scholarly journals Adsorption/Desorption Patterns of Selenium for Acid and Alkaline Soils of Xerothermic Environments

Environments ◽  
2020 ◽  
Vol 7 (10) ◽  
pp. 72
Author(s):  
Ioannis Zafeiriou ◽  
Dionisios Gasparatos ◽  
Ioannis Massas
Keyword(s):  
Metal Oxides ◽  
Ammonium Oxalate ◽  
Acid Soils ◽  
Organic Content ◽  
Soil Electrical Conductivity ◽  
Alkaline Soils ◽  
Surface Complexes ◽  
Two Parameters ◽  
Soil Organic Content ◽  
Adsorption Desorption

Selenium adsorption/desorption behavior was examined for eight Greek top soils with different properties, aiming to describe the geochemistry of the elements in the selected soils in terms of bioavailability and contamination risk by leaching. Four soils were acid and four alkaline, and metal oxides content greatly differed between the two groups of soils. The concentrations of Se(IV) used for the performed adsorption batch experiments ranged from 1 to 50 mg/L, while the soil to solution ratio was 1 g/0.03 L. Acid soils adsorbed significantly higher amounts of the added Se(IV) than alkaline soils. Freundlich and Langmuir equations adequately described the adsorption of Se(IV) in the studied soils, and the parameters of both isotherms significantly correlated with soil properties. In particular, both KF and qm values significantly positively correlated with ammonium oxalate extractable Fe and with dithionite extractable Al and Mn, suggesting that amorphous Fe oxides and Al and Mn oxides greatly affect exogenous Se(IV) adsorption in the eight soils. These two parameters were also significantly negatively correlated with soil electrical conductivity (EC) values, indicating that increased soluble salts concentration suppresses Se(IV) adsorption. No significant relation between adsorbed Se(IV) and soil organic content was recorded. A weak salt (0.25 M KCl) was used at the same soil to solution ratio to extract the amount of the adsorbed Se(IV) that is easily exchangeable and thus highly available in the soil ecosystem. A much higher Se(IV) desorption from alkaline soils was observed, pointing to the stronger retention of added Se(IV) by the acid soils. This result implies that in acid soils surface complexes on metal oxides may have been formed restricting Se desorption.

Phosphorus effect on Zn adsorption–desorption kinetics in acid soils

Chemosphere ◽  
2011 ◽  
Vol 83 (7) ◽  
pp. 1028-1034 ◽  
Author(s):  
Cristina Pérez-Novo ◽  
David Fernández-Calviño ◽  
Alipio Bermúdez-Couso ◽  
José E. López-Periago ◽  
Manuel Arias-Estévez
Keyword(s):  
Acid Soils ◽  
Desorption Kinetics ◽  
Adsorption Desorption

Biogeochemical indicators to evaluate pollutant removal efficiency in constructed wetlands

1997 ◽  
Vol 35 (5) ◽  
pp. 1-10 ◽  
Author(s):  
K. R. Reddy ◽  
E. M. D'Angelo
Keyword(s):  
Microbial Biomass ◽  
Removal Efficiency ◽  
Nitrate Removal ◽  
Oxygen Demand ◽  
Acid Soils ◽  
Pollutant Removal ◽  
Alkaline Soils ◽  
Organic C ◽  
Wetland Treatment ◽  
Biogeochemical Indicators

Wetlands support several aerobic and anaerobic biogeochemical processes that regulate removal/retention of pollutants, which has encouraged the intentional use of wetlands for pollutant abatement. The purpose of this paper is to present a brief review of key processes regulating pollutant removal and identify potential indicators that can be measured to evaluate treatment efficiency. Carbon and toxic organic compound removal efficiency can be determined by measuring soil or water oxygen demand, microbial biomass, soil Eh and pH. Similarly, nitrate removal can be predicted by dissolved organic C and microbial biomass. Phosphorus retention can be described by the availability of reactive Fe and Al in acid soils and Ca and Mg in alkaline soils. Relationships between soil processes and indicators are useful tools to transfer mechanistic information between diverse types of wetland treatment systems.

Preferential nitrate immobilization in alkaline soils

Soil Research ◽  
1992 ◽  
Vol 30 (5) ◽  
pp. 737 ◽  
Author(s):  
IJ Rochester ◽  
GA Constable ◽  
DA Macleod
Keyword(s):  
Acid Soil ◽  
Nitrification Inhibitor ◽  
Biological Significance ◽  
Nitrate Assimilation ◽  
Acid Soils ◽  
Ammonium Assimilation ◽  
Potassium Nitrate ◽  
Alkaline Soil ◽  
Alkaline Soils ◽  
Nitrate Immobilization

The literature pertaining to N immobilization indicates that ammonium is immobilized in preference to nitrate. Our previous research in an alkaline clay soil has indicated substantial immobilization of nitrate. To verify the preference for immobilization of nitrate or ammonium by the microbial biomass in this and other soil types, the immobilization of ammonium and nitrate from applications of ammonium sulfate and potassium nitrate following the addition of cotton crop stubble was monitored in six soils. The preference for ammonium or nitrate immobilization was highly correlated with each soil's pH, C/N ratio and its nitrification capacity. Nitrate was immobilized in preference to ammonium in neutral and alkaline soils; ammonium was preferentially immobilized in acid soils. No assimilation of nitrate (or nitrification) occurred in the most acid soil. Similarly, little assimilation of ammonium occurred in the most alkaline soil. Two physiological pathways, the nitrate assimilation pathway and the ammonium assimilation pathway, appear to operate concurrently; the dominance of one pathway over the other is indicated by soil pH. The addition of a nitrification inhibitor to an alkaline soil enhanced the immobilization of ammonium. Recovery of 15N confirmed that N was not denitrified, but was biologically immobilized. The immobilization of 1 5 ~ and the apparent immobilization of N were similar in magnitude. The identification of preferential nitrate immobilization has profound biological significance for the cycling of N in alkaline soils.

scholarly journals Studi Kemampuan Adsorpsi Ion Logam Cr6+ oleh Tanah Vulkanik “Studi Kasus Wilayah Industri Penyamakan Kulit, Garut”

2020 ◽  
Vol 21 (1) ◽  
pp. 125-130
Author(s):  
Nyoman Sumawijaya ◽  
Asep Mulyono ◽  
Anna Fadliah Rusydi
Keyword(s):  
Adsorption Capacity ◽  
Waste Treatment ◽  
Liquid Waste ◽  
Freundlich Isotherm ◽  
Organic Content ◽  
Maximum Adsorption Capacity ◽  
Soil Media ◽  
Pass Through ◽  
Soil Organic Content ◽  
The Impact

ABSTRACTThe leather tanning industry in Sukaregang, Garut Regency, produces liquid waste containing Chromium and is discharged directly into the Ciwalen River without a waste treatment process. The content of Cr6+ as metal ions in the waste can also contaminating groundwater. The movement of Cr6+ will pass through the soil media before entering to the groundwater wells. The capability of the soil to adsorb the contaminant will reduce the impact on groundwater. The purpose of this study was to determine the ability of the soil in adsorbing and inhibiting the movement of Cr6+ into groundwater. The study was carried out at Sukaregang, Garut Regency and conducting adsorption experiments with a batch system. The analysis was carried out using the Langmuir and Freundlich isotherm model. The experimental results showed that Cr6+ adsorbed ranged from 38% to 57% of the initial concentration. The results from Langmuir Isotherm were: the distribution coefficient (Kads) was 0.45 L/mg and the maximum adsorption capacity (qm) was 2.44 mg/100g sorbent with R2 = 0.959 and Freundlich Isotherm was: qm was 2,86 mg/100g sorbent and Kads was 0,35 L/mg with R2 = 0,860. This large adsorption capacity is caused by soil texture and soil organic content. The soil in Sukaregang tanning industries has a high adsorption capacity towards Cr6+ contaminants.Keywords: adsorption, chromium, Cr6+, contaminant, volcanic soil, GarutABSTRAKIndustri penyamakan kulit di wilayah Sukaregang, Kabupaten Garut, menghasilkan limbah cair yang mengandung Kromium dan dibuang ke Sungai Ciwalen tanpa proses pengolahan limbah. Kandungan ion logam Cr6+ pada limbah dapat mencemari air tanah. Pergerakan ion logam Cr6+ akan melalui media tanah sebelum memasuki sumur-sumur penduduk. Beberapa jenis tanah mempunyai kemampuan untuk mengadsorpsi ion pencemar sehingga tidak semua limbah yang meresap ke dalam tanah mencemari air tanah. Tujuan dari penelitian ini adalah untuk mengetahui peranan tanah dalam menghambat pergerakan ion logam Cr6+ ke dalam air tanah. Penelitian dilaksanakan dengan pengambilan sampel tanah di daerah Sukaregang, Garut, dan melakukan percobaan adsorpsi dengan sistem batch. Sementara analisis dilakukan dengan menggunakan model isotherm Langmuir dan Freundlich. Hasil percobaan menunjukkan konsentrasi Cr6+ yang teradsorpsi berkisar 38 – 57 % dari konsentrasi awal. Kads sebesar 0,45 L/mg dan qm sebesar 2,44 mg/100g tanah dengan nilai R2 = 0,959 menggunakan isoterm Langmuir dan isoterm Freundlich memberikan nilai qm sebesar 2,86 mg/100 g sorbent dan Kads sebesar 0,35 L/mg dengan R2 = 0,860. Tingginya daya adsorpsi ini disebabkan oleh tekstur tanah dan kandungan bahan organik. Tanah di wilayah penelitian memiliki daya adsorpsi yang besar terhadap kontaminan Cr6+.Kata kunci: adsorpsi, kromium, Cr6+, kontaminan, tanah vulkanik, Garut

