• Korean Journal of Soil Science and Fertilizer
• /
• v.21 no.3
• /
• pp.301-306
• /
• 1988

Contents and distribution of amino acids in the hydrolysates of humic acids extracted from straw of rice and barley at three different dates during decomposition were examined. The results obtained from this study may be summed up as the following: 1. There are differences between the humic acid hydrolysates from rice straw and barley straw in regards of composition of humic acids and distribution of amino acids. 2. Neutral amino acids as a group occupy the largest share, followed by acidic amino acids and basic amino acids. 3. The total amount of amino acids per gram of humic acid is greater in straw of rice than in straw of barley. 4. With the humification progressing the content of lysine increases, but the content of histidine decreases. In general glycine, glutamic acid, aspartic acid, alanine and leucine constitute the 5 predominant amino acids in all hydrolysates. 5. Arginine is not detected at all in any of the hydrolysates of humic acids obtained from humified materials. 6. The presence of phenylalanine and tyrosine is an evidence for the aromatic characteristics of humic acids.

• Korean Journal of Soil Science and Fertilizer
• /
• v.40 no.1
• /
• pp.71-76
• /
• 2007

We investigated the effects of solution pH on swelling characteristics and relevant hydraulic conductivity of different particle sizes of Na-bentonite which have significantly high swelling capacity. The results showed that the time taken to reach the maximum swelling indexes for all pH levels ranged from 84 hours and 156 hours for pH 6.5 or above by NaOH and pH 3.5 by HCl, respectively. The maximum swelling index slightly increased with increasing particle size, while the maximum swelling indexes were less or approximately half of that of the indigenous Na-bentonite. The changes in swelling indexes before and after solution treatment were distinctive in acidic condition, especially in pH 3.5 by HCl while there were not much differences in alkali condition. For hydraulic conductivities of fully swelled Na-bentonite in a given solution pH, elution did not occur under pressure below 1 bar. But elution started as the pressure was raised to 1.5 bars or above after 500 seconds. The stabilized hydraulic conductivities observed from 1.5, 3.0, and 5.0 bars ranged from $7{\times}10^{-3}cm\;day^{-1}$ to $6{\times}10^{-3}cm\;day^{-1}$, indicating that the hydraulic conductivities were slightly higher in acidic condition than that of normal condition.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.7 no.1
• /
• pp.64-73
• /
• 2005

This study was done to determine the regional adaptability of Dioscorea opposita in Korea. Suwon, Chunchon, Kangneung, Yonchon and Taean had soil pH of 6.62, 5.65, 5.9, 5.9 and 5.82, respectively, being at more unfavorable conditions than a standard soil condition for yam with pH 6.2. The amounts of organic matter in Suwon, Chunchon, Taean, and Yonchon were 1.96%, 4.51%, 3.76%, 1.89% and 1.12%, respectively, being at more favorable conditions than a standard organic matter in soil for yam with 2.0~3.0%. As the results from cultivating of large plantings in different regions, Suwon showed the largest the tuber dry weight of 135g. In comparison of general component between round yam and short yam in the area of Kangneung, protein of round yam(3.30%) was higher than that of short yam(1.40%). Dryness in round yam(36.5%) was lower than that of short yam(28.9%), indicating a higher dry weight ratio of round yam. In tuber extracts analysis, saponins content was respectively 23.7mg/g in round yam and 10.4mg/g in short yam.

