• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.955-960
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• 2012

In most agricultural soils, ammonium ($NH_4{^+}$) from fertilizer is quickly converted to nitrate ($NO_3{^-}$) by the process of nitrification which is crucial to the efficiency of N fertilizers and their impact on the environment. The salinity significantly affects efficiency of N fertilizer in reclaimed tidal soil, and the soil pH may influence the conversion rate of ammonium to nitrate and ultimately affect nitrogen losses from the soil profile. Several results suggest that pH has important effects on recovery of fall-applied N in the spring if field conditions are favorable for leaching and denitrification except that effects of soil pH are not serious under unfavorable conditions for N loss by these mechanisms. Soil pH, therefore, deserves attention as an important factor in the newly reclaimed tidal soils with applying N. However, fate of N studies in a newly reclaimed tidal soils have been rarely studied, especially under the conditions of saline-sodic and high pH. Therefore, understanding the fate of nitrogen species transformed from urea treated into the reclaimed tidal soil is important for nutrient management and environmental quality. In this article, we reviewed yields of rice and fate of nitrogen with respect to the properties of reclaimed tidal soils.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.11 no.1
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• pp.63-68
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• 2013

To see if slaked lime and organic fertilizer applications to soil are useful as countermeasures for reducing $^{99}Tc$ concentrations in rice seeds after $^{99}Tc$ contamination of paddy fields, pot experiments were performed for two different paddy soils in a greenhouse. The upper soils for a depth of about 20 cm were treated with the agricultural materials and $^{99}Tc$ 15 d before transplanting. The effects were compared using the transfer factor (TF) defined as the ratio of the plant concentration to the soil concentration. In the case of control plants, TF values for brown rice in the two soils were $4.1{\times}10^{-4}$ and $4.3{\times}10^{-4}$. Of various types of the application, only the application of slaked lime at a lower dose (about 0.6 kg $m^{-2}$), which led to a 60% reduction in the TF value for one soil, seemed to be worth using as a countermeasure. Little effect of the same application was found in the other soil so it is important to determine the effect averaged for a number of soils. Organic fertilizer applications at both of two different doses increased the TF value. It is considered necessary to perform experiments for slake lime applications at doses lower than the above.

• Proceedings of the Mineralogical Society of Korea Conference
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• 1996.10a
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• pp.25-35
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• 1996

유황은 작물에는 양적으로 인산만큼 요구되고 자연계에서 질소와 비슷하게 순환한다. 한국 토양에서 유황의 결핍은 예측이 가능한데 이는 농민이 현재까지 함유황비료의 사용을 등한히 한데 기인된다. 그러나 최근 담배, 채소, 과수 등 경제작물을 재배하는 농가에서는 함유황 비료의 수량 증수와 품질 개선을 이해하고 선호하게 되었다. 더욱이 주요 도시의 아황산가스 배출이 점차 감소하는 것도 한 이유가 된다. 최근 논 토양 1,155점, 밭토양 498점, 시설 재배지 114점을 채취 분석 유효 유황함량을 조사하였다. '88년 1차 유황 심포지엄 성적과 비교하면 작물에 유효한 제일인산칼슘 침출유황은 논과 시설재배지토양에서 뚜렷이 감소되었으며 밭토양에서는 증가하였다. 유효 유황함량인 10mg S/kg 이하인 비율은 논 8.2, 밭 $5.2\%$이었다. 논 토양의 토성속, 배수, 퇴적양식, 지형 등이 논 토양의 유황함량과 밀접한 관계가 있었으나 밭에서는 이 관계가 뚜렷하지 못했다. 조립질이고 배수가 양호하며 잔적층에서 발달된 토양에서는 유황함량이 낮아 이를 개선할 필요가 있으며 토양중 시용유황의 행동에 대한 세밀한 연구가 요구된다.

• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.62-69
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• 1999

With increased utilization of chemical fertilizer, soil fertility is getting serious problem. As a result, using organic soil conditioner (woody wastes or sawdust compost) would be only solution to recover soil vitality. In this study, manufacturing and characteristics of organic soil conditioner from Shiitake bedlogs (woody wastes) were studied. Also, to investigate the effect of continuous application of this bedlog compost on growth of plants, growth tests for radish and tree seedlings were done. The results are as follows ; Analytical results of decayed and fresh wood materials showed almost same as its wood components. The mixing ratio of raw materials with the other filling materials is essential for the manufacturing as well as good quality of its compost during composting process. In this experiment, mixing 12kg of urea, 25kg of lime, 40kg of chicken shit, and small amount of fermentation aids corresponding to I ton of sawdust resulted in good composts. Their moisture contents were adjusted to about 55%. Temperature of pile, in composting process, rose after I week and kept about above $60^{\circ}C$ for certain period. They were turned two times, 30th and 59th day, respectively, after piling. This bedlog compost contained 81.7% of high organic matter, 1.4% of a little nitrogen, 6.75 of pH and 25 - 30 of C/N ratio. There were no harmful effect on germination and growth of plants, such as radish and softwood and hardwood seedlings. Concerned to the effect of bedlog compost on soil temperature, the compost did not affect plant growth by changing soil temperature abruptly, but compensated the soil temperature such as a little increasing on the early morning, a little decreasing on the mid-day or afternoon (pm 2:00), and increasing on the early evening (pm 6:00).