Identifying the intensity of crop husbandry practices on the basis of weed floras

1999 ◽  
Vol 94 ◽  
pp. 167-189 ◽  
Author(s):  
Glynis Jones ◽  
Amy Bogaard ◽  
Paul Halstead ◽  
Michael Charles ◽  
Helen Smith
Keyword(s):  
Ecological Study ◽  
Organic Content ◽  
Small Scale ◽  
Social Significance ◽  
Weed Flora ◽  
Weed Seeds ◽  
Historical Times ◽  
Size Type ◽  
Crop Husbandry ◽  
Soil Organic Content

A question of broad economic and social significance is the extent to which farming in prehistoric times, and perhaps even in historical times, was characterised by cultivation on a small scale and with intensive methods. Archaeobotanically, a distinction may be possible between intensive and extensive cultivation on the basis of the weed seeds associated with ancient grain samples. To this end, an ecological study was carried out in central Ewia of the weeds of winter-sown pulses grown both intensively in gardens and extensively in fields. The recorded weed flora was demonstrably influenced by relevant husbandry variables, such as method of tillage (with hoe or plough), weeding, manuring and soil organic content. The closest correspondence, however, was with the size, type and location of cultivated plots, suggesting that the weed flora was determined by a combination of these husbandry variables. In conclusion, the potential is briefly discussed of disentangling these variables for application in an archacobotanical context.

Altitudinal soil and vegetation transitions in alpine desert, the Central Great Caucasus, Georgia

2020 ◽  
Author(s):  
Tamar Jolokhava ◽  
Zaal Kikvidze
Keyword(s):  
Soil Ph ◽  
Strong Dependence ◽  
Gradient Methods ◽  
Abundant Species ◽  
Organic Content ◽  
Slope Aspect ◽  
High Mountain ◽  
Available Nutrients ◽  
Mountain Systems ◽  
Soil Organic Content

<p>Alpine deserts are noteworthy habitats in high mountain systems such as the Caucasus. However, very little is known on the soil properties in these habitats. Another unexplored question is the transition between subnival (lower part of alpine desert) and nival (upper part of alpine desert) belts. We studied soils and vegetation in an alpine desert along its practically entire elevation range (3000-4000 m a.s.l.) on two contrasting slope aspects (north vs south) of Mt. Kazbegi, the Central Great Caucasus, Georgia. Vegetation with standardized stratified-random design and collected soil samples for measuring pH, soil organic content (SOM) and available nutrients (N, P, K) were sampled; the collected data were analyzed with direct gradient methods as well as multivariate ordination. 63 species were recorded and, as expected, strong dependence of species distribution on elevation and between slopes was documented. We found that soil pH increased monotonically with altitude on both N and S slopes and reached alkaline values with bare bedrock. The changes were steeper on the northern slope than on the southern slope, and, remarkably, many relatively abundant species changed their preference to slope aspect from N to S in parallel with the increasing difference in soil pH.  We suspect that the pH  observed shift in slope preference, at least in part, can be explained by the effect of different soil pH. As for SOM, it decreased from very low values to zero at the higher altitudes, whilst available nutrients dropped dramatically and predominantly multispecific vegetation patches characteristic for subnival belt changed abruptly to monospecific patches or solitary plants typical for nival belt. These abrupt changes occurred at 3400-3500m a.s.l., and most probably indicate a vegetation switch between the mentioned belts on Mt. Kazbegi.</p><p>Overall, our results show two characteristics of alpine desert vegetation and soils, which have not been documented to date: (1) an unexpected change of slope preference of many relatively abundance plants which probably is associated with different soil pH profiles on N and S slopes, and (2) a vegetation switch between subnival and nival belts that occurs at relatively lower elevations than expected from the concept of alpine-nival ecotone.</p>

