• Korean Journal of Soil Science and Fertilizer
• /
• v.11 no.2
• /
• pp.89-95
• /
• 1979

A field experiment was conducted to investigate the effects of season of application and particle-size distribution of silicate fertilizer on rice yields of Indica type, Milyang 23 and Japonica type Jinheung. The application of silicate fertilizer at the rate of 250kg per 10a increased greatly rice yields. Rice yields were a little higher when silicate fertilizer was applied at transplanting time (Spring application) than applied in Autumn of preceding year (Autumn application) and increased with increasing content of fine particles of silicate fertilizer. However, the difference in effects between the season of application was insignificant and the silicate fertilizer of particles to pass by 100% through a 8 mesh sieve and by 60% through a 25 mesh sieve, 8-25(60%) was as effective as the one to meet silicate fertilizer specifications, 10-28(60%). Silica content of plant samples did not show any significant effects of season of application and particle-size distribution of silicate fertilizer, whereas samples taken at 50 days after tran planting showed significant effects of season of application and particle-size distribution. Silica content of straw of Jinheung was highest when 8-25(60%) was applied. Silica content of soils before the experiment was 36.7 ppm and the content increased to range of 159.5-273.8 ppm and 80.3-134.4 ppm in the plots of Spring application and Autumn application respectively.

• Korean Journal of Soil Science and Fertilizer
• /
• v.42 no.5
• /
• pp.336-340
• /
• 2009

The issue of acid precipitation and related environmental problems in East Asia has been emerging. To evaluate the acidity and chemical characteristics of rainwater in Korea, its chemical properties during cultivation season from April to October were investigated at Taean in 2007. Also, to estimate the contribution of ions on its acidity, ion composition characteristics and neutralization effects by cation ions were determined. The ion balance between cations and anions values showed high correlation. The mean values of pH and EC were 4.9 and $32.9{\mu}S\;cm^{-1}$, respectively. The EC of rainwater showed seasonal characteristic, which was $91.4{\mu}S\;cm^{-1}$ with relatively low rainfall compared with other monitoring periods. $Na^+$ was the main cation followed by $NH_4{^+}$ > $Ca^{2+}$ > $H^{+}$ > $Mg^{2+}$ > $K^+$. Among these ions, $Na^{+}$ and $NH_4{^+}$ covered over 70% of total cations. In the case of anion, the order was $SO_4{^{2-}}$ > $NO_3{^-}$ > $Cl^{-}$. The mean value of sulfate, which is main anion component in the samples was $152.1{\mu}eq\;L^{-1}$. Also, 90% of soluble sulfate in rainwater was $nss-SO_4{^{2-}}$(non-sea salt sulfate). With fractional acidity and theoretical acidity of rainwater samples, $NH_4{^+}$ and $Ca^{2+}$ contributed greatly in neutralizing the rain acidity.

• The Journal of Engineering Geology
• /
• v.28 no.4
• /
• pp.631-643
• /
• 2018

Uranium and radon concentrations in groundwater from 80 wells from Daejeon area were measured to determine the range of concentrations according to the geology. The median uranium content of groundwater was $11.14{\mu}g/L$ for the two-mica granite, $0.90{\mu}g/L$ for the biotite granite, and $0.47{\mu}g/L$ for the Ogcheon group. The median radon content of groundwates was 114.3 Bq/L for the two-mica granite, 61.6 Bq/L for the biotite granite, and 42.2 Bq/L for the Ogchon group, respectively. The uranium content of two-mica granite is 3.78 mg/ kg, which is slightly higher than that of biotite granite 3.20 mg/kg. However, the uranium content in groundwatewr of two-mica granite groundwater is much higher than that of biotite granite. This can be explained by the fact that the two-mica granite is vulnerable to weathering than biotite granite, so uranium in mineral is easily leached into groundwater. The exceeding rate of samples having uranium content above $30{\mu}g/L$ in granite area was 23.8%, which is higher than that of 6.7% in Jurassic granite in Korea. On the other hand, the exceeding rate of samples having radon content above 148 Bq/L in granite rate area was 31.0% which is similar to that of Jurassic granite area of 31.7%.

