scholarly journals Geochemical Modeling of Trivalent Chromium Migration in Saline-Sodic Soil during Lasagna Process: Impact on Soil Physicochemical Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-20 ◽  
Author(s):  
Salihu Lukman ◽  
Alaadin Bukhari ◽  
Muhammad H. Al-Malack ◽  
Nuhu D. Mu’azu ◽  
Mohammed H. Essa
Keyword(s):  
Physicochemical Properties ◽  
Soil Ph ◽  
Geochemical Modeling ◽  
Buffering Capacity ◽  
Polarity Reversal ◽  
Reversal Rate ◽  
Voltage Gradient ◽  
Sodic Soil ◽  
Geochemical Properties ◽  
And Migration

Trivalent Cr is one of the heavy metals that are difficult to be removed from soil using electrokinetic study because of its geochemical properties. High buffering capacity soil is expected to reduce the mobility of the trivalent Cr and subsequently reduce the remedial efficiency thereby complicating the remediation process. In this study, geochemical modeling and migration of trivalent Cr in saline-sodic soil (high buffering capacity and alkaline) during integrated electrokinetics-adsorption remediation, called the Lasagna process, were investigated. The remedial efficiency of trivalent Cr in addition to the impacts of the Lasagna process on the physicochemical properties of the soil was studied. Box-Behnken design was used to study the interaction effects of voltage gradient, initial contaminant concentration, and polarity reversal rate on the soil pH, electroosmotic volume, soil electrical conductivity, current, and remedial efficiency of trivalent Cr in saline-sodic soil that was artificially spiked with Cr, Cu, Cd, Pb, Hg, phenol, and kerosene. Overall desirability of 0.715 was attained at the following optimal conditions: voltage gradient 0.36 V/cm; polarity reversal rate 17.63 hr; soil pH 10.0. Under these conditions, the expected trivalent Cr remedial efficiency is 64.75 %.

scholarly journals Integrated Electrokinetics-Adsorption Remediation of Saline-Sodic Soils: Effects of Voltage Gradient and Contaminant Concentration on Soil Electrical Conductivity

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Mohammed Hussain Essa ◽  
Nuhu Dalhat Mu’azu ◽  
Salihu Lukman ◽  
Alaadin Bukhari
Keyword(s):  
Electrical Conductivity ◽  
Contaminated Soils ◽  
Influential Factors ◽  
Polarity Reversal ◽  
Reversal Rate ◽  
Voltage Gradient ◽  
Contaminant Concentration ◽  
Soil Electrical Conductivity ◽  
Sodic Soils

In this study, an integrated in situ remediation technique which couples electrokinetics with adsorption, using locally produced granular activated carbon from date palm pits in the treatment zones that are installed directly to bracket the contaminated soils at bench-scale, is investigated. Natural saline-sodic clay soil, spiked with contaminant mixture (kerosene, phenol, Cr, Cd, Cu, Zn, Pb, and Hg), was used in this study to investigate the effects of voltage gradient, initial contaminant concentration, and polarity reversal rate on the soil electrical conductivity. Box-Behnken Design (BBD) was used for the experimental design and response surface methodology (RSM) was employed to model, optimize, and interpret the results obtained using Design-Expert version 8 platform. The total number of experiments conducted was 15 with voltage gradient, polarity reversal rate, and initial contaminant concentration as variables. The main target response discussed in this paper is the soil electrical conductivity due to its importance in electrokinetic remediation process. Responses obtained were fitted to quadratic models whoseR2ranges from 84.66% to 99.19% with insignificant lack of fit in each case. Among the investigated factors, voltage gradient and initial contaminant concentration were found to be the most significant influential factors.

Mapping Soil pH Buffering Capacity of Selected Fields in the Coastal Plain

2004 ◽  
Vol 68 (2) ◽  
pp. 662-668 ◽  
Author(s):  
A. R. Weaver ◽  
D. E. Kissel ◽  
F. Chen ◽  
L. T. West ◽  
W. Adkins ◽  
...  
Keyword(s):  
Soil Ph ◽  
Coastal Plain ◽  
Buffering Capacity ◽  
Ph Buffering ◽  
Ph Buffering Capacity

scholarly journals Contrasting pH buffering patterns in neutral-alkaline soils along a 3600 km transect in northern China

