attarod, S.M.M Sadeghi T.G Pypker V Bayramzadeh

The Persian oak, Quercus brantii, trees in the Zagros region of Western Iran have been in decline since 2000. The decline is assumed to be highly connected with changes in meteorological parameters. Our objectives were to quantify the long-term trends in meteorological parameters and reference evapotranspiration (ET0) in the Zagros region and estimate ecohydrological parameters highly affected ...

2009
David E. Pelster Randall K. Kolka Ellie E. Prepas

Nitrate, ammonium, total dissolved nitrogen (TDN), dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) concentrations and flux were measured for one year in bulk deposition and throughfall from three stand types (upland deciduous, upland conifer and wetland conifer) on the Boreal Plain, Canada. Annual (November 2006 to October 2007water year) flux rates in bulk depositionwere 80...

Journal: :Journal of environmental quality 2004
Mark E Fenn Mark A Poth

Conventional throughfall collection methods are labor intensive and analytically expensive to implement at broad scales. This study was conducted to test an alternative approach requiring infrequent sample collection and a greatly reduced number of chemical analyses. The major objective of the study was to determine the feasibility of using ion exchange resin (IER) to measure N deposition in th...

2010
L. Gandois

Atmospheric inputs of selected Trace Metals (TM: Cd, Cu, Ni, Pb, Sb, Zn, as well as Al, Fe and Mn) were studied on six forested sites in France. In order to evaluate canopy interaction with atmospheric inputs, TM were measured in both Open Field Bulk Deposition (BD) and Throughfall (TF). Anthropogenic contribution to BD composition is high for Zn, Cd and Sb, reflecting actual TM emissions trend...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تهران 1370

the subjects of the study are only the tefl teachers and students at gilan university. to obtain the desired data, a questionnaire which was based on the theories and disecussions gathered, was used as the main data gathering instrument. to determine the degree of relationship between variables, covariance and pearson product moment correlation coefficient were the formulas applied. the data we...

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