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.1
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• pp.32-37
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• 1986

Field experiments were carried out to investigate the effect of wollastonite and iron refinery slag on the paddy rice yield insandyloam soil in which available silica level is 56 ppm. The results are as follows: 1. Application of wollastonite and iron refinery slag reduced the tillering and the height of rice plant in the early growth stage, while promoted those in the late growth stage. 2. As the same amounts of wollastonite and iron refinery slag were applied, the effectiveness on yield increase was same between the two silicate fertilizers. 3. The recovery ratio as measured by absorbed $SiO_2$ on rice plant over applied $SiO_2$, was greater in wollastonite than in iron refinery slag. 4. The increasing of the ratio of $SiO_2$ over N absorbed in rice plant trends toward decreasing the infection rate of neck blast. 5. The left-over ratio of available $SiO_2$ in soil over applied $SiO_2$, was greater in iron refinery slag than in wollastonite. 6. As measured by silica soluble in 0.5 N-HCl solution, 1 kg application per 10a of both silicate fertilizers increased about 2.3 ppm in soil silica content after harvest, respectively.

• Journal of Korea Soil Environment Society
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• v.5 no.3
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• pp.17-23
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• 2001

The adsorption and movement characteristics of herbicide pendimethalin was studied in three kinds of soil, sandy loam, silty clay and loam. The results of the batch test and columnexperimentweresummarizedasfollows. The shaking time reached to the adsorption equilibrium of pendimethalin in soils was 6 hours. The adsorption rates of pendimethalin for sandy loam, silty clay and loam were 59.6%, 77.3% and 64.0%, respectively. The adsorption isotherms with the Freundlich equation showed better consistency than that with the Langmuir one. The adsorption coefficients of pendimethalin for soils were 8.0. 16.1 and 9.5. respectively. When breakthrough point was 0.05Co, the breakthrough times reached for soils were 256 minutes, 810 minutes and 420 minutes. respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.3
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• pp.209-216
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• 1987

The experiments were carried out in lab. as well as in pots, to develop the agricultural usage of water swellable polymer, a kind of polyacrylic acid(K-sorb) synthesized by the Korea Advanced Institute of Science & Technology (KAIST) recently. The changes of soil physical properties and the influences to crops were investigated with various levels of K-sorb. When the K-sorb mixed with soils and soaked up distilled water, the volume of soils increased with the increase of soil available water contents and increase of K-sorb application levels. The rate increase of soil available water was higher in the coarse textured soils than in the fine while the swelling rate of soil volume showed adverse tendencies. A positive linear regression was observed between the contents of available soil water and levels of K-sorb. K-sorb application decreased bulk density and hardness due to the increase of porosity after soybean cultivation. The permeability in coarser textured soils such as sandy and coarse loamy families was decreased with the increase of K-sorb but in the medium textured soils it was opposite. At higher levels of K-sorb, about 0.5%, the permeability abruptly decreased due to dispersion and vertical movement in silty soils, while it was not changed in fine clayey soils but has the same trend with silty soils. In the plot of 0.3% of K-sorb application, the growth of soybean such as number of pods and stem length etc. increased and the yield also increased about 1.2-1.8 times of control. The optimum amounts of K-sorb were slightly different according to soil texture but estimated from regression curves were about 0.2% to 0.35% of soils in dry weight bases.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.2
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• pp.95-100
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• 1982

The residual effect of silicate fertilizer (crushed slag from the steel industry) on rice yield was evaluated through 4-year field experiments. Applications of the silicate fertilizer at rate of 2500 kg/ha to Gangseo sandy loam soil (Fluvaquentic Eutrochrepts) very low in available silica increased the grain yield by 7 to 12% depending on the mesh size of the fertilizer in the first year. The yield in the fourth year showed no residual effect. Seventeen to eighteen months after the application, available silica content of the soil (1N-sodium acetate extractable) decreased down to 130 ppm which is a, base level for the silicate fertilizer application. Decreasing tendency of available silica concentration of the soil with time differed according to the mesh size of the silicate fertilizer applied. In 36 to 48 months after the application, the extractable silica content of the soil converged to 90 to 100 ppm.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.2
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• pp.59-64
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• 2006