2015 ◽  
Vol 12 (16) ◽  
pp. 13215-13240 ◽  
Author(s):  
W. Luo ◽  
P. N. Nelson ◽  
M.-H. Li ◽  
J. Cai ◽  
Y. Zhang ◽  
...  
Keyword(s):  
Soil Ph ◽  
Large Scale ◽  
Aridity Index ◽  
Clay Content ◽  
Northern China ◽  
Buffering Capacity ◽  
Carbonate Content ◽  
Alkaline Soils ◽  
Ph Buffering ◽  
Initial Ph

Abstract. Soil pH buffering capacity (pHBC) plays a crucial role in predicting acidification rates, yet its large-scale patterns and controls are poorly understood, especially for neutral-alkaline soils. Here, we evaluated the spatial patterns and drivers of pHBC along a 3600 km long transect (1900 km sub-transect with carbonate containing soils and 1700 km sub-transect with non-carbonate containing soils) across northern China. Soil pHBC was greater in the carbonate containing soils than in the non-carbonate containing soils. Acid addition decreased soil pH in the non-carbonate containing soils more markedly than in the carbonate containing soils. Within the carbonate soil sub-transect, soil pHBC was positively correlated with cation exchange capacity (CEC), carbonate content and exchangeable sodium (Na) concentration, but negatively correlated with initial pH and clay content, and not correlated with soil organic carbon (SOC) content. Within the non-carbonate sub-transect, soil pHBC was positively related to initial pH, clay content, CEC and exchangeable Na concentration, but not related to SOC content. Carbonate content was the primary determinant of pHBC in the carbonate containing soils and CEC was the main determinant of buffering capacity in the non-carbonate containing soils. Soil pHBC was positively related to aridity index and carbonate content across the carbonate containing soil sub-transect. Our results indicated that mechanisms controlling pHBC differ among neutral-alkaline soils of northern China, especially between carbonate and non-carbonate containing soils, leading to different rates, risks, and impacts of acidification. This understanding should be incorporated into the acidification risk assessment and landscape management in a changing world.

Acid buffering capacity and potential acidification of cotton soils in northern New South Wales

Soil Research ◽  
2003 ◽  
Vol 41 (5) ◽  
pp. 875 ◽  
Author(s):  
Balwant Singh ◽  
I.O.A. Odeh ◽  
A. B. McBratney
Keyword(s):  
Soil Ph ◽  
New South ◽  
New South Wales ◽  
Agricultural Practices ◽  
Buffering Capacity ◽  
N Fixation ◽  
Potential Threat ◽  
Study Region ◽  
South Wales ◽  
Acid Buffering

Soil acidity has been of major concern in Australia since European settlement. Acidification processes have been accelerated due to agricultural activities such as N fertiliser application and leguminous N-fixation in farm rotations. In this paper, we measured the acid buffering capacity (pHBC) of Vertosols, soils used predominantly for growing cotton in northern New South Wales. The pHBC values were used to calculate decrease in soil pH assuming net acid input due to agricultural practices. We combined the acidification results with geostatistics to spatially simulate the decline in soil pH of surface soils over time. The results indicate that it would take 10–417 years for soil pH to decrease by 1 unit on an assumed acid input of 5�kmol�H+/ha.year. Soil pH will drop by 1 unit within 100 years for 90% of the soils and within 15 years for 10% of the soils. This reflects the variability of the pHBC for the studied soils. In 50 years from present, most of the eastern and north-western parts of the study region may become highly acidic with soil pH declining to 5.5. There may be a potential threat to sustainable agriculture from acidification in the region, although more work needs to be done to corroborate the counter-effects of water fluxes and carbonate dissolution. Sensitivity analysis indicates that even at low levels of acid input, some areas in the study region may experience significant decline in soil pH in the surface layer.

scholarly journals Impact of Biochar and Different Nitrogen Sources on Forage Radish Production in Middle Tennessee

2019 ◽  
Vol 10 ◽  
pp. 1594-1610
Author(s):  
Todd Pirtle ◽  
Lee Rumble ◽  
Michael Klug ◽  
Forbes Walker ◽  
Song Cui ◽  
...  
Keyword(s):  
Microbial Activity ◽  
Soil Ph ◽  
Management Practices ◽  
Buffering Capacity ◽  
N Fertilizer ◽  
Human Consumption ◽  
Ph Buffering ◽  
Short Season ◽  
Middle Tennessee ◽  
Ph Buffering Capacity

