• 한국토양비료학회지
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• 제40권4호
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• pp.326-329
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• 2007

Quantifying soil organic carbon (SOC) has long been considered to improve our understanding of soil productivity, soil carbon dynamics, and soil quality. And also SOC could contribute as a major soil management factor for prescribing fertilizers and controlling of soil erosion and runoff. Reducing tillage intensity has been recommended to sequester SOC into soil. On the other hand, determination of traditional SOC could barely identify the tillage practices effect. Physical soil fractionation has been reported to improve interpretation of soil tillage practices impact on SOC dynamics. However, most of these researches were focused onupland soils and few researches were conducted on paddy soils. Therefore, the objective of this research was to evaluate paddy soil tillage impact on SOC by physical soil fractionation. Soils were sampled in conventional-tillage (CT), partial-tillage (PT), no-tillage (NT), and shallow-tillage (ST)plots at the National Institute of Crop Science research farm. Samples were obtained at the three sampling depth with 7.5-cm increment from the surface and were sieved with 0.25- and 0.053-mm screen. Soil organic carbon was determined by wet combustion method. Significant difference of SOC contentwas found among sampling soil depth and soil particle size. SOC content tended to increase at the ST plot with increasing size of soil particle fraction. We conclude that quantifying soil organic carbon by physical soil particle fractionation could improve understanding of SOC dynamics by soil tillage practices.

• 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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• 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.

• 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.

• 한국환경농학회지
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• 제30권4호
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• pp.367-376
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• 2011

논 토양의 미생물 생태 다양성을 조사하기 위한 효과적인 방법으로 qRT-PCR을 적용하고자 본 연구를 수행하였다. 논 토양 미생물의 gDNA를 분리하기 위하여 Mo Bio kit를 사용한 효과적이고 안정적인 gDNA 분리 방법을 확립하였다. 논 토양 미생물 다양성을 qRT-PCR로 검출하기 위하여 bacteria를 세분한 ${\alpha}$-Proteobacteria, ${\beta}$-Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes 다섯 가지 문과 전체 bacteria, 전체 fungi를 구분할 수 있는 특이 primer set을 선정하여 다양한 조건의 시험을 통하여 최종 조건을 확립하였으며 재현성 실험을 통하여 방법의 유의성을 검증하였다.

• 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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• 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.

• Journal of Microbiology and Biotechnology
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• 제20권1호
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• pp.187-192
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• 2010

In order to monitor the possibility of horizontal gene transfer between transgenic rice and microorganisms in a paddy rice field, the gene flow from a bifunctional fusion (TPSP) rice containing trehalose-6-phosphate synthase and phosphatase to microorganisms in soils was investigated. The soil samples collected from the paddy rice field during June 2004 to March 2006 were investigated by multiplex PCR, Southern hybridization, and amplified fragment length polymorphism (AFLP). The TPSP gene from soil genomic DNAs was not detected by PCR. Soil genomic DNAs did not show homologies on the Southern blotting data, indicating that gene transfer did not occur during the last two years in the paddy rice field. In addition, the AFLP band patterns produced by soil genomic DNAs from both transgenic and non-transgenic rice fields appeared similar to each other when analyzed by the NTSYSpc program. Thus, these data suggest that transgenic rice does not give a significant impact on the communities of soil microorganisms, although long-term observation may be needed.

• 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.

• 한국토양비료학회지
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• 제45권2호
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• pp.143-148
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• 2012

경남지역 논토양의 양분관리를 위한 기초자료를 제공하기 위해 260 지점의 화학성분 변동을 1999년부터 2011년까지 4년 주기로 분석하였다. 논토양 pH, 유기물 함량, 유효인산 함량, 유효규산 함량, 치환성 칼슘 및 마그네슘 함량은 1999년에 비해 2011년에 유의적으로 증가하였다. 유기물 함량의 초과비율은 1999년 40.0%, 2003년 30.4%, 2007년 48.5%, 2011년 50.8%로 증가하였다. 유효인산 함량의 초과비율은 1999년 55.0%, 2003년 57.7%, 2007년 52.7%, 2011년 63.5%로 2배 이상 과잉 집적되었다. 유기물 함량은 홍적대지에서 가장 높았고 유효인산 함량은 산록경사지에서 가장 높았다. 논토양의 통계분석과 주성분 분석을 통하여 경남지역 논토양의 유효인산 함량은 지형별 화학특성을 구별할 수 있는 중요인자로 판단되었다.