• 한국토양비료학회지
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• 제51권1호
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• pp.61-70
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• 2018

This study was carried out to review and compare crop cultivations upon chemical properties of paddy soil and qualitative characteristics of rice in Sejong-city from a point of view of farming extension to rice farmers and to utilize the result of the study as a basic guideline for precise agricultural practice. The pH in soils of Sejong was about 6.1-6.6 and had no difference with an average pH of paddy soils in Chung-Nam with pH 6.1. However, the average of organic matter, calcium (Ca) and available silicate in Sejong was lower than the average of them in Chung-Nam. The yields of rice were higher in 2010 than in 2011 and 2012, and the protein contents of rice were the highest in 2011 while the lowest water contents of rice in 2011. The protein contents upon regions were the highest in 2011 with 6.1%, and the amylose contents were the highest in Yeondong-myun, Jeoneu-myun, and Yeonseo-myun in 2010 while Kumnam-myun and Jeondong-myun were the highest in 2012. With the increase of precipitation, the protein content level in rice was increased while the amylose content level tended to decrease. Correlations between the chemical properties of paddy soil and the quality of rice and between level of organic matter in soil and amylose contents were negative (r = -0.507), and the correlation between the moisture contents and amylose contents (r = 0.419) and between the water contents and whiteness (r = 0.485) were positive. Because the quantity and quality of rice yield is determined by the soil characteristics, the consultation to farmers for the proactive soil analysis and for the maintenance of stable level of pH, organic matter and available silicate based on historical results of analysis is highly recommended. Also, the analysis on the effect of the weather and the soil characteristics affecting the quality and quantity of rice would be another good way.

• 한국토양비료학회지
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• 제4권2호
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• pp.177-186
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• 1971

벼생육기간에 있어서 논토양에 시용된 퇴비 생집 등의 유기물 효과를 밝히기 위하여 시험했든 기존성적들을 요약하면 다음과 같다. 1. 토양개량제의 면에서 배수가 양호한 토양에서는 퇴비의 효과가 인정되었고 습답이나 배수불량한 논토양에서의 효과는 보지 못했다. 2. 생집의 효과는 토양조건에 따라 퇴비의 효과보다 한정되어 있으며 생집은 초기 벼생육을 억제하고 후기양분 보존 면에서 효과가 있었다. 3. 생집시용시의 수종문제점도 역시 논의되었다.

• Environmental Engineering Research
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• 제24권1호
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• pp.45-53
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• 2019

Water and soil properties in paddy fields subjected to organic and conventional farming were characterized over the rice cycle in South Korea. To achieve the goals of this study, we sampled and analyzed soil and water from 24 organic paddy plots and 11 conventional paddy plots in March, May, August, and October 2016. The results were analyzed using statistical analyses, including analysis of variance (ANOVA), cluster analysis, and principal component analysis. The ANOVA results showed that water content (WC), electrical conductivity (EC), organic matter (OM), and available phosphorus ($P_2O_5$) in soil varied significantly (p < 0.01) depending on the farming method. Higher OM, EC, and $P_2O_5$ of soil were observed in the conventional paddies than in the organic paddies. All soil properties, except pH and ammonium, depended on seasonal variation. Cluster analysis revealed that soil properties in May were distinctly separated from those in other seasons mainly due to basal fertilization. The principal component analysis distinguished the soil properties in different seasons, but such a distinction was not observed between the soil properties in organic and conventional paddies. Low contents of WC, OM, and total N were observed in March. High concentrations of nitrate and total P were observed in May, but these were low in August and October. The soils from October were also characterized by high concentrations of EC and $P_2O_5$. These results indicate that the sampling time for soil and water can significantly influence the evaluation of soil properties with different farming methods.

• 한국토양비료학회지
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• 제44권2호
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• pp.221-227
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• 2011

논 토양에서 청보리, 자운영과 트리티케일을 시용하고 벼생육초기에 토양 미생물 생태계의 변화에 미치는 영향을 검토하였다. 녹비를 시용한 처리구는 관행에 비해 토양 유기물 함량은 유의적으로 증가하였으나 토양의 나트륨 함량은 유의적인 감소를 나타냈다. 내생균근균의 함량과 구성비율은 녹비 시용으로 관행 보다 유의적으로 높아졌으며 특히 청보리 처리구가 가장 높았다. 또한 토양의 그람음성 세균과 그람양성 세균의 비율과 불포화지방산과 포화지방산 함량의 비율은 청보리 처리구가 다른 처리구에 비해 유의적인 증가를 보였다. 그리고 주성분 분석에서 PC 1에 가장 큰 영향을 미친 미생물 군집은 그람음성 세균인 것으로 나타났으며 청보리 처리구는 관행과 가장 큰 차이를 나타냈다. 이러한 결과를 종합한 결과 청보리는 논 토양의 초기 미생물 다양성을 증대시킬 수 있는 최적의 녹비작물로 판단된다.

