• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.1049-1056
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• 2020

Ultrafine dust causes asthma and respiratory and cardiovascular diseases when inhaled. Ammonia (NH3) plays a big role in ultrafine dust formation in the atmosphere by reacting with nitrogen oxides (NOx) and sulfur oxides (SOx) emitted from various sources. The agricultural sector is the single largest contributor of NH3, with the vast majority of emissions ensuing from fertilizers and livestock sector. Interest in using biochar to attenuate these NH3 emissions has grown. This experiment was conducted to study the effects of using rice hull biochar pyrolyzed at three different temperatures of 250℃ (BP 4.6, biochar pH 4.6), 350℃ (BP 6.8), and 450℃ (BP 10.3) on the emission of ammonia from soil fertilized with urea. The emissions of NH3 initially increased as the experiment progressed but decreased after peaking at the 84th hour. The amount of emitted NH3 was lower in soil with biochar amendments than in that without biochar. Emissions amongst biochar-amended soils were lowest for the BP 6.8 treatment, followed in an ascending order by BP 10.3 and BP 4.6. Since BP 6.8 biochar with neutral pH resulted in the lowest amount of NH3 emitted, it can be concluded that biochar's pH has an effect on the emissions of NH3. The results of this study, therefore, indicate that biochar can abate NH3 emissions and that a neutral pH biochar is more effective at reducing gaseous emissions than either alkaline or acidic biochar.

• Korean Journal of Environmental Agriculture
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• v.27 no.2
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• pp.133-138
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• 2008

Fire can affect microbial community structure of soil through altered environmental conditions, nutrient availability, and biotic source for microbial re-colonization. We examined the influence of fire on chemical properties and soil enzyme activities of soil for 10 months. We also characterized the soil microbial community structure through ester-linked fatty acid analysis(EL-FAME). For this study, we established five burned plots(1*1 m) and 5 unburned plots outside the margin of fire. Soil was sampled three soil cores in a each plots and composited for analysis at 1, 3, 5, 8, and 10 month after fire. The fire caused an increase in soil pH, exchangeable Ca, and Mg, organic matter, available $P_2O_5$ compared to unburned sites. The content of $NH_4-N$ in burned site was significantly higher than that of unburned site and this effect continued for 8 months after fire. There was no difference of $NO_3-N$ content in soil between burned and unburned site. Fire caused no change in acid phosphatase and arylsulfatase activities but $\beta$-glucosidase and alkaline phosphatase activities in burned site were increased compared to unburned site. Microbial biomass as estimated by total concentration of EL-FAMEs in burned sites was significantly higher than that of unburned sites at one month after fire. Burned site decreased the EL-FAMEs indicative of gram-positive bacteria and tended to increase the fatty acid associated with gram-negative bacteria at one and three months after fire. The sum of EL-FAME compound $18:2{\omega}6,9c$ and $18:1{\omega}9c$ as served fungal biomarkers was decreased in burned site compared to unburned site.

• Journal of the Korean GEO-environmental Society
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• v.12 no.5
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• pp.51-57
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• 2011

Generally, ready-mixed concrete(RMC) gets hardened by time, so the remaining concrete in the drum should be cleaned. But if the RMC waste water generated from this is discharged to soil without any treatment, the strong alkaline elements and heavy metals affect water and ecosystem pollution. Although about 10 to 15% of water used for cleaning in the RMC factory is discharged to soil or river, the concrete report of this affecting soil pollution has not been sufficient. Hence, in this study it was analyzed the extraction of cleaning water from RMC factories all over the country and heavy metal and pH components remaining in soil when this is penetrated to various soils having water permeability. The specimens used for the experiment are weathering soil and soils having different particle size, and it is made to be penetrated to those for 24 hours while fixed thickness of the layer is maintained. Cleaning water is divided into that before deposition treatment(sludge water) and that after deposition treatment(upper water) to be penetrated into soil, and according to the result of penetrating sludge water to soil, Cu and Mn, Fe, and Zn were found to be remained over 23 to 90%. However, it is analyzed that in upper water having deposition treatment, Cu and Mn remain as 60% or more only in weathering soil.