To analyze the changes of soil physico-chemical properties after reclamation, we carried out an experiment for 75 samples of representative saline soils in South Korea. The more the years after reclamation is proceeded, the blighter the soil color is, soil horizon differentiation and structure is developed, but electrical conductivity(EC) decreased. After the soil survey, coarse textured soils were more quickly de-salined than the fine textured soils. In case of fine loamy textured Poseung series, it could be estimated that the series had Salic horizons in sub-order level of taxonomical classification. In other case of coarse loamy textured soil series, it could be estimated that the series had Sodic properties in sub-group level. Sodium contents of fine loamy textured soils were not decreased after reclamation, but those of coarse loamy textured Gwanghwal series reclaimed about 76 years ago were reclassified because of desalinization. To be desalined low to 4 dSm-1 of EC, it presumably takes about 108, or 12 years for fine loamy and coarse loamy textured soils, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.4 no.1
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• pp.101-107
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• 1971

1. 수도(水稻)의 생육기간(生育其間)만이라도 심수하(甚水下)에 있어야하는 논은 투수성(透水性)의 영향(影響)을 받아야 하고, 동영향(同影響)은 수도생육(水稻生育)과 관련(關聯)을 갖는다. 즉(卽) 투수성(透水性)이 클 경우(境遇)에는 물의 소비(消費)가 많을 뿐만이 아니라 영양분(營養分)의 유실(流失) 및 유효화(有效化)가 억제(抑制)되고, 투수성(透水性)이 적을 경우(境遇)에에는 심(甚)한 환원상태(還元狀態)의 발달(發達)로 유해성분(有害成分)이 집적(集積)되어 수도(水稻)의 생육(生育)은 해(害)를 입게된다. 이렇게 생각하면 투수성(透水性)으로 본 벼 생육(生肉)에 가장 적합(適合)한 토양조건(土壤條件)이 있을 것인바 이 조건(條件)은 토양(土壤)의 종류외(種類外)에도 수도(水稻)의 품종(品種)이나 생육시기(生育時期)에 따라 다른것이다. 2. 투수성(透水性)이 큰 토양(土壤)에는 잘 유거(流去)되지 않는 비료(肥料)(유기물비료(有機物肥料)나 용성연비(熔成憐肥) 등(等))를 쓸것이며, 투수성(透水性)이 적고 유해성분(有害成分)이 집적(集積)되기 쉬운 토양(土壤)에는 류산근(류硫酸根)이나 유기질(有機質) 비료등(肥料等) 유해성분(有害成分)의 집적(集積)을 증가(增加)할 우려가 있는 비료(肥料)의 시용(施用)을 삼가야 한다. 3. 기왕(旣往) 국내(國內)에서 실시(實施)한 시험결과(試驗結果)에 의(依)하면 중점토(重粘土)에서는 연산(憐酸), 중점토(重粘土)와 퇴화염토(退化鹽土)에서는 가리결핍(加里缺乏)을 일으키기 쉬운것 같으나 그 밖의 토양(土壤)에서는 뚜렷한 경향(傾向)이 인정(認定)되지 않는다. 4. 투수성(透水性)이 큰 토양(土壤)에서는 산적토(山赤土)를 객토(客土)하는 경우(境遇)가 많은 바 이때에는 금비(金肥) 특(特)히 질소질비료(窒素質肥料)를, 객토(客土)하지 않았을때 보다 많이 써야 하는것이 일반적(一般的)이다. 5. 투수성(透水性)이 약(弱)하고 유해성분(有害成分)이 집적(集積)되기 쉬운 논에는 우선(于先) 석회(石灰)(소석회(消石灰))를 시용(施用)하여 토양반응(土壤反應)을 높여야 하며 심(甚)한 노후답(老朽畓)이나 퇴화염토(退化鹽土)에는 석회(石灰)와 아울러 규산질(珪酸質) 비료(肥料)를 시용(施用)한 연후(然後)에 비료(肥料) 삼요소(三要素) 시용(施用)을 고려(考慮)해야 할 것이다. 산성(酸性)으로 기울어져있는 많은 우리나라 논 토양(土壤)에는 알칼리성(性) 비료(肥料)인 용성연비(熔成憐肥)를 시용(施用)하는 것이 효과적(效果的) 일것이다. 6. 소석회(消石灰)와 규산(珪酸)의 시용(施用)은 연산(憐酸)과 가리(加里)의 요구량(要求量)을 증가(增加) 할것이며 비료(肥料) 삼요소(三要素)에 대(對)한 수도(水稻)의 응수곡선(應酬曲線)의 모습을 기왕(旣往)의 것과 달리 할것이다.