نتایج جستجو برای: soil water content

تعداد نتایج: 1056794  

2014
John D. Hearn Christopher D. Hare Jeffery A. Eichler Michael V. Henley

The effect of soil moisture on chlorine (Cl2) deposition was examined in laboratory chamber experiments at high Cl2 exposures by measuring the concentration of chloride (Cl−) in soil columns. Soil mixtures with varying amounts of clay, sand, and organic matter and with moisture contents up to 20% (w/w) were exposed to ≈3 × 104 ppm Cl2 vapor. For low water content soils, additional water increas...

2014
X. Wang C.-J. Lin X. Feng

A box model for estimating bidirectional air– surface exchange of gaseous elemental mercury (Hg0) has been updated based on the latest understanding of the resistance scheme of atmosphere–biosphere interface transfer. Simulations were performed for two seasonal months to evaluate diurnal and seasonal variation. The base-case results show that water and soil surfaces are net sources, while veget...

2017
Jiping Niu Kai Yang Zejun Tang Yitong Wang

This study investigated the effects of soil crust development on the underlying soil properties. The field sampling work was conducted in June 2016 in the Hobq Desert in Inner Mongolia, North China. Soil crust samples and 0–6, 6–12, 12–18, 18–24, 24–30 cm deep underlying soil samples were taken from five representative areas of different soil crust development stages. All samples were analyzed ...

2006
J. A. SMETHURST

In temperate European climates, the season of peak water demand by vegetation (summer) is out of phase with the season of greatest rainfall (winter). This results in seasonal fluctuations in soil water content and, in clay soils, associated problems of shrinking and swelling that can in turn contribute to strain-softening and progressive slope failure. This paper presents field measurements of ...

2002
Molly S. Costanza-Robinson Mark L. Brusseau

[1] Gas phase miscible displacement experiments were conducted to quantitatively investigate the advective and dispersive contributions to gas phase transport in unsaturated porous media over a range of soil water contents. Furthermore, the independence of measured dispersivity values was evaluated through comparison of nonreactive and reactive tracer transport. Methane was used as a nonreactiv...

2012
Steven R. Evett Nurit Agam William P. Kustas Paul D. Colaizzi Robert C. Schwartz

Diffusive heat flux at the soil surface is commonly determined as a mean value over a time period using heat flux plates buried at some depth (e.g., 5–8 cm) below the surface with a correction to surface flux based on the change in heat storage during the corresponding time period in the soil layer above the plates. The change in heat storage is based on the soil temperature change in the layer...

2006
H. Yang H. Rahardjo E.-C. Leong

This paper presents the laboratory test results of vertical infiltration on two soil columns of finer over coarser soils subject to simulated rainfalls under conditions of no-ponding at the surface and constant head at the bottom. The main objectives were to evaluate the effect of rainfall intensity and duration; and to provide experimental evidence for soil water redistribution and hysteresis....

2003
S. R. Evett

rameterized for a given porous medium by slope and intercept values obtained through field calibration (HigThe neutron thermalization method for soil water content measurenett and Evett, 2002). For probe designs common in the ment is well established as being accurate for deep soil profile measurements. However, the method has been criticized as inaccurate for 1960s, about 95% of the measured s...

2015
Antonino Maltese Fulvio Capodici Giuseppe Ciraolo Goffredo La Loggia

Knowledge of soil water content plays a key role in water management efforts to improve irrigation efficiency. Among the indirect estimation methods of soil water content via Earth Observation data is the triangle method, used to analyze optical and thermal features because these are primarily controlled by water content within the near-surface evaporation layer and root zone in bare and vegeta...

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