• Korean Journal of Soil Science and Fertilizer
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• v.17 no.4
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• pp.363-370
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• 1984

In order to predict the possible fertilizer requirement from the K supplying capacity of soil, the relative K activity ratio, Kas/Kai and Gapon coefficients, KG. were determined for the soil samples before flooding and at heading stage of rice in pot experiment. These parameters assumed as the K supplying capacity of soils were discussed through correlation with other factors such as grain yields or the amounts of $K_2O$ uptake by the rice plant. The results may be summarized as follows: 1. The KGo values in soils before flooding were 7.8, 6.6, and 7.1, whereas the Kas/Kai values were 1.37, 1.26 and 2.11, respectively, in clay, loam and sandy loam soils. 2. The significant yield responses to the application of potassium fertilizer were observed whenever the KG values in soils at heading stage become larger to the original KG values, regardless of any levels of fertilizer application. 3. The linear correlations between the exchangeable cation ratios [Kex./(Ca+Mg) ex.:me/100g] in soils and the potassium activity ratios ($[K^+]/\sqrt{[Ca^{{+}{+}}+Mg^{{+}{+}}]}$: mole/l) in equilibrium solutions were observed with different linear gradients according to the soil properties. 4. The Kas/Kai in the soils, estimated prior to the experiment, showed high correlations with the grain yields or the amounts of $K_2O$ uptake in the all treatments, while the Kas/Kai and the KGo in the soils at heading stage showed high correlations with the grain yields or the amounts of $K_2O$ uptake in only N 15 Kg/10a treatments. 5. The Kas/Kai and the KGo values determined in the soil at heading stage of rice showed high negative correlation each other and they could be used as soil factors for predicting potassium fertilizer requirement.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.580-586
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• 1995

Soil temperatures at depths of 1~5cm are important to the germination and emergence of dry seeded-rice. An automated weather station was used to monitor the hourly weather parameters at Experiment Farm, Kyung Hee University from April 21 to May 30 in 1994. The data was analyzed to figure out the 24-hour temporal changes in air 1.5m above ground and soil temperatures under ground of 0, 2.5, 5, 10 and 20cm. The fluctuations of soil temperature were greatest at the soil surface and decreased with increasing depth. Mean soil temperatures at depth of 2.5cm were about 3$^{\circ}C$ higher than mean air temperatures during the observation period. Although mean soil temperatures at depth of 2.5cm during 10 or 15 days after April 21, May 1 and May 11 showed almost same temperatures, the distribution patterns of temperature regime were different from each other. Rice cultivars, Hwasung, Seohae, Nampung, IR60 and CR155, were seeded at depth of 2.5cm on April 21, May 1 and May 11, respectively. The periods of seedling emergence(PSE) varied in accordance with cultivars and seeding dates. PSE was correlated with accumulated daily mean air temperatures and accumulated hours classified by temperature regimes.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.337-342
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• 1991

A bacterium producing the antifungal compound KRF-001 isolated from soil was selected and identified as Bacillus subtilis. The antibiotic KRF-001 was active against various fungi. Effecacy of KRF-001 at various concentration for controlling leaf blast of rice in the paddy field was evaluated and compared with recommended rates of kasugamycin, blasticidin- s and tricyclazole. KRF-001 caused no irritation on the skin of rabbits and LD50 for mice was deduced more than 5000 mg/kg which indicates the possibility of low toxicity or no toxicity.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.462-462
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• 2011

1994년에 발효된 기후변화협약에서 우리나라는 선발 개도국으로 분류되어 온실가스 의무감축 대상국에서 제외되었으나 제2차 공약기간 (2013~2017년)부터는 온실가스 감축 의무이행이 불가피할 것으로 예상되어 그 대응책 마련이 시급한 실정이다. 현재 국내에서는 국제기준에 부합하는 온실가스 배출량 통계자료 구축을 위한 기초연구가 다양하게 수행되고 있으나 온실가스 감축을 위한 시나리오 설정이나 모의실험 연구는 계획 중이거나 시작 단계에 있다. 이 중 농경지에서의 온실가스 배출은 환경조건에 따라 온실가스를 배출하거나 흡수할 수 있는 양면성을 갖기 때문에 미래의 온실가스 배출을 예측하고 국내 실정에 맞는 저감방안을 수립하기 위해서는 다양한 조건을 적용하여 온실가스 배출량을 모의할 필요가 있다. 따라서 본 연구에서는 작물생육과 토양환경의 상호작용을 고려하여 농업생태계 내에서의 온실가스 배출을 모의하는 DNDC (Denitrification-Decomposition)를 이용하여 다양한 물관리 방식을 적용하여 벼 재배시 논에서의 온실가스 배출량을 산정하고 그 결과를 비교하고자 하였다. 물관리 방식에 따른 온실가스 배출 모의를 위해 관개시기를 조정하여 상시담수와 간단관개시의 시나리오를 적용하고, 담수심의 깊이에 따라 심수관개시와 최소 담수심 시나리오를 적용하여 온실가스 배출량을 산정하였다. 이는 향후 농경지를 대상으로 관개 방식 개선을 통해 온실가스 배출량을 감축하고 지속가능한 토지이용방안을 모색하는데 기초자료로 활용할 수 있을 것이라 판단된다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.3
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• pp.336-340
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• 1987

The objective of this experiment was to find out the effect of agro-chemicals on the lodging in paddy field. Sioz added into soil up to 130 ppm and K$_2$O applied 15kg/10a at land preparation. 2.4-D sprayed 250g/10a on the 30 days after transplanting and kitatchin G. applied 3kg/10a on the 30 days before heading. The most efficient agro-chemical to prevent lodging was kitatchin which applied 3kg/10a on the 30 days before heading. Generally, kitatchin and 2.4-D were reduced plant height and lodging index, but decreased grain yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.2
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• pp.61-67
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• 1978

Drainage furnished air to provide favorable soil environment forfice growth at the late stage. A heavier fertilizer application and a denser plant density increase. Yield and yield component element by root activities and various substence productive element under sub-drainage.