Adaptation and potential contribution of temperate perennial legumes to the southern Australian wheatbelt: a review

2003 ◽  
Vol 43 (1) ◽  
pp. 1 ◽  
Author(s):  
B. S. Dear ◽  
G. A. Moore ◽  
S. J. Hughes
Keyword(s):  
Current Knowledge ◽  
Acid Soils ◽  
Potential Contribution ◽  
Alkaline Soils ◽  
Dryland Salinity ◽  
Annual Crops ◽  
Medicago Sativa L ◽  
Perennial Legumes ◽  
Herbaceous Perennial ◽  
Pasture Plants

Deep-rooted perennial pasture plants can play an important role in solving the environmental problems of rising watertables, dryland salinity and soil acidification in the wheatbelt of southern Australia. These problems are attributed to the extensive clearing of perennial native vegetation and its replacement with shallow-rooted winter-growing annual crops and pastures. Deep-rooted, herbaceous perennial legumes, particularly lucerne (Medicago sativa L.), are seen as making an increasing contribution in the cropping zones where high rates of symbiotic nitrogen fixation and increased water use are high priorities. This paper reviews the current use and the potential of a range of temperate perennial legumes for the wheatbelt of southern Australia. The genera examined include Medicago, Hedysarum, Trifolium, Onobrychis, Lotus, Galega, Astragalus, Lathyrus, Anthyllis, Psoralea, Dorycnium, Lespedeza and Securigera. There is considerable scope to expand the use of lucerne; however, there is also a need for alternative perennial species to increase biodiversity and to fill niches where lucerne is less suited. Based on current knowledge, the species with the most promise to complement lucerne include sainfoin (Onobrychis viciifolia Scop.) and sulla (Hedysarum coronarium L.) on alkaline soils, strawberry clover (Trifolium fragiferum L.) in wet or mildly saline niches and Lotus and Dorycnium spp. on waterlogged and/or acid soils.

Erratic nodulation and nitrogen fixation in field-grown pigeonpea [Cajanus cajan (L.) Millsp.]

1991 ◽  
Vol 31 (5) ◽  
pp. 653 ◽  
Author(s):  
J Brockwell ◽  
JA Andrews ◽  
RR Gault ◽  
LG Gemell ◽  
GW Griffith ◽  
...  
Keyword(s):  
N2 Fixation ◽  
Cajanus Cajan ◽  
New South ◽  
Acid Soils ◽  
Grain Legume ◽  
Alkaline Soils ◽  
Naturally Occurring ◽  
South Wales ◽  
Series Of Experiments ◽  
Experimental Findings

Following numerous reports of nodulation failures in pigeonpea [Cajanus cajan (L.) Millsp.] crops in New South Wales, a series of experiments was conducted in glasshouses and at 6 locations in the field. When inoculated seed was grown in moist vermiculite or in sand beds in the glasshouse, pigeonpea nodulated, and fixed N2, normally; but at 3 sites in the field, we could detect neither nodulation nor N2 fixation, despite adequate inoculation or a population of suitable rhizobia in the soil. At another site there was only sporadic occurrence of effective nodules. Nitrogen was fixed at 2 of the 3 field sites on acid soils, but at 1 site it appeared that nodulation was due to a naturally occurring population of soil rhizobia and not to the inoculant. When comparisons were made, pigeonpea was invariably inferior to symbiotically related legumes, cowpea and adzuki bean, in nodulation and N2 fixation. This inferiority was associated with substantially poorer rhizobial colonisation of pigeonpea rhizospheres. The experimental findings confirmed the anecdotal evidence that pigeonpea is an erratically nodulating grain legume on neutral and alkaline soils.

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