• Microbiology and Biotechnology Letters
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• v.28 no.6
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• pp.329-333
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• 2000

Alkaline bacterium producing a high pro-tease activity at low temperature was isolated by using enrichment culture from soil samples and identified as Bacil-lus sp. WRD-1 Cell growth was maximal at 10 hours and the optimal initial pH and culture time of culture condition for enzyme production was pH 7 and 10 hours, respectively. Temperature range of high enzyme activity were $10~40^{\circ}C$. The optimal pH and temperature for the enzyme activity were pH9 and $30^{\circ}C$.

• Journal of Soil and Groundwater Environment
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• v.14 no.1
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• pp.36-43
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• 2009

The feasibility of electrokinetic remediation was investigated in the laboratory to treat contaminated soil with Zn, Ni and F. Electro-migration and electro-osmosis are the major removal mechanisms because fluorines desorbed from soil exist as an anionic form in soil pores, and Zn and Ni exist as a cationic form. Desorption of fluorine was enhanced under the alkaline condition, but that of Zn and Ni increased under the acidic condition. Sequential pH control was effective to control the mixed wastes from contaminated soil. 2 V/cm was applied to reactor to evaluate the effect of constant voltage gradient, after two weeks, the removal efficiency of Zn, Ni and F was 20.5%, 2.5% and 57.4%, respectively. Even though the removal of Zn and Ni was very low, the pH control enhanced transport of Zn and Ni significantly. As a result, sequential pH control is a effective method to remediate mixed waste-contaminated soil.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.4
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• pp.370-376
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• 1997

Experiments were conducted to investigate the effects of chromium application level, soil pH change, soil topping, application of some metals and application of organic matter on the absorption of chromium by radish and its growth. The results of experiments are summarized as following. Application of chromium as potassium dichromate up to 50 mg/kg did not affect the germination of radish seed. Application of chromium above this level affected the germination abversely. The dry matter yield of and absorption of chromium by radish was not affected by the application of chromium up to 100 mg/kg. Increased in soil pH decreased the uptake of chromium by radish under all range of chromium application rates. Under acidic condition (pH 5-6), the increase in the application of chromium resulted in the increase in the uptake of chromium by radish and lowering of dry matter production of radish. However, under alkaline condition (pH 7-8), increased application of chromium did not affect the uptake of chromium and the dry matter yield of radish. The application of Zn, Fe and Cu, up to 100 mg/kg did not affect not affect the uptake of chromium and dry matter yield of radish. The topping of soil with untreated soil after application of chromium up to five cm, did not affect the chromium uptake of radish, the same treatments tended to increase the dry matter yield of radish. The application of organic fertilizer(obtained from local market) up to the amount equivalent to 3000 kg/ha, although increased the dry matter yield of radish, did not affect the uptake of chromium by radish significantly. All the treatments tested in this study did not affect the translocation of chromium between root and shoot of radish.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.4
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• pp.280-284
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• 1989

The soil texture and the physico-chemical characteristics of 442,000ha reclaimable tide land in the south-western of korean peninsular were analysed. The subsidence which may occur as the soil ripened was studied. The results were as follows : 1. Among the 257,000ha of existing reclaimed tidal land 53.0% was tine silty soil and 36.0% coarse silty, 6.0% coarse loamy and 5.0% sandy soils, respectively. 2. Out of the total 442,000ha of reclaimable tidal land, 51.0% was coarse silty soil, and 20% sandy, 15.0% coarse loamy and 14.0% fine silty textural family, respectively. The coarse silty deposits were mainly distributed in the Gyeong gi and Jeonnam coast, while the coarse deposits(Coarse Loamy-sandy) exist in the Jeonbuk coastal area, but in the Chungnam areas there were various textural grades. 3. Reclaimable tidal Land in the south-western part of the peninsular was Classified into saline and alkaline soil. Electric Conductivity in saturation extract was extremely high that was 46~51 mmhos/cm, E.S.P was more than 25% and pH was ranged around 7.5~8.0 4. Reclaimed to cultivated field the subsidence reclaimable tide land to be expected when was about 18% in Soil and 21% in Sicl soils calculated down to 1.25m of the profile.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.245-253
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• 2014