• Magazine of the Korean Society of Agricultural Engineers
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• v.33 no.2
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• pp.104-111
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• 1991

In Korea, small-scale reclaimed areas have been suffering from many problems because of the lack of comprehensive developing strategy although considerable investments have been inputed by the public sector since 1970's. For 3 reclaimed sites in Chonnam Province choser as case study areas, the analysis, the second attempt of widely-spanned studies on areal conditions, concentrated on their farming and economic conditions. Its results were as follows ; 1. Although farming pattern has been transferred to the full4ime rice cropping type by the creation of reclaimed paddy field, farming size in the areas has not been increased more than that in existing agricultural areas. This means that agricultural planning should be included in the initial stage of reclamation projects, especially with reference to the substantial enlargement of farming size. 2. Block parcelling of severely fragmented holdings in new and old lands should be carried out, which can make farming activities efficient and farming route shortened. In large-scale reclaimed areas, new village planning could be considered in its central zone for efficent farming. 3. Because soil in the areas contains much more salt and water than that in other areas, new design methodology should be introduced for the efficient use of agricultural machines in reclaimed areas. 4. There are deep-seated economic problems in reclaimed area, which have been caused by very poor level and agriculturally dominated structure of household income. These problems should motivate farmers to give up positive action for qualitative and quantitative improvement in farming.

• Journal of Biosystems Engineering
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• v.9 no.2
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• pp.8-18
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• 1984

To investigate the most important factors affecting the mobility of power tiller and to find the method which can be used for predicting the mobility of power tiller in soft paddy field, a series of field experiment was performed with two models of power tiller (8ps and 6ps diesel). From the results obtained throughout field experiment, the following conclusions were derived. 1. The wheel sinkage of power tiller during both traveling and field operations, which mainly influence the mobility, could be predicted from both plate ($50{\times}100mm$) sinkage and soil cone index (30-degree cone with 2 and $6cm^2$ base area). 2. Prediction of wheel sinkage from the rectangular plate sinkage was found to be more suitable compared with the cone index. 3. The upper limit of rectangular plate sinkage was found as 15 centimeter for operation of power tiller in muddy field which is equivalent of $1kg/cm^2$ of $2cm^2$ cone index value.

• Journal of Microbiology
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• v.41 no.4
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• pp.277-283
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• 2003

Haloaliphatic hydrocarbons have been widely used as solvents and ingredients of pesticides and herbicides. However, when these compounds contaminate the environment, they can be very hazardous to animals and humans because of their potential toxicity and carcinogenicity. Therefore, lots of studies have been made for microbial degradation of those pollutant chemicals. In this study, 11 bacterial strains capable of degrading 1,2-dichloroethane (1,2-DCA), 2-chloropropionic acid (2-CPA), 2,3-dichloropropionic acid (2,3-DCPA), and 2-monochloroacetic acid (2-MCA) by hydrolytic dechlorination under aerobic conditions were isolated from wastewaters and rice paddy soil samples. Their morphological and biochemical characteristics and their degradation capabilities of haloaliphatic hydrocarbons were examined. On the basis of the 16S rDNA sequences, 8 different kinds of microbial species, including Pseudomonas plecoglossicida, Xanthobacter flavus, Ralstonia eutropha, were identified. All of the isolated strains can degrade MCA. In particular, strains UE-2 and UE-15 degraded 1,2-DCA, and strain CA-11 degraded 2,3-DCPA, which are hardly degraded by other strains.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.4 s.31
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• pp.3-12
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• 2004

It is necessary to manage water resources in rural areas in order to achieve proper development of new water resources, sustainable usage and reasonable distribution. This paper aims to analyze multi-temporal Landsat-7 ETM+data for soil moisture that is essential for crops in Ahnsung area. The ETM data was also fused with KOMPSAT-1 images in order to be used as backdrop watershed maps at first. Multi-temporal Images showed also the characteristics of soil moisture distribution. Images taken in April showed that rice paddy had as low reflectance as artificial features. Compared with April scenes, those taken in Hay and June showed wetness index increased in the rice paddies. The mountainous areas have almost constant moisture index, so the difference between the dates was very low while reservoirs and livers had dramatic changes. We can calculate total potential areas of distribution of moisture content within the basin and estimate the areas being sensitive to drought. Finally we can point out the sites of small rice paddies lack of water and visualize their distribution within the same basin. It can be said that multi-temporal Landsat-7 ETM+ and KOMPSAT data can be used to show broad drought with quick and simple analysis. Drought sensitiveness maps may enable the decision makers on rural water to evaluate the risk of drought and to measure mitigation, accompanied with proper data on the hydrological and climatic drought.