• Proceedings of the KSEEG Conference
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• 2007.04a
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• pp.28-30
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• 2007

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.904-909
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• 2012

Acid sulfate soil (ASS) and potential acid sulfate soil (PASS) are distribution in worldwide and originate from sedimentary process, volcanic activity, or metamorphism and are problematic in agriculture and environmental due to their present and potential acidity developed by the oxidation. The PASS was defined as soil materials that had sulfidic layer more than 20 cm thick within 4 m of the soil profile and contained more than 0.15% of total-sulfur (T-S). A tentative interpretative soil classification system was proposed weak potential acid sulfate (T-S, 0.15-0.5%), moderate potential acid sulfate (T-S, 0.5-0.75%) and strong potential acid sulfate (T-S, more than 0.75%). PASS due to excess of pyrite over soil neutralizing capacity are formed. It provides no information on the kinetic rates of acid generation or neutralization; therefore, the test procedures used in acid base account (ABA) are referred to as static procedures. The net acid generation (NAG) test is a direct method to measure the ability of the sample to produce acid through sulfide oxidation and also provides and indication. The NAG test can evaluated easily whether the soils is PASS. The samples are mixed sandy loam and the PAS from the hydrothermal altered andesite (1:3, 1:8, 1:16, 1:20, 1:40, 1:80 and 1:200 ratios) in this study. We could find out that the NAG pH of the soil containing 0.75% of T-S was 2.5, and that of the soil has 0.15% of T-S was 3.8. NAG pH test can be proposed as soil classification criteria for the potential acid sulfate soils. The strong type has NAG pH of 2.5, the moderate one has NAG pH of 3.0, and the weak one has NAG pH of 3.5.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.5
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• pp.293-302
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• 2008

The limiting factors to determine available soil depth were studied with 390 soil series in soil profile description and physicochemical data in Korean soils. The limiting factors were coarse sandy layer, gravel and skeletal layer, hardpan layer, cat clay layer, poorly drained layer, salt accumulated layer and bed rock layer so on. The soils of having limiting factors were 332 soil series, but soils without limiting factors were 58 soil series. Soils with limiting factors were, hardpan 5, slopeness 93, immature soil 29, cinder 5, sandy 42, gravel or skeletal 47, bedrock 19, high salt content 8, poorly drained soil 22, heavy clay 32, sulfate soil 3 and ash soil 27 etc. And the orders of available soil depth were immature > slopeness > ash > heavy clay > sandy > gravel or skeletal > hardpan > cindery > poorly drained > bedrock > acid sulfate soil > salt accumulated soil etc.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.5
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• pp.311-317
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• 2000

Acid sulfate soil and potential acid sulfate soil material are worldwide in distribution and are problematic in agriculture and environment due to their present and potential acidity developed by the oxidation of sulfides. Most of them are sedimentary origin and a few cases are reported as volcanic or metamorphic origin. We report a potential acid sulfate soil material originated from volcanic activity during Mesozoic. A profile of Bongsan series-weathered nonpyritic andesite-hydrothermally altered pyrite rich andesite was studied with field examination, chemistry, and mineralogy. Once, the pyrite rich andesite was exposed to atmosphere by excavation and leveling works for a residential area and the lay out site had subsequent acidification problem of soil and surface water. The parent material and soil profile of Bongsan series had no signs of presence of pyrite and acid sulfate weathering such as yellow mottles. However, the hydrothermally altered andesite substrata contained significant amount of pyrite showing characteristics of hydrothermal origin such as cubic and pyritohedron morphology and occurrence along cracks.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.4
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• pp.171-176
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• 1975