BACKGROUND: Oyster shell(OS) is alkaline with pH 9.8, porous, and has high concentration of $CaCO_3$. It could be used as an alternative of lime fertilizer to immobilize cadmium(Cd) in heavy metal contaminated arable soil. Therefore, this study has been conducted to compare effects of calcium(Ca) materials [OS and $Ca(OH)_2$] on Cd extractability in contaminated soil and determined mechanisms of Cd immobilization with OS. METHODS AND RESULTS: Both Ca materials were added at the rates of 0, 0.1, 0.2, 0.4, and 0.8% (wt Ca wt-1) in Cd contaminated soil and the mixtures were incubated at $25^{\circ}C$ for 4 weeks. Both Ca materials increased pH and negative charge of soil with increasing Ca addition and decreased 1N $NH_4OAc$ extractable Cd concentration. 0.1 N HCl extractable Cd concentration markedly decreased with addition of OS. 1 N $NH_4OAc$ extractable Cd concentration was related with pH and net negative charge of soil, but not with 0.1 N HCl extractable Cd concentration. We assumed that Cd immobilization with $Ca(OH)_2$ was mainly attributed to Cd adsorption resulted from increase in pH-induced negative charge of soil. Scanning electron microscope (SEM) images and energy dispersive spectroscopy(EDS) analyses were conducted to determine mechanism of Cd immobilization with OS. There was no visible precipitation on surface of both Ca materials. However, Cd was detected in innerlayer of OS by EDS analyses but not in that of $Ca(OH)_2$. CONCLUSION: We concluded that Cd immobilization with OS was different from that with $Ca(OH)_2$. OS might adsorbed interlayer of oyster shell or have other chemical reactions.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.261-267
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• 2011

ACKGROUND: Cadmium (Cd) has long been recognized as one of most toxic elements. Application of organic amendments and phosphate fertilizers can decrease the bioavailability of heavy metals in contaminated soil. METHODS AND RESULTS: This study was conducted to evaluate effect of combined application of phosphate fertilizer and manure in reducing cadmium phytoavailability in heavy metal contaminated soil. Phosphate fertilizers [Fused and super phosphate (FSP) and $K_2HPO_4$ (DPP)] and manure (M) were applied as single application (FSP, DPP, and M) to combined application (FSP+M and DPP+M) before radish seeding. $K_2HPO_4$ decreased $NH_4OAc$ extractable Cd and plant Cd concentration, mainly due to increases in soil pH and negative charge. However, FSP increased $NH_4OAc$ extractable Cd and plant Cd concentration. Manure significantly increased soil pH and negative charge. Combined application of phosphate fertilizer and manure were much more effective in reducing Cd phytoavailability than a simple application of each component. Calculated solubility diagram indicated that Cd concentrations in the solution of soils amended with phosphate fertilizers and manure were undersaturated with respect to all potential Cd minerals [$Cd_3(PO_4)_2$, $CdCO_3$, $Cd(OH)_2$, and $CdHPO_4$]. Plant Cd concentration and $NH_4OAc$ extractable Cd were negatively related to soil pH and negative charge. CONCLUSION: Alleviation of Cd phytoavailability with phosphate fertilizer and manure can be attributed primarily to Cd immobilization due to the increase in soil pH and negative charge rather than Cd and phosphate precipitation. Therefore, combined application of alkaline phosphate materials and manure is effective for reducing Cd phytoavailability.

• Microbiology and Biotechnology Letters
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• v.28 no.6
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• pp.322-328
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• 2000

To screen agent for the treat-ment of Alzhimers Disease several strains of bacteria producing acetylcholinesterase inhibitor ware isolated from soil. Strain 960903 showed strong acetylcholinesteras inhibitory activity and low butyrylcholinesterse inhibitory activity. The strain 960903 was identified as Pseudomonas sp. Acetylcholinesterase inhibitor ws highly achieved in fermentation medium containing soluble starch 3.0%, glycerol 1.0%, pharmamedia 0.5%, KCI 0.3%, $CaCO_3$ 0.2%, MgS $O_4$..$7H_2$O 0.05%, $KH_2$$PO_4$ 0.05%(pH6.5) at $30^{\circ}C$ for 4 days. Acetylcholinesterase inhibitor was purified by Diaion WA-30($OH^{-}$) column charomatography and cellulose column chromatography. Acetylcholinesterase inhibi-tor showd the maximum wavelength at 205 nm and was soluble in water, acetic acid, ethanol, methanol and dime-thyl sulfoxide. The concentration of 50% inhibition($IC_{50}$) of inhibitor against acetylcholinesterase was 25$\mu\textrm{g}$/ml. The inhibitor was inactivated on heating ar $100^{\circ}C$ fro 15 min and more stable in acidic region than alkaline region.n.