• Korean Journal of Soil Science and Fertilizer
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• v.48 no.1
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• pp.57-63
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• 2015

Bioavailability of cadmium (Cd) and arsenic (As) can be different depending on soil pH. For this reason, main purpose of this research was to compare bioavailability of Cd and As in agricultural field under varied soil pH and different extractants. Bioavailable fraction of Cd and As in soil was extracted with $CaCl_2$, $NaNO_3$, DTPA, EDTA, and low molecular weight organic acids (LMWOAs). Soil samples and cultivated crops were collected at the range of soil pH 4.5-8.5 and correlation analysis was conducted between bioavailable fraction of Cd and As in soil and total concentration of Cd and As in crops. Results showed that concentration of Cd and As in acidic soil was ranged $0.002-0.462mg\;kg^{-1}$ and $0.041-4.903mg\;kg^{-1}$ respectively. In alkaline condition, concentration of Cd and As were ranged $0.006-0.351mg\;kg^{-1}$ and $0.039-2.807mg\;kg^{-1}$ respectively. Comparing bioavailable fraction of Cd and As in acidic and alkaline soil condition, higher concentration was measured in acidic condition. Similarly, higher average concentration of Cd and Asin crops was observed in acidic condition (0.398 and $0.751mg\;kg^{-1}$ respectively) than alkaline condition (0.248 and $0.264mg\;kg^{-1}$). Among different extractants, LMWOAs method showed higher correlation ($r^2=0.545$) for Cd in acidic condition indicating that LMWOAs method could be applied for evaluating bioavailability of Cd in acidic soil. However, no high correlation was observed for As in both acidic and alkaline condition. Overall, bioavailable fraction of Cd and As can be higher in acidic condition of soil than alkaline condition resulting higher uptake of Cd and As from soil to crops. Therefore, efficient best management practice (BMPs) for Cd and As in acidic soil should be conducted for minimizing uptake of Cd and As into crops.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.713-721
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• 2023

Soil acidification challenges global food security by adversely influences soil fertility and agricultural productivity. Carbonized agricultural residues present a sustainable and ecofriendly way to recycle agricultural waste and mitigate soil acidification. We evaluated the effects of organic amendments on lettuce growth and soil chemical properties in two soils with different pH levels. Carbonized rice husk was produced at 600℃ for 30 min and rice husk was treated at 1% (w·w^-1). Carbonized rice husk increased soil pH, electrical conductivity, total carbon content, and nitrogen content compared with untreated and rice husk treatments. Furthermore, this study found that lettuce growth positively correlated with soil pH, with increasing soil pH up to pH 6.34 resulting in improved lettuce growth parameters. Statistical correlation analysis also supported the relationship between soil pH and lettuce growth parameters. The study findings showed that the use of carbonized rice husk increased the constituent elements of lettuce, such as carbon, nitrogen, and phosphate content. The potassium content of lettuce followed a similar trend; however, was higher in acidic soil than that in non-acidic soil. Therefore, improving the pH of acidic soil is essential to enhance agricultural productivity. It is considered advantageous to use agricultural residues following pyrolysis to improve soil pH and agricultural productivity.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.789-794
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• 2016

Continuous excessive application of phosphorus (P) fertilizer and manure in plastic film house soils can lead to an accumulation of P in soils. The understanding of P sorption by soils is important for fertilizer management. In this study, 9 samples were collected for acidic and calcareous soils as non-cultivated soil and plastic film house soils as cultivated soil Phosphorus sorption data of acidic soils fit the Langmuir equations, Freundlich equations in calcareous and plastic film house soils. In calcareous and plastic film house soils, the slope of isotherm adsorption changed abruptly, which could be caused P precipitation with $CaCO_3$. The calculated Langmuir adsorption maximum ($S_{max}$) varied from 217 to 1,250, 139 to 1,429, and $714mg\;kg^{-1}$ for acidic soils, calcareous soils, and plastic film house soils with low available phosphate concentration, respectively. From this result, maximum P adsorption by the Langmuir equation could be regarded as threshold of P concentration to induce the phosphate precipitation in soil. Phosphate-sorption values estimated from one-point isotherm for acidic and calcareous soils as non-cultivated soils were comparable with the $S_{max}$ values calculated from the Langmuir isotherm.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.95-97
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• 2007

Our understanding on the plant's capability to acquire the nutrients from the soil under harsh circumstance, like unfavorably high pH, and the plant's capability to protect itself under very low soil pH, has been remarkably increased in the recent years. Having those knowledges, it seems not to be wise to abide to the traditional approach to deal the problems of acidic or alkaline soils via chemical methods like liming or using acidic materials. Instead, we may try to select the crops and varieties that can better withstand soil acidity or alkalinity. This stance will be more welcomed when the conservation of environments is high priority issue.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.10a
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• pp.3-6
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• 1999

Several chemical washing procedures were applied to Parathion and Diazinon contaminated soil. Batch and column tests were performed to determine the insecticides extraction efficiency as a function of pH. Washing efficiency of methanol is more higher than that of water and HCl when washed parathion and diazinon are. Those are completely miscible with most organic solvents. For parathion, release trend is increased as pH is increased because it is hydrolyzed easily at the condition of alkali. But diazinon shows reverse because diazinon is decomposed rapidly at the condition of acidic So, diazinon is more released than parathion is because this experiment is peformed in acidic and weak acidic conditions. Generally, parathion and diazinon are classified as having low mobility, so they can be easily controlled if the proper washing process are applied.