Short-season forage radish (Raphanus sativus L. var. longipinnatus) has recently gained great popularity in Middle Tennessee and many parts of the world used as a high-quality vegetable crop for human consumption or a forage crop for winter grazing and cover cropping. In this study, we (i) estimated soil pH buffering capacity and microbial activity, (ii) quantified crop productivity influenced by different biochar amendment rates and N fertilizer management practices based on a factorial treatment design. Particularly, biochar was amended at rates of 0, 5, 20, and 40 Mg/ha; N fertilizer was applied at zero (N0), 122 kg/ha of urea (56 kg/ha of N; N1) and 4.8 Mg/ha of aged dairy cattle manure (56-60 kg/ha of N), providing a total of 12 treatments (four biochar rates × three fertilization practices). The combination of biochar and inorganic N fertilizer such as urea appeared to have positive impacts on the short-term biomass production, soil pH buffering capacity, and enhanced soil microbial activity for short-season forage radish production (P < 0.05). Future research is warranted to evaluate the use of biochar in field-based forage/vegetable studies in Tennessee.

Effects of pasture improvement with superphosphate on soil pH, nitrogen and carbon in a summer rainfall environment

1991 ◽  
Vol 31 (2) ◽  
pp. 221 ◽  
Author(s):  
GJ Crocker ◽  
ICR Holford
Keyword(s):  
Organic Carbon ◽  
Predominantly White ◽  
Soil Ph ◽  
Soil Nitrogen ◽  
New South ◽  
New South Wales ◽  
Summer Rainfall ◽  
Buffering Capacity ◽  
Fixed Nitrogen ◽  
South Wales

The effects of pasture improvement on soil pH, total nitrogen, organic carbon and extractable phosphorus (P) were determined by analysing adjacent soils from improved and unimproved pastures at 67 sites on the Northern Tablelands of New South Wales. Pasture improved sites contained at least 1 clover species, predominantly white clover, and had received at least 125 kg P/ha over periods of 15-45 years. The majority of pasture improved sites contained more soil nitrogen, carbon and phosphorus and were of lower soil pH than adjacent unimproved sites. However, the decreases in pH were not statistically significant and not usually related to the magnitude of the increases in other soil fertility parameters nor to the amounts of superphosphate applied or duration of fertiliser history. The largest decline in soil pH and largest increase in organic carbon were on granitic soils which had received more than 250 kg P/ha. The relatively small decreases in soil pH and lack of relationship with fertiliser history, compared with soils from southern New South Wales, were attributed to: (i) re-cycling of legume-fixed nitrogen by summer-growing grasses; (ii) the naturally lower pH, higher nitrogen content and higher buffering capacity of many northern soils. Soil acidification therefore seems to be much slower and less frequent in the perennial pasture systems of the Northern Tablelands of New South Wales.

Carbonate chemistry, pH, and physical properties of an alkaline sodic soil as affected by various amendments

Soil Research ◽  
1997 ◽  
Vol 35 (1) ◽  
pp. 149 ◽  
Author(s):  
M. Chorom ◽  
P. Rengasamy
Keyword(s):  
Soil Solution ◽  
Soil Ph ◽  
Green Manure ◽  
Interactive Effect ◽  
Aggregate Stability ◽  
Co2 Production ◽  
Carbonate Chemistry ◽  
Sodic Soil ◽  
Mechanical Dispersion ◽  
Effects Of Ph

A greenhouse experiment evaluated the chemical and physical changes of a Natrixeralf (with alkaline pH 9·4 and 5% CaCO3), as influenced by the changes in carbonate chemistry, pH, and particle charge following the application of gypsum, green manure, and glucose. Gypsum reduced the pH from 9·38 to 7·89, increased Ca2+ in soil solution, and decreased the sodium adsorption ratio (SAR1:5) from 11·6 to 1·2. Green manure, due to increased CO2 production, reduced the pH to 8·68 and SAR1:5 to 7·52. Green manure plus gypsum reduced pH to 7·67 and SAR1:5 to 0·91. The interactive effect of gypsum and green manure on all soil properties was highly significant as shown by ANOVA analysis. Reduction of soil pH was also reflected in the levels of carbonates in the soil solution. Addition of glucose increased the microbial activity and produced fatty acids. The drastic reduction in pH (<6·0) was related to the amount of glucose added. The concentrations of Ca 2+ and carbonates, and SAR1:5 values, were inversely related to the soil pH after glucose addition. The data on soluble Na2CO3 and NaHCO3, zeta potential, mechanical dispersion, aggregate stability, and saturated hydraulic conductivity confirm the effects of pH reduction and carbonate solubility as influenced by the amendments in alkaline sodic soil.

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