• Weed & Turfgrass Science
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• 제1권4호
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• pp.1-5
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• 2012

번거로운 토양 종자은행 조사를 위해 간편한 모니터링 방법을 고안하였으며 이를 이용하여 경운과 무경운에 따른 토양내 잡초종자의 수직적 분포 양상을 관찰하였다. 본 시험은 강원도 화천의 유기농 옥수수 포장에서 수행되었다. 포장의 조성은 2010년부터 경운과 무경운 조건으로 2년간 조성된 무경운 포장에서 30 cm 깊이의 비파괴 토양 시료를 채취한 후 그 안에서 발생하는 잡초를 헤아려 종자의 토양 분포정도를 조사하였다. 토양속 잡초 종자의 분포는 경운구의 경우 15 cm 이내에 75%의 종자가 분포되어 있는 등 30 cm 깊이까지 대체로 고르게 분포되고 있었던 반면 무경운 조건에서는 15 cm 이내에 85% 이상의 종자가, 20 cm 이내에 93%의 종자가 분포되어 대체로 토양 표면에 집중되었다. 한편 잡초의 발생초종수와 개체수는 경운구가 무경운구에 비해 3배나 많은 양이 발생되었으며 주요 우점초종은 돌피, 석류풀, 바랭이 등의 일년생 초종이었다.

• 한국토양비료학회지
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• 제31권3호
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• pp.233-237
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• 1998

토양에 시용되는 각종 폐유기물들의 토양중 질소 무기화율을 알아보기 위하여 3종의 폐유기물(A:도시고형폐기물+하수슬러지, B:목재잔사, C:목재잔사+하수슬러지)를 토양에 처리한 뒤 12주 동안 $25^{\circ}C$ 호기조건에서 질소 무기화율을 조사한 결과, 초기 질산화율은 C 처리구가 다른 처리구에 비하여 높았다. 또한 무기화된 총질소량은 C 처리구에서 가장 많았으나 실험기간 동안의 질소 무기화율과 질산화율은 무처리구에서 높게 나타났다.

• 한국토양비료학회지
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• 제50권1호
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• pp.12-20
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• 2017

Various types of organic materials could affect differently immobilization of cadmium (Cd) and its uptake by plant grown in soil. Therefore, this study was conducted to evaluate effect of different organic materials in reducing Cd phytoextractability in contaminated arable soil. To do this, rice straw and composted manure were selected as organic materials and applied at the rate of 0, 15, 30, and $45Mg\;ha^{-1}$ in Cd contaminated arable soil with $6.5mg\;kg^{-1}$ of total Cd. Radish (Raphanus sativa L.) was seeded and grown for 50 days to evaluate Cd phytoavailability with different organic materials. Composted manure was more effective to decrease $1M\;NH_4OAc$ extractable Cd concentration and increase pH of soil than rice straw. $One\;M\;NH_4OAc$ extractable Cd concentration significantly decreased with increasing application rate of composted manure. Tendency of Cd uptake by radish plant with application of different organic materials was similar to that of $1M\;NH_4OAc$ extractable Cd concentration and soil pH. Changes of soil pH with application of straw and composted might be one of factors to determine extractability and phytoavailability of Cd in this study. Radish yield significantly increased with up to $45Mg\;ha^{-1}$ of composted manure application but did not with straw application. In the view point of Cd phytoextractability and plant productivity, it is recommended to apply composted manure rather than straw in Cd contaminated arable soil.

• 한국환경과학회지
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• 제8권1호
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• pp.69-74
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• 1999

Soil properties which affect the retention of Pb(I) were investigated in the laboratory. It was determined, through selective removal, that organic matter and Fe-oxides are of lesser importance in influencing Pb retention than are soil clay minerals. The following trend : clays ＞ organic matter ＞ Fe-oxides represents the relative importance of each constituent in the adsorption of Pb by soils. The consistently greater Pb uptake by surface over subsurface samples was apparently due to differences in organic matter content, inasmuch as organic matter removal from both resulted in similar adsorption characteristics. All five soils stooled exhibited a pH-dependent trend of adsorption. The extent of Pb adsorption was least at low pH values(4~5), was maximum in the neutral pH range, and leveled off or diminished under more alkaline conditions. There was no strong correlation between Pb uptake and soil cation exchange capacity as routinely measured by the NH$_4$OAc method. A knowledge of clay mineralogy in conjunction with soil pH is suggested as being the most reliable guide to predicting Pb retention by soils.

• Journal of Microbiology and Biotechnology
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• 제32권10호
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• pp.1292-1298
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• 2022

Soil autotrophic bacterial communities play a significant role in the soil carbon (C) cycle in paddy fields, but little is known about how rhizosphere soil microorganisms respond to different long-term (35 years) fertilization practices under double rice cropping ecosystems in southern China. Here, we investigated the variation characteristics of rhizosphere soil RubisCO gene cbbL in the double rice ecosystems of in southern China where such fertilization practices are used. For this experiment we set up the following fertilizer regime: without any fertilizer input as a control (CK), inorganic fertilizer (MF), straw returning (RF), and organic and inorganic fertilizer (OM). We found that abundances of cbbL, 16S rRNA genes and RubisCO activity in rhizosphere soil with OM, RF and MF treatments were significantly higher than that of CK treatment. The abundances of cbbL and 16S rRNA genes in rhizosphere soil with OM treatment were 5.46 and 3.64 times higher than that of CK treatment, respectively. Rhizosphere soil RubisCO activity with OM and RF treatments increased by 50.56 and 45.22%, compared to CK treatment. Shannon and Chao1 indices for rhizosphere soil cbbL libraries with RF and OM treatments increased by 44.28, 28.56, 29.60, and 23.13% compared to CK treatment. Rhizosphere soil cbbL sequences with MF, RF and OM treatments mainly belonged to Variovorax paradoxus, uncultured proteobacterium, Ralstonia pickettii, Thermononospora curvata, and Azoarcus sp.KH33C. Meanwhile, cbbL-carrying bacterial composition was obviously influenced by soil bulk density, rhizosphere soil dissolved organic C, soil organic C, and microbial biomass C contents. Fertilizer practices were the principal factor influencing rhizosphere soil cbbL-carrying bacterial communities. These results showed that rhizosphere soil autotrophic bacterial communities were significantly changed under conditions of different long-term fertilization practices Therefore, increasing rhizosphere soil autotrophic bacteria community with crop residue and organic manure practices was found to be beneficial for management of double rice ecosystems in southern China.

• 한국토양비료학회지
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• 제45권6호
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• pp.936-942
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• 2012

This review was to elucidate the fate of Bentazon(3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one-2,2-dioxide) and its metabolites in soil. Bentazon is rapidly degraded to form polar metabolites which are mostly adsorbed to soil components, such as humin or fulvic acid, as non extractable forms and mineralized into $CO_2$ by light or micro-organisms in both aerobic or nonaerobic condition. The degradation of Bentazon is dependent on the rate of organic matters in soil and the use of land for the tillage. The degradation rate is decreased as the amount of organic matters in soil increases and if the land is under use for tillage. Sorption and mobility of Bentazon depends on soil pH and the content of organic matters in soil. Usually, the sorption of the metabolites of Bentazon is decreased with increase in the mobility and pH. Almost all of Bentazon is degraded within rhizosphere or forms conjugate bonds with soil organic matters before it reaches to the ground water.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1175-1180
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• 2008

This study explored the compacition characteristics of organic weathered soils. Weathered soils were collected around the Gwangju University in Jinwol-dong, Gwangju city, and coal was used as organic material. Weathered soils were mixed with coal so that the ratio of organic elements against mixed soil can be 0%, 25%, 50%, and 75% respectively. Compaction tests were carried out on these organic mixture soils in different ratios of organic materials. And soap water instead of water in compaction tests was used. Through this study, We knew that the bigger the organic material ratio was, the more the optimum moisture content increased and the less the maximum dry unit weight reduced. In case of using small compaction energy, using soap water instead of water improved the compaction efficiency a little.

