نتایج جستجو برای: soil chemistry

تعداد نتایج: 287163  

2007
Kyungsoo Yoo Ronald Amundson Arjun M. Heimsath William E. Dietrich George H. Brimhall

[1] We developed a process-oriented hillslope soil mass balance model that integrates chemical and physical processes within hillslope soils. The model explicitly factors that soil chemical weathering at any hillslope position is related to the flux of soil eroded from upslope as well as soil production from underlying bedrock. The model was merged with measurements of soil elemental chemistry ...

2015
P Y Oikawa C Ge J Wang J R Eberwein L L Liang L A Allsman D A Grantz G D Jenerette

Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate so...

2016
Pichu Rengasamy Matthew Gilliham

The yield response of various crops to salinity under field conditions is affected by soil processes and environmental conditions. The composition of dissolved ions depend on soil chemical processes such as cation or anion exchange, oxidation-reduction reactions, ion adsorption, chemical speciation, complex formation, mineral weathering, solubility, and precipitation. The nature of cations and ...

Journal: :international journal of environmental research 0

a total of 148 groundwater samples were collected from bore wells from thirumanimuttar sub-basin for two seasons to identify major geochemical process activated to alter groundwater chemistry. the study revealed relationships with the lithology and anthropogenic process. groundwater in the region was dominated by na – ca – mg and cl and hco3 types. the (ca +mg) versus tz+ plot for both seas...

Journal: :Environmental science & technology 2007
Hana Santrůcková Jirí Santrůcek Jirí Setlík Miroslav Svoboda Jirí Kopácek

The Bohemian Forest was exposed to high levels of sulfur and nitrogen deposition during the last century. The change in acid deposition caused a rapid decline in pH and increase in Al concentrations of soil solutions since the 1950s. A possible negative effect of soil chemistry on growth of Norway spruce tree has been studied using the 13C isotopic signal and chemistry of the tree rings. Tree r...

2002
D. L. Suarez

Numerous models have been developed for predicting major ion chemistry in the soil zone and in recharge to groundwater. Soils that contain CaCO, are prevalent in arid and semiarid regions, as well as in humid and temperate regions that have been glaciated or contain carbonate bedrock. Under these conditions, carbonate-solution reactions and ion exchange are the dominant chemical processes. In t...

2005
J. A. Hurowitz S. M. McLennan N. J. Tosca R. E. Arvidson J. R. Michalski D. W. Ming C. Schröder S. W. Squyres

[1] Experimental data for alteration of synthetic Martian basalts at pH = 0–1 indicate that chemical fractionations at low pH are vastly different from those observed during terrestrial weathering. Rock surface analyses from Gusev crater are well described by the relationships apparent from low-pH experimental alteration data. A model for rock surface alteration is developed, which indicates th...

Journal: :Inhalation toxicology 2009
Johann P Engelbrecht Eric V McDonald John A Gillies R K M Jay Jayanty Gary Casuccio Alan W Gertler

The purpose of the Enhanced Particulate Matter Surveillance Program was to provide scientifically founded information on the chemical and physical properties of dust collected during a period of approximately 1 year in Djibouti, Afghanistan (Bagram, Khowst), Qatar, United Arab Emirates, Iraq (Balad, Baghdad, Tallil, Tikrit, Taji, Al Asad), and Kuwait (northern, central, coastal, and southern re...

Journal: :Environmental pollution 2000
Y Dong L Q Ma R D Rhue

It is well documented that Pb solubility may be related to Fe chemistry in soils and enhanced Pb solubility may occur under certain reducing conditions; however, quantification of such relationships is unavailable. Based on metal classification, Pb (II) and Fe (II) are similar in some chemical characteristics. Thus, competition between Pb and Fe for ligands in soils may be important in determin...

A. Lakhdar, Ch. Abdelly F. Montemurro, T. Ghnaya Y. Ouni

The environmental, social and economical reasons indicate that the conventional agriculture constitute a continuous pressure contributing to the progressive worsening of environmental conditions, especially by an increasing apply high level of inputs. In this matter, the increasing use of saline irrigation water is one of the main factors resulting in salt accumulation in the plant rhizosp...

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