• Korean Journal of Environmental Agriculture
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• v.20 no.5
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• pp.352-357
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• 2001

Cadmium (Cd) has been identified as a potential contaminant in agricultural and environmental soils. Ionic condition in the soils is an important factor to influence Cd availability. In this study, the effect of sulfate or nitrate application on Cd sorption in acidic and calcareous soils was investigated. The Cd, sulfate $(SO_4)$, and nitrate $(NO_3)$ sources were solutions of $CdCl_2$, $K_2SO_4$, and $KNO_3$, respectively. The soil-solution system pH was affected by the application of sulfate or nitrate in both acidic and calcareous soil system, but there was not clear pH difference between pre- and simultaneous applications of sulfate or nitrate (PAS/PAN or SAS/SAN). Solution ionic strength (I) values were similar between the acid and calcareous soil systems after applying the Cd even though it was significantly different in the untreated control soils. However after applying the sulfate or nitrate, the I values increased and were always higher with SAS/SAN treatments. Solution Cd concentration also increased with the application of sulfate or nitrate. However, the Cd concentration in soil solution controlled by Cd sorption in the systems was different between PAS/PAN and SAS/SAN treatments only in the calcareous soil system, but not in the acidic soil system. The difference in Cd concentration between SAS/SAN and PAS/PAN in the calcareous systems may be caused by system pH, ionic strength, complexation, and predominately, competition of the $Cd^{2-}$ with the index $K^+$ ion. Potassium ion-Cd competition in the acidic soil system may be minimized because of the abundance of hydrogen ions.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.201-204
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• 2004

Immobilization is seen as a promising technology for lead remediation. In a laboratory experiment, immobilization of lead with soluble P was tested as a function of reaction time and P concentration. The P treated with an acidic solution to enhance heavy metal immobilization was worked into the soil, and within 7 days, lead was stabilized. Different molar ratios of soluble phosphates (super-phosphate and KH$_2$PO$_4$) would be considerably effective to accelerate the formation of highly insoluble minerals due to the lack of leachable Pb in the contaminated soil. Although it was demonstrated that the addition of soluble phosphates with an acidic solution significantly reduced available lead in soil up to over 95%, remaining phosphorus in soil matrix might cause a possible groundwater eutrophication in the near future.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.265-269
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• 2006

This study was to investigate the effect of acidic leachate on the landfill liner system and healing of cracks by using industrial by-products; BFS(Blast Furnace Slag) and FA(Fly Ash). From the results of pH measurement, for OPC(Ordinary Portland Cement) and DM(Dredged Mud) mixtures immersed acidic leachate, the initial pH($4.5{\sim}5.5$) was heavily increased to approximately 10 after 60 days experiment due to the production of 2 mole $OH^-$ which was occurred by hydrolysis of CaO and MgO etc.. Meanwhile, the initial pH of acidic leachate immersed DM mixtures with BFS and FA respectively was lasted for longer period as compared to the comparison. The reason was that production of low Ca C-S-H hydrates which stabilized in acidic liquid. The physical properties(compressive strength, hydraulic conductivity) of DM mixtures added BFS and FA was improved. It was concluded that the dissolution of hydrates was disturbed by high alkalinity of BFS and FA.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.614-620
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• 2016

Mine soils are usually unfavorable for plant growth due to their acidic condition and low contents of organic matter and nutrients. To investigate the effect of organic material and lime on nitrogen processes in an acidic metal mine soil, we conducted an incubation experiment with treating livestock manure compost, dolomite, and oyster shell and measured soil pH, dehydrogenase activity, and concentration of soil inorganic N ($NH_4{^+}$ and $NO_3{^-}$). Compost increased not only soil inorganic N concentration, but also soil pH from 4.4 to 4.8 and dehydrogenase activity from 2.4 to $3.9{\mu}g\;TPF\;g^{-1}day^{-1}$. Applying lime with compost significantly (P<0.05) increased soil pH (5.9-6.4) and dehydrogenase activity ($4.3-7.0{\mu}g\;TPF\;g^{-1}day^{-1}$) compared with applying only compost. Here, the variation in dehydrogenase activity was significantly (P<0.05) correlated with that in soil pH. Soil inorganic N decreased with time by 14 days after treatment (DAT) due to N immobilization, but increased with time after 14 DAT. At 28 DAT, soil inorganic N was significantly (P<0.05) higher in the lime treatments than the only compost treatment. Especially the enhanced dehydrogenase activity in the lime treatments would increase soil inorganic N due to the favored mineralization of organic matter. Although compost and lime increased soil microbial biomass and enzyme activity, ammonia oxidation still proceeded slowly. We concluded that compost and lime in acidic mine soils could increase soil microbial activity and inorganic N concentration, but considerable ammonium could remain for a relatively long time.

• Journal of Korea Soil Environment Society
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• v.3 no.2
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• pp.31-39
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• 1998

A total of 112 soil samples collected from polluted and unpolluted areas in Korea were investigated for physical properities (such as soil moisture, organic matter and soil pH) and biological properties (such as microbial numbers). The results of organic matter and soil pH showed a great variation(p=0.01) in the four areas, whereas soil moisture and organic matter were similar among three plant vegetations. There was a significant relationship(p=0.01 or 0.05) between soil pH and microbial number These results imply some variations in soil environment and may lead to unfavorable changes of plant vegetation in soil. Presumably, the above results appear to be resulted from soil acidification caused by an acidic rain.