• Journal of Biosystems Engineering
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• 제27권3호
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• pp.259-266
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• 2002

It is crucial to know spatial soil variability for precision farming. However, it is time-consuming, and difficult to measure spatial soil properties. Therefore, there are needs fur sensing technology to estimate spatial soil variability, and for electronic mapping technology to store, manipulate and process the sampled data. This research was conducted to develop a real-time soil organic matter sensor and an electronic mapping system. A soil organic matter sensor was developed with a spectrophotometer in the 900∼1,700 nm range. It was designed in a penetrator type to measure reflectance of soil at 15cm depth. The signal was calibrated with organic matter content (OMC) of the soil which was sampled in the field. The OMC was measured by the Walkeley-Black method. The soil OMCs were ranged from 0.07 to 7.96%. Statistical partial least square and principle component regression analyses were used as calibration methods. Coefficient of determination, standard error prediction and bias were 0.85 0.72 and -0.13, respectively. The electronic mapping system was consisted of the soil OMC sensor, a DGPS, a database and a makeshift vehicle. An algorithm was developed to acquire data on sampling position and its OMC and to store the data in the database. Fifty samples in fields were taken to make an N-fertilizer dosage map. Mean absolute error of these data was 0.59. The Kring method was used to interpolate data between sampling nodes. The interpolated data was used to make a soil OMC map. Also an N-fertilizer dosage map was drawn using the soil OMC map. The N-fertilizer dosage was determined by the fertilizing equation recommended by National Institute of Agricultural Science and Technology in Korea. Use of the N-fertilizer dosage map would increase precision fertilization up to 91% compared with conventional fertilization. Therefore, the developed electronic mapping system was feasible to not only precision determination of N-fertilizer dosage, but also reduction of environmental pollution.

• 한국가스학회지
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• 제21권1호
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• pp.1-5
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• 2017

독성가스 사고 시 토양 침적은 사고피해범위에 영향을 미치는 주요 변수이다. 본 연구에서는 토양의 깊이 및 유기물 함량 비율이 독성가스 염소의 토양 침적 특성에 미치는 영향을 연구하였다. 실험에 이용된 장치로는 미국의 Air Force Research Laboratory에서 구축한 장치를 벤치마킹하였다. 다양한 합성토양을 이용해 유기물의 함량을 변화시키면서 토양 침적실험을 진행하였다. 다양한 합성토양에 일정 농도의 염소를 노출시킨 후, 염소 침적의 정도를 정량화하기 위해 음이온 크로마토그래피를 이용하여 침적량을 측정하였다. 그 결과, 토양 표면에서의 침적량 변화에 비해 깊이에 따른 침적량의 변화 경향은 볼 수 없었으나, 염소 노출 시간에 따른 표면 침적량의 차이는 증가함을 확인 할 수 있었다. 또한, 유기물 함량에 따른 침적량은 유기물 함량이 증가함에 따라 비례관계를 보였다. 토양 표면에서의 염소 침적량의 증가는 주로 토양 내 유기물 함량에 의존함을 확인하였다.

• 한국환경과학회지
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• 제23권11호
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• pp.1827-1833
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• 2014

This study has been carried out to present the valuation system of soil carbon sequestration potentials of soil in accordance with the new climate change scenarios(RCP). For that, by analyzing variation of soil carbon of the each type of agricultural land use, it aims to develop technology to increase the amount of carbon emissions and sequestration. Among the factors which affects the estimation of determining the soil carbon model and influence power after the measurement on soil organic carbon, under the center of a causal relationship between the explanatory variables this study were investigated. Chemical fertilizers (NPK) decreased with increasing the amount of soil organic carbon and as with the first experimental results, when cultivating rice than pepper, the fact that soil organic carbon content increased has been found out. The higher the carbon dioxide concentration, the higher the amount of organic carbon in the soil and this result is reliable under a 10% significance level. On the other hand, soil organic carbon, humus carbon and hot water extractable carbon has been found out that was not affected the soils depth, sames as the result of the first year. The higher concentration of carbon dioxide, the higher carbon content of humus and hot water extractable carbon content. According to IPCC 2006 Guidelines and the new climate change scenario RCP 4.5 and the measurement results of the total amount of soil organic carbon to the crops due to abnormal climate weather, 1% increase in atmospheric carbon dioxide concentration was found to be small when compared to the growing rate of increasing 0.01058% of organic carbon in the soil.