The rate and extent of decomposition of rice straw and compost in an acid sulfate soil amended with urea and lime and incubated under aerobic and anaerobic(flooded) conditions were investigated in the laboratory. Results are summarized as follows: 1. The rate of compost(alone) decomposition in a flooded soil was more than twice as high as all other treatments, which included rice straw+urea, rice straw+lime, rice straw (alone), and compost+lime. Lime appeared to suppress the decomposition of compost in a flooded soil but actually enhanced its decomposition under aerobic conditions. 2. Compost decomposition in both anaerobic and aerobic environments was characterized by single maximum peak rates of $CO_2$ evolution that were reached soon after the start of incubation. 3. Both urea and lime greatly increased the rate and extent of rice straw decomposition in the soil when incubated aerobically, although urea had a greater effect than did liming. Decomposition rates were characterized by the appearance of two maximum peak rates, a greater primary peak and a smaller secondary peak. 4. The percent decomposition of rice straw in soil incubated aerobically was approximately half (10.8%) that of compost(23.1%). However, percent decomposition of these substrates in soil amended with lime was essentially the same; i.e., rice straw+lime (29.4%) and compost+lime(31.6%). 5. There is a need to investigate the possible interaction between the addition of lime (pH) and supplemental nitrogen applied to acid sulfate soils and how this interaction might affect the decomposition of organic wastes and residues.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.173-179
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• 1989

Characterization and classification of the potential acid sulfate soils found on flood-plains in Yeongnam area were summarized as follows: 1. The "Potential acid sulfate soil" layer(s) were appeared in the around 2-4m substrata of soil profiles and characterized by the fine texture, high reduction and physical unripened soft mud deposits or having higher contents of organic matter with dark color. 2. The contents of total sulfur (T-S) in those soils were ranged around 0.45-0.9% and the materials exhibited a strong acidity upon the oxidation with $H_2O_2$. Although the T-S contents was low as much as 0.15%, the sulfidic materials were also acidified strongly by the oxidation with $H_2O_2$ in the condition of lower content of carbonates. As defined in Soil Taxonomy of USDA, most of the sulfidic materials contained less than 3 times carbonate ($CaCO_3$ equivalent wt. %), but there were some which abundant in shell fragments, contained more than 3 times carbonate by weight percentage and that not much acidified by the oxidation with $H_2O_2$. 3. The contents of T-S correlated negatively with the pH oxidized by $H_2O_2$ and with the fizzing time (minutes) due to addition of $H_2O_2$. 4. The potential acid sulfate soils could be defined as soil materials that had sulfidic layer(s) more than 20cm thick within 4m of the soil profile and contained more than 0.15% of T-S with less than 3 times carbonate ($CaCO_3$ equiv. %). A tentative interpretative soil classification system was proposed, i.e., "Weak potential acid sulfate (T-S, 0.15-0.5%)", "Moderate potential acid sulfate (T-S, 0.5-0.75%)", and "Strong potential acid sulfate (T-S, more than 0.75%)". Finally, it was proposed that the "Detailed soil survey with high intensity" should be carried out in the areas of agricultural engineering works such as arableland readjustment works, in advance.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.195-201
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• 1992

A Potential acid sulfate soil derived from continental Holocene deposits on the fan-base was found and it was characterized with improvement practices. Artesian wells were scattered in the area, and the imperfectly drained soils were featured by having fine loamy with 7~30% of gravels. The potential acid sulfate soil layers were typified by having darkness in color with around 3.3~3.8% of O.M. and 0.34~0.41% of total sulfur. Soil pH ranged from 3.4 to 3.8 but it was decreased to 1.9~2.5 after oxidation with $H_2O_2$. Ground water sprang out from an artesian well contained a high amount of minerals such as Na, Ca, Mg, K, etc. and about 80ppm of sulfate which seemed to be responsible for pyrite formation. The soil was classified to member of "Fine loamy, mixed, acid, mesic, sulfic Haplaquepts" in taxonomically, and "weak potential acid sulfate soils" in interpretatively. The installation of tile drains with adding fine earth and liming were effective. However, the pH goes down to 4.8 again after 3 years of improvement practices.