• Journal of Soil and Groundwater Environment
• /
• v.14 no.2
• /
• pp.33-44
• /
• 2009

The objective of the study was to develop a hybrid technology integrating biological and physicochemical technologies to efficiently remediate arsenic contaminated lands such as abandoned mine area. The tailing soil samples contaminated with As at a high level were obtained from Songchon abandoned mine, and the content of arsenic and heavy metals as well as physicochemical properties and mineral composition were investigated. In addition, two sets of sequential extraction methods were applied to analyze chemical speciations of arsenic and heavy metals to expect their leachability and mobility in geoenvironment. Based on these geochemical data of arsenic and heavy metal contaminants, column-type experiments on the bioleaching of arsenic were undertaken. Subsequently, experiments on the hybrid process incorporating bioleaching and electrokinetics were accomplished and its removal efficiency of arsenic was compared with that of the individual electrokinetic process. With the results, finally, the feasibilty of the hybrid technnology was evaluated. The arsenic removal efficiencies of the individual electrokinetic process (44 days) and the hybrid process incorporating bioleaching (28 days) and electrokinetics (16 dyas) were measured 57.8% and 64.5%, respectively, when both two processes were operated in an identical condition. On the contrary, the arsenic removal efficiency during the bioleaching process (28 days) appeared relatively lower (11.8%), and the result indicates that the bioleaching process enhanced the efficacy of the electrokinetic process as a result of mobilization of arsenic rather than removed arsenic by itself. In particular, the arsenic removal rate of the electrokinetics integrated with bioleaching was observed over than 2 times larger than that obtained by the electrokinetics alone. From the results of the study, if the bioleaching which is considered a relatively economic process is applied sufficiently prior to electrokinetics, the removal efficiency and rate of arsenic can be significantly improved. Consequently, the study proves the feasibility of the hybrid process integrating both technologies.

• Korean Journal of Soil Science and Fertilizer
• /
• v.39 no.4
• /
• pp.214-223
• /
• 2006

For better management of micronutrients in crop cultivation, the availability of micronutrients in the soils must be updated and evaluated as a first step. This study was conducted to investigate the distribution of micronutrients in soils of plastic film houses. Total 396 soil samples were collected from the plastic film houses of various crops in Yeongnam province (strawberry, 96; red pepper, 66; tomato, 74; oriental melon, 97; cucumber, 63). Total and available contents of B, Cu, Zn, Fe, and Mn in the soils were determined. Available B was extracted with hot water and available Cu, Zn, Fe, and Mn were extracted with 0.1 N HCl. Mean values of total contents of B, Cu, Zn, Fe, and Mn in the plastic film house soils were 25, 32, 74, 21,316, and $420mg\;kg^{-1}$, respectively. Total contents of micronutrients in the plastic film house soils were similar to those found in the open fields nearby, while they were different among the locations investigated. Mean contents extractable B, Cu, and Zn in the plastic film house soils were 2.1, 7.5, and $35mg\;kg^{-1}$, respectively. The contents of extractable B, Cu, and Zn in the plastic film house soils were higher than those found in the open fields nearby with exceptions of B in soils of strawberry and Cu in soils of red pepper and oriental melon. However, mean contents of extractable Fe and Mn in the plastic film house soils were 156 and $146mg\;kg^{-1}$, respectively, and the mean content of extractable Fe was much lower than that found in open fields nearby. The contents of extractable Zn, Fe, and Mn were higher than the sufficient levels for the crop requirements in most of the plastic film house soils investigated. Contents of extractable Cu in most soils of strawberry, tomato and cucumber cultivations were higher than the sufficient level. However, extractable Cu contents were below the sufficient level in about 30% of investigated soils of red pepper and oriental melon cultivation. Soils containing higher contents of extractable B than the sufficient level were relatively fewer in comparison to the other micronutrients.