• Applied Biological Chemistry
• /
• v.17 no.3
• /
• pp.193-218
• /
• 1974

These studies were carried out for the elucidation of liming effect on the growth of rice seedlings and the chemical characteristics of an acid sulphate paddy that shows not only extremely high acidity of soil but also poor growth of rice plants, consequently low yield. Thus the liming effect on the changes of acidity, oxidation-reduction potential, and the contents of iron, aluminium, sulphate, and phosphorus fractions in the soil was investigated under the waterlogging and drying condition. The reclaimable or inhibitory effect of phosphorus, iron and aluminium on the growth of rice seedlings was also investigated under liming. The results are summarized as follows: 1. After liming, the pH of the acid sulphate subsoil decreased again on drying. 2. The oxidation-reduction potential reached a minimum after 5 days of flooding and greatly decreased on liming but increased after drying. 3. The contents of ferrous iron soluble in water-and Morgan's solution reached a maximum after 15 days of flooding and only the content of water soluble ferrous iron was greatly decreased. 4. The content of aluminium soluble in water-and Morgan's solution decreased by flooding and liming, and showed a tendency to increase on drying. 5. In the limed acid sulphate soil, the content of water soluble calcium showed a highly significant negative correlation with the content of sulphate and liming decreased sulphate content in the soil. 6. The contents of total phosphorus was 496.3 ppm in the acid sulphate topsoil and 387.5 ppm in the subsoil. The content of each phosphorus fraction was in the order of Fe-P>Occ. Fe-P>Ca-P>Occ. Al-P>Al-P and Fe-P content in the soil was the highest fraction among them. 7. Lime application increased greatly Ca-P and Al-P, and Occ. Fe-P and Occ. Al-P only slightly, but decreased Fe-P differently in each soil. 8. Effect of phosphorus on the dry matter yield of rice seedlings was great. The optimum amount of phosphorus to produce maximum dry matter yield of rice seedlings appeared to be 6.8% of maximum absorption (absorption coefficient) without liming and 10.0% with liming. 9. In rice seedlings liming increased the content and uptake of calcium and silica but decreased those of iron and aluminium. Phosphorus application increased the content and uptake of phosphorus and decreased iron while the application of iron and aluminium increased their contents and uptake but decreased those of phosphorus. 10. Liming greatly alleviated such toxicity of iron and aluminium. 11. When phosphorus was applied, the dry matter yield of rice seedlings showed highly significant positive correlations with uptake of phosphorus, calcium and silica each. When iron and aluminium were applied, dry matter yields indicated significant positive correlations with the contents or uptake of calcium and silica each, but significant negative correlations with the content or uptake of iron and aluminium. 12. Under the application of phosphorus and lime, dry matter yields showed significant positive correlations with pH and Morgan's extractable calcium each of the soil samples after harvest. Under the application of lime, iron and aluminium, dry matter yields showed significant positive correlations with pH, calcium and silica each, but negative correlations with iron and aluminium contents each of the soil samples after harvest.

• Journal of Korean Society of Forest Science
• /
• v.81 no.1
• /
• pp.30-39
• /
• 1992

Artificial acid rain(pH2.0, 3.0, 4.0 and 5.0) was treated on the seeded pots of 4 species to examine its effects on germination, leaf injury and seedling growth. Aluminum ammonium sulfate solution (0.5, 1.0 and 2.5mM) and artificial acid rain (pH3.0, 4.0 and 5.0) were treated on the seeded germinators of 3 species to examine its effects on germination and radicle growth. Artificial acid rain was prepared by diluting sulfuric acid with ground water and ground water(pH6.5) was used as control. Artificial acid rain was sprayed to seeded pots three times per week. About 5mm of artificial acid rain was treated each time from early April to early October, 1991. Germination, seedling establishment, radicle growth, leaf injury and seedling growth were measured and compared among the treatments. The results were summarized as follows 1. Germination, seedling establishment rate of Pinus densiflora were highest on the pH5.0 pot whereas those of Ailanthus altissima was highest on the control pot, and those of Magnolia sieboldii showed the highest value on the pH3.0 pot. 2. The differences in seedling height of Pinus densiflora and Pinus rigida were significant among the treatment levels of acid rain, whereas those of Magnolia sieboldii and Ailanthus altissima were not significant. Seedling heights of Pinus densiflora and Pinus rigida were highest on the pH3.0 pot, and that of Magnolia sieboldii was highest on the pH4.0 pot, and that of Ailanthus altissima was highest on the control pot. 3. Seedling dry weights of Pinus densiflora. Pinus rigida, and Ailanthus altissima differed significantly among the treatments, but that of Magnolia sieboldii did not differ. Highest seedling dry weights of Magnolia sieboldii and Ailanthus altissima were observed on the pH4.0 pot, and that of Pinus densiflora was observed on the pH3.0 pot, and that of Pinus rigida was observed on the pH5.0 pot. 4. With decrease of pH value of artificial acid rain, the number of injured needle and injured individual tended to be increased. 5. The differences in effects of soil acidity were highly significant among the treatments for all species. 6. Radicle growth of Pinus densiflora differed significantly among pH levels and aluminum concentrations.