• Korean Journal of Soil Science and Fertilizer
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• v.3 no.1
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• pp.23-28
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• 1970

The effect of wollastonite and manganese dioxide on the growth of rice on an acid sulfate soil were investigated in pot experiment. 1. Since aluminum content in the leachate of soil was reduced with increasing the pH and these chemical changes in the leachate were more pronounced by applying wollastonite, aluminum toxicity in flooded paddy rice was overcome by applying wollastonite, or flooding. 2. Poor growth of rice with iron toxicity-like symptoms on the untreated acid sulfate soil may be caused by excess iron and sulfur. Plants applied wollastonite, however, grew normally and did not show any symptoms. Iron and sulfur contents in the plant was reduced by applying wollastonite. 3. Because of the iron content in the both leachate and plant can be lowered by applying wollastonite, iron-toxicity was averted by applying the wollastonite. 4. Application of manganese dioxide in combination with wollastonite did not counteracted iron content in the plant as compared with the wollastonite treatment. 5. The application of wollastonite increased the dry weight of straw and grain yield. Manganese dioxide with wollastonite caused the increase of number of spickelets per panicles and ripened grains as compared with wollastonite. 6. From these results it can be concluded that the major cause of the poor growth of rice on acid sulfate soil is iron toxicity and the Fe-toxicity can be reduced by application of wollastonite.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.3
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• pp.282-288
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• 1985

This experiment was conducted to investigate the changing patterns of the available elements by the control of lime addition amount and temperature in Acid Sulfate Soils under the submerged condition. The results obtained were summarized as follows: 1. pH and contents of available phosphate, soluble silicate, $NH_4-N$, and exchangeable iron in soils were decreased but exchangeable aluminium and manganese, and water soluble sulfur in soils increased after submergence. 2. Lime treatment increased pH, available phosphate, soluble silicate, $NH_4-N$, and water soluble sulfur, but that decreased exchangeable aluminium, iron, and manganese in soils. 3. Treatment with 12me/100gr of Ca as $CaCO_3$, showed the marked effect in increasing the exchangeable aluminium and iron, and increasing pH value to about 6.5 as well as available phosphate and $NH_4-N$. 4. Increases in available phosphate, $NH_4-N$, and exchangeable iron with aging of the soil flooded and lime treated were higher at $35^{\circ}C$ than those at $25^{\circ}C$. 5. Throughout submerged period a significant positive correlation was observed between pH and soluble silicate while the pH has negative correlation with exchangeable elements such as aluminium, iron, and manganese etc.

• Korean Journal of Soil Science and Fertilizer
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• v.4 no.2
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• pp.167-175
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• 1971

A pot experiment with an acid sulfate soil from Kimhae was carried out to find out the cause of toxicity in rice plant. The effect of liming on changes in pH, Eh, Al, and $Fe^{2+}$ in soil and leachate was examined at two-week interval during the growth of rice. Also, total $P_2O_5$, $SiO_2$, Fe and Al contents in plants at harvesting stage were determined. In the early stage, the rice plant in the check soil showed the same healthy growth as did in limed soil even at high Al in soil and leachate. Around panicle forming stage, reddish brown mottlings suddenly infested all over the plants when accompanied with strong reduction, and afterward growth was severely retarded, and finally caused the significant difference in yield. During the strong reduction, significant amount of sulfide was formed only in check soils, but no free $H_2S$ was detected. Appreciable Al was still present in soil and leachate, and $Fe^{2+}$ in check soil was lower than that in limed soil, but $Fe^{2+}$ in leachate was slightly higher. Limed soils were more reduced and produced more $Fe^{2+}$ due to increased microorganism activity in the neutral pH. In the leachate, the check showed slightly higher $Fe^{2+}$ concentration but considerably higher than limed one at later stage. Appreciable amount of Al was detected only in check soil and leachate from transplanting to panicle formation stage. Plant tissues at harvesting stage contained very low P regardless of liming. Uptake of Si was markedly increased by liming. Contents of Fe an Al was markedly higher in check than limed one, but difference in Fe content was more drastic possibly due to more Fe uptake in presence of markedly higher $Fe^{2+}$ in soil and leachate at later growing stage. In conclusion toxic symptom in this acid sulfate soil seems to be primarily due to Al when accompanied with low pH and strong reduction. But association with $Fe^{2+}$ toxicity is not completely excluded. In order to differentiate the effect of $Fe^{2+}$ from that of Al more detailed plant analysis at different stage is required.