• Korean Journal of Soil Science and Fertilizer
• /
• v.31 no.2
• /
• pp.189-196
• /
• 1998

Swage sludge cakes produced from domestic wastewater treatment plants were collected from 21 different sites throughout Korea, and chemical properties of the sludge samples were determined. Inorganic nutrient contents did not indicate great differences among swage sludges from each sites, whereas the toxic heavy metal contents differed greatly. T-N, $NH_4{^+}-N$ and $NO_3{^-}-N$ contents from 21 sites sludges ranged 2.3-6.0, 291-4284, $1.4-58.8mg\;kg^{-1}$, respectively. Heavy metal (Cd, Cu, Pb and Zn) contents ranged 2.86-58.22, 144.0-5417.3, N.D.-943.5, and $N.D.-8,083mg\;kg^{-1}$, respectively. One of the sludges was treated to soils at rates of 12.5, 25, 50. and 100, $Mg\;ha^{-1}$ and incubated for 12 weeks to determine nitrogen materialization rate. Ammoniun nitrogen content decreased sharply at higher rates of sludge treatment up to 8 weeks after treatment and did not change much, while $NO_3{^-}$ increased at all treatment levels. The net amount of mineralized N of sludge treatment rates (12.5, 25, 50, and $100Mg\;ha^{-1}$) during 12weeks incubation were 189.0, 277.2, 303.8 and $376.6mg\;kg^{-1}$.

• Journal of Soil and Groundwater Environment
• /
• v.10 no.5
• /
• pp.25-36
• /
• 2005

Several metalliferous and coal mines, including Myungjin, Seojin and Okdong located at the upper watershed of Okdong stream, were abandoned or closed since 1988 due to the mining industry promotion policy. Thus these disposed an enormous amount of mining wastes without a proper treatment facilities, resulting in water pollution in the downstream areas. Acid mine drainage (AMD) and waste water effluents from the closed coal mines were very strongly acidic showing pH ranges of 2.7 to 4.5 and had a high level of Total Dissolved Solids (TDS) showing the ranges of 1,030 to 1,947 mg/L. Also heavy metal concentrations in these samples such as Fe, Cu, Cd and anion such as sulfate were very high. Concentrations of water soluble heavy metals in the Okdong streams were in the orders of Fe>Al>Mn>Zn>Cu>Pb>Cd, indicating Fe from the AMD and waste water effluents contributed greatly to the quality of water and soil in the lower watershed of Okdong stream. Copper concentrations in the effluents from the tile drainage of mine tailings dams were highest during the raining season. Water Pollution Index (WPI) of the surface water at the upper stream of Okdong river where AMD of the abandoned coal mines was flowed into main stream were in the ranges of 16.3 to 47.1. On the other hand, those at the mid stream where effluents from tailings dams and coal mines flowed into main stream were in the WPI ranges of 10.6 to 19.5. However, those at the lower stream were ranged from 10.6 to 14.9. These results indicated that mining wastes such as AMD and effluents from the closed mines were the major source to water pollution at the Okdong stream areas.

• Journal of the Korean earth science society
• /
• v.25 no.6
• /
• pp.428-442
• /
• 2004

Dustfall samples were collected by the modified American dust jar (bulk type) at 5 sampling sites in the Nakdong river area from lune 2002 to May 2003. Nineteen chemical species (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Si, V, Zn, $Cl^-$, $NO_3^-$, $SO_4^{2-}$, and $NH_4^+$) were analyzed via the combination of ICP/AES, AAS, IC and UV. The purposes of this study were to qualitatively evaluate the chemical composition of dustfalls by examining their regional and seasonal distribution patterns. Computation of the enrichment factor showed that well-defined anthropogenic sources, particularly in Pb were found in the order Gamjeondong (industrial area), Wondong, Silla University, Samrangiin and Mulgum. The seasonal mean of soil contribution showed its highest value (16.3%) during the winter with an annual mean of 11.2%. The concentration ratio of [$SO_4^{2-}/NO_3^-$] was found to be highest (5.12) during the winter, while the lowest ratio value (3.30) was seen during the all. fall, Also regional equivalent ratios of [$SO_4^{2-}/NO_3^-$] were found in the order: Silla University (6.78), Gamjeondong (4.98), Mulgum (3.95), Wondong (3.85), and Samrangjin (2.87). Seasonal distribution of water soluble components for total dustfall were found in the order: spring (71.6%), summer (61.2%), fall (49.2%) and winter (48.6%) with a mean ratio of 57.6%. Regional contribution of sea salts of water soluble ions were found in the order: Silla university (34.5%), Gamjeondong (28.3%), Wondong (17.3%), Samrangiin (17.2%) and Mulgum (13.8%), the total mean contribution rate was 22.1%. As for the chemical composition of dustftll on the lower Nakdong river, there is a decreased influence of sea salt and artificial anthropogenic sources and increased influence of soil particle inland. Also, the total amount of deposition on the lower Nakdong river has decreased, with the river's surface serving as a confounding factor in resuspending dusts.

• Korean Journal of Environmental Agriculture
• /
• v.19 no.4
• /
• pp.319-323
• /
• 2000

This study was conducted to compare fractionations and availability of heavy metal in paddy soils near five abandoned mining areas. The sequential extraction procedure was used to fractionate the heavy metals in soils into the designated from water $soluble(H_2O)$, $exchangeable(0.5M\;KNO_3)$, organically bound(0.5M NaOH), $oxide/carbonate(0.05M\;Na_2-EDTA)$, and $sulfide/residual(4M\;HNO_3)$. EDTA and $HNO_3$ extractable of Cd, Pb, and Zn, and NaOH and $HNO_3$, extractable of Cu were predominant chemical forms. The ratio of $H_2O+KNO_3$ extractable of Cd, Zn, Cu, and Pb were 25.1, 8.7, 4.0, and 0.4%, respectively. The ratio of $H_2O+KNO_3$ extractable heavy metal were negatively correlated with soil pH, while $EDTA+HNO_3$ extractable heavy metal were positively correlated. The most consistent distribution patterns were found when the soil samples were grouped according to their total contents. Specially, the ratio of $H_2O+KNO_3$ extractable heavy metal were higher as total contents of heavy metal were increased. The ratio of $H_2O+KNO_3$ extractable heavy metal(Cd 1.06, Cu 0.15, Pb 0.01, and Zn 0.05%) were lower at the high soil pH than those(Cd 31.31, Cu 4.06, Pb 1.75, and Zn 10.16%) at the low level. Compared to other chemical forms, the degree of contribution for $KNO_3$ extractable form to the Cd uptake to brown rice was high, whereas that for EDTA and $HNO_3$ extractable forms were high to the Zn.

• Korean Journal of Soil Science and Fertilizer
• /
• v.36 no.4
• /
• pp.256-262
• /
• 2003

The emission of methane and nitrous oxide was measured from fields of upland rice and soybean. Rice cultivar, Daejinbyeo, was seeded in a row of 30 cm space in upland soil on April 28, 2001. The fields were irrigated with sprinkler irrigation or natural precipitation. Three soybean cultivars Jangyeobkong, Taekwangkong and Hwangkeumkong, were sown with seeding space of $60{\times}15cm$ on June 16, 2001. Gas samples were collected twice a week during the growth period, and methane and nitrous oxide were analyzed. Methane emission from upland rice field of sprinkler irrigation was $3.5kg\;CH_4\;ha^{-1}$. However, negative emission of methane, $-1.7kg\;CH_4\;ha^{-1}$, was observed in upland rice field of natural precipitation. Total nitrous oxide emission from upland rice field of sprinkler irrigation was $50.8kg\;N_2O\;ha^{-1}$, while the emission in the field of natural precipitation was $8.3kg\;N_2O\;ha^{-1}$. Global warming potentials (GWP) in the upland rice fields of sprinkler irrigation and natural precipitation were 15,822 and $2,216kg\;CO_2\;ha^{-1}$, respectively. Methane emissions from fields of soybean cultivars Jangyeobkong, Taekwangkong and Hwangkeumkong were -14.7, -4.3 and $4.8kg\;CH_4\;ha^{-1}$, respectively. Total nitrous oxide emissions from fields of soybean cultivars Jangyeobkong, Taekwangkong and Hwangkeumkong were 4.7, 4.6 and $3.0kg\;N_2O\;ha^{-1}$, respectively. Total GWPs for soybean cultivars Jangyeobkong, Taekwangkong and Hwangkeumkong were 1152, 1323 and $1027kg\;CO_2\;ha^{-1}$, respectively.