• 한국토양비료학회지
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• 제49권1호
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• pp.7-11
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• 2016

Winter crops have been recognized as an alternative to soil management for fertility and crop productivity in paddy soil. Recently, rape has been produced at winter season and there is little research results on reduction of N fertilizer by adding rape residues for rice cultivation. In this study, we investigated the productivity and quality of rice by applying with 0, 27, 63, $90kg\;ha^{-1}$ of N fertilizer after input of rape residues into soil for two years. The highest yield of rice was average $4.68Mg\;ha^{-1}$ at the treatment applied with the $90kg\;N\;ha^{-1}$ with rape residue. It was reduced to N rate from 31.6 to $43.2kg\;N\;ha^{-1}$ in comparison to $4.53Mg\;ha^{-1}$ of maximum yield in treatment added $90kg\;N\;ha^{-1}$ with rape. Amylose content in rice was similar among treatments with/without rape residue, but protein content was lower in treatment with rape residue than in those without rape residue. In conclusion, input of rape residue in rice cultivation could be alternative to reduction of N fertilization and improvement of quality by adjusting rice productivity in paddy soil under cropping system.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권4호
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• pp.50-59
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• 2016

Spatial and temporal changes in nitrification activities and distribution of microbial population of ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) in paddy soils were investigated. Soil samples were collected in March and October 2015 from rice paddy with and without the presence of confined animal feeding operations. Incubation experiments and quantitative polymerase chain reaction showed that AOA's contribution to nitrification kinetics was much higher in locations where organic nitrogen in animal waste is expected to significantly contribute to overall nitrogen budget, and temporal variations in nitrification kinetics were much smaller for AOA than AOB. These differences were interpreted to indicate that different microbial responses of two microbial populations to the types and concentrations of nitrogen substrates were the main determining factors of nitrification processes in the paddy soils. The copy numbers of ammonium monooxygenase gene showed that AOA colonized the paddy soils in higher numbers than AOB with stable distribution while AOB showed variation especially in March. Although small in numbers, AOB population turned out to exert more influence on nitrification potential than AOA, which was attributed to higher fluctuation in AOB cell numbers and nitrification reaction rate per cells.

• 한국토양비료학회지
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• 제37권6호
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• pp.357-364
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• 2004

우리나라 논과 밭토양의 질의 현황에 대한 평가방법을 개발하고자 2000년부터 2003년까지 실시한 농업환경변동조사사업의 결과를 이용하여 세부지표 즉 토양의 주요특성의 선정, 선정된 각 지표의 점수화 또는 등급화와 정량화 방법과 각 세부지표를 종합하여 한개의 토양의 질 지표로 만드는 방법을 검토하였다 한편, 본 시안을 이용하여 전국수준에서 우리나라 논 밭 시설원예지 토양의 질 현황에 대한 평가를 시도한 결과 논토양은 매우 높음, 밭토양은 높음, 그리고 시설원예지 토양은 보통으로 나타났다.

• 한국환경복원기술학회지
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• 제5권3호
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• pp.1-8
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• 2002

Clayey paddy soils should be mixed with other good coarse soils to be used as a material for the lining, or, embankment. However, it has been difficult to separate soil particles from each other because of the internal cohesion in the soil gradation(separation) characteristics of the fine soil were investigated by various laboratory tests including the slaking durability test. Degradation rate of the soil were dependent upon the clay content and the initial water content before the submergence. The amount of degradations decreased as initial water content increased with exponential functions. The dried specimens separated into the particles after 24 hours of the submergence and specimens which water contents were less than 10% also separated into the particles after 2, or 3 days of the submergence. Compaction curves and the unconfined strength were not varied before and after the submergence. However, unconfined strength decreased as water content increased.

• 한국토양비료학회지
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• 제49권6호
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• pp.655-661
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• 2016

Relationships between saturated conductivity (Ks) and separate contents were evaluated from 44 soil series of arable lands: 18 for paddy fields and 26 for upland crop fields. Saturated hydraulic conductivities of A, B, and C horizons were determined with tension infiltrometer and Guelph permeameter in situ. Sand, silt, clay, and organic matter content of each horizon were analyzed. Based on correlation analysis, sand separate had a positive relationship with Ks for both paddy (r=0.27, p=0.017) and upland fields (r=0.24. p=0.030). Clay content had a negative relationship with Ks for paddy soils (r=-0.32, p=0.005) while significant correlation between them was not found for upland crop fields (r=-0.20, p=0.07). Organic matter content showed a positive relationship with Ks only for upland crop fields (r=0.33, p=0.002). Due to low correlation coefficients between separate contents and Ks, performance of pedotransfer functions was not enough to estimate Ks. It implies that hydraulic properties of arable lands were affected by other factors rather than particle characteristics. Platy structure and plow pan were suggested to limit Ks of paddy fields. Soil compaction and diversity of parent materials were proposed to influence Ks of upland crop fields. It suggests that genetic processes and artificial managements should be included in pedotransfer functions to estimate hydraulic properties appropriately.

• 한국토양비료학회지
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• 제44권6호
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• pp.1314-1319
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• 2011

This study was carried out to investigate the surface soil organic carbon fractions affecting by different land use types, including needle-leaf forest (FN), broad-leaf forest (FB), pasture, annual upland cropping land (upland), and paddy rice land (paddy). We chose seven regions across Korean inland, considering sea level altitude, and measured soil organic carbon content and physico-chemical properties such as bulk density at a depth of 0~15 cm using core samples in April for the each land use type. In addition, labile organic carbon fractions in soil including light fraction and hot water extractable carbon were investigated. From this study, organic carbon storage (Mg C per ha) in the upper 15-cm soils was highest in FB (37.8), and decreased in the order of pasture (29.1), FN (28.8), paddy (21.9), and upland crop (19.9). In forest, more than 20% of soil organic carbon existed as light fraction, the free organic matter. Hot-water extractable carbon contents of soils in five land use types were lower than 7% of their soil organic carbon content.