• Journal of Korean Society of Forest Science
• /
• v.83 no.4
• /
• pp.460-472
• /
• 1994

This study has been conducted to give some ideas for reasonable ecological management of Taejon city and its adjacent forest ecosystem against the effect of acid rain. Rain monitoring points to analyse its components represented 1 point in industrial area, 4 points in commercial area, 4 points in residential area, and 5 points in suburban area and forest survey was done in 7 forest sites adjacent to rain monitoring points. Transformed vegetation index(TVI) based on Landsat TM data was analysed for forest area. Taejon area was seriously contaminated by air pollutants and average concentration of anions in precipitation were 20.16mg/l for $SO_4{^{2-}}$, 3.65mg/l for $NO_3{^-}$, and 3.09mg/l for $Cl^-$. Anion in precipitation were $1.09mg/m^2/month$ for $SO_4{^{2-}}$, $0.23mg/m^2/month$ for $NO_3{^-}$, and $0.20mg/m^2/month$ for $Cl^-$. Cation in precipitation were $0.14mg/m^2/month$ for $Ca^{2+}$, $0.10mg/m^2/month$ for $NH_4{^+}$, $0.08mg/m^2/month$ for $Na^+$, $0.07mg/m^2/month$ for $K^+$, and $0.08mg/m^2/month$ for $Mg^{2+}$. The region with the highest concentration of $SO_4{^{2-}}$, $NO_3{^-}$, and $Cl^-$ in rain was industrial area. $SO_4{^{2-}}$, $NO_3{^-}$, and $Cl^-$ concentrations in industrial area were 43.08, 3.88, and 3.64ppm, respectively. Forest soil showed strongly acidic ranging pH4.16-4.94. Transformed vegetation index(TVI) were 3.11 in Dangsan, 4.00 in Kyechoksan, 4.13 in Bomunsan, 4.18 in Kabhasan, 3.34 in Bongsan, 4.13 in Sikchangsan, and 4.20 in Seongchisan. Dangsan forest located near in industrial area showed the lowest TVI.

• Economic and Environmental Geology
• /
• v.41 no.6
• /
• pp.695-708
• /
• 2008

In order to evaluate the geochemical behaviors of elements with waste rocks in the abandoned Jangpoong Cu mine area, total concentration analysis and leaching experiments were performed. The content of elements within waste rocks compared with background values decreased in order of As>>Cu>Pb>Cd>Co. Leaching experiments were carried out at various extraction environments, considering the acid rain ($0.00001{\sim}0.001N\;HNO_3$) and the acid mine drainage ($0.001{\sim}0.1N$ HNO3). After 24 hours of reaction with different acidic solution, the leaching characteristics of waste rocks were classified into three types according to final pH of leaching solution. Type I refers to the case that the final pH of leaching solution was lower than that of the reaction solution due to the dissolution of acidic minerals from rocks, while type 2 and 3 refer to the case that the final pH maintained higher than that of the reaction solution. Theses types include in acid buffering minerals such as clay minerals and carbonate minerals. The leaching characteristics of the elements after the reaction could be categorized into As-Co-Fe, Cu-Mn-Cd-Zn, and Pb. As-Co-Fe started to get leached under 2.5 of pH regardless of changes in the final pH, and Cu-Mn-Cd-Zn showed different initial leaching pH according to the types of final pH changes. Based on the pH value where leaching started regardless of leaching concentration, the relative mobility of each element was in the order of Mn Zn>Cd>Cu>>Fe Co>As>Pb. Thus, more higher mobility elements(Zn, Mn and Cu) were leached by reacting with acid rain water. Acid mine drainage may result in distributions of elements having relatively less mobility(As, Fe, Co and Pb).

• Korean Journal of Soil Science and Fertilizer
• /
• v.7 no.1
• /
• pp.23-27
• /
• 1974

A pot experiment was carried out to investigate the effect of phosphate application and the adjustment of base saturation rate of soils on the growth of soybean. The soils used were very low in available phosphate (10-20ppm) and low in base saturation rates (less than 40%). Treatment included 2 levels of $P_2O_5$ $(40-80ppm){\times}3$ levels of base saturation rates (check, 60.80%) In adjusting the base saturation rate, the ratio between Ca and Mg was maintained at 65:15. Results are summarised as folloing. (1) The levels of phosphate in the experiment did not bring forth significant difference in the yield of soybean. Both 40 and 80ppm of $P_2O_5$ were seemed to be not enough to bring up the remarkable phosphate effect. (2) The increase in base saturation rate of the soils up to 60% proved to be significant in increasing the yield of soybean. Above that level, however, did not affect the yield. (3) The major factor for the increase of yield, in base saturation rate adjustments was the increased Mg-saturation rates. In the range of 10-15% of Mg-saturation rate of soils, there was a linear positive relationship between the yield of soybean and Mg-saturation rate of soils, while the optimum levels of Ca-saturation rates of soil were found to be 35-55%. (4) It was pointed that there is some possibility of relative in-sufficiency of Mg in Korean cultivated soils and that the continued application of liming materials which do not contain proper amounts of Mg may aggravate these situation.

• Economic and Environmental Geology
• /
• v.47 no.2
• /
• pp.87-96
• /
• 2014

The objectives of this study were to characterize the physicochemical properties and mineralogy of Hwangto (yellow residual soils) from the southwestern part of Korea and to understand the soil-forming processes of the residual soils from their parent rocks. Both the yellowish residual soils as well as the unweathered and weathered parent rocks were obtained from Jangdong-ri, Donggang-myun, Naju, Jeollanam-do, Korea. The soil samples were examined to analyze the said soil's physicochemical properties such as color, pH, and particle size distribution. A scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis were performed in order to understand the mineralogy, chemical composition, and morphology of the soils. Two thin sections of a parent rock were analyzed to study its mineral composition. A particle size analysis of the soils indicates that the residual soil consists of mainly silt and clay (approximately 95%) and that soil textures are silty clay or silt clay loam. The soil colors of the residual soil are dark brown (7.5YR 3/4) through yellowish red (5YR 4/6). The pH of the residual soil ranges from 4.3 to 5.1. The major minerals of the parent rocks were quartz, biotite, chlorite, and plagioclase. The mineralogy of the sand fraction of the residual soil was quartz, biotite, muscovite and sanidine. The mineralogy of the silt fraction of the residual soil was quartz, biotite, muscovite, Na-feldspar, K-feldspar, and sanidine. The clay mineralogy of the soil was goethite, kaolinite, ilite, hydroxy-interlayed vermiculite(HIV), vermiculite, mica, K-feldspar and quartz. The mineral composition of the residual soil and the parent rock indicates that feldspar and mica in the parent rock weathered into illite, vermiculite and hydroxy-interlayed vermiculite(HIV), and finally changed into kaolinite and halloysite in the yellowish residual soils.

• Korean Journal of Environmental Biology
• /
• v.30 no.2
• /
• pp.90-97
• /
• 2012

Environmental characteristics and vegetation of the natural habitats of Eranthis byunsanensis B.Y. Sun were investigated in order to provide the basic data for conservation, restoration, and utilization of this Korean endemic plant. This study was conducted in Anyang, Byeonsan, Geoje, Gyeongju, Jeju, Ulsan and Yeosu. E. byunsanensis was distributed around the altitudes of 84~585 m with a slope degree of $10{\sim}20^{\circ}$, and mostly formed discontinuous populations in north-east part of valleys. Soil analysis showed the mean organic matter of 9.6% and a slightly acidic pH (mean pH of 4.9). The mean gravimetric water content was 16.5%. Correlation coefficients between environmental factors and community characteristics suggested that there was a positive correlation between slope degree and soil water content, between slope degree and soil pH, between soil organic matter and importance value, and between species richness or evenness and species diversity. The vascular plants from 59 quadrats of 7 habitats were identified into 144 taxa. A few species were dominants and similarly distributed in Byeonsan, Jeju, Ulsan and Yeosu. The highest species diversity was found in Geoje (1.43), while Anyang showed the lowest (0.87). Species evenness of Gyeongju and Jeju was bigger than 0.8, but that of Geoje was the lowest (0.59). Dominant species of woody plants in and around the 59 plots were represented by high frequency of Acer pictum subsp. mono, Carpinus cordata, Lindera obtusiloba, and Carpinus laxiflora. The results of this study can provide useful data for conservation and restoration of natural habitats of Korean endemic Eranthis byunsanensis and for the development and growth of this species for ornamental purposes.