• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.1
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• pp.104-115
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• 1992

The rice culture techniques included 'Jodosukyungbeob'(旱稻水耕法 : culture techniques of early-ripening paddy rice), 'Mandosukyungbeob' (晩稻水耕法) : culture techniques of late-Ripening paddy rice 'Handobeob'(旱稻＆lt;山稻＆gt;法 : culture techniques of upland rice), 'Myojongbeob'(苗種法 : culture techniques of paddy rice by transplanting), 'Kunangbeob'(乾秧法 : culture techniques of rice by transplanting which rears seeding in dry paddy) and 'Sudogunpanongbeob'(水稻乾播農法 : culture techniques of paddy rice seeding in dry field). Especially, 'Kunangbeob' and 'Sudogunpanongbeob' were originally developed in Korea as seen in 1600s(Kyoungje : 經濟) and early 1800s (Yoji : 要旨). In 'Jodosukyungbeob' it took 9 days for seed dipping, water-sprouting and prevent damage by birds, each for 3 days in China, but in Korea seed dipping in water took 3 days and the rest of the procedures were flexibly established. In matured soils, practices were fall plowing right after harvest, recognition of effective tillering and additional fertilization use of human manure, and stimulation of sprouting by lime application. The unique culture techniques adequate for Korean situations were practiced, which included weed control after draining accurately for 3 to 4 times, draining at mid season for improving wind and drought tolerance, rice harvesting at appropriate time for preventing grain shattering, and seeding in rows. 'Mandosukyungbeob' was improved techniques contrast to those of China, and the major contents were selection of proper varieties, good stand establishment by seeding high rates, induction of vigorous tillers, and adoption of 'Jokjongbeob'(足種法 : seeding method by foot). Also, one of the most prominent rice cultures by our ancestors was 'Kunpanongbeob' that was systemized form habitual practice of Pyongan Province. The unique technique actualized was 'Hando [旱稻(山稻)]' culture technique which was the combinations of 'Jokjongbeob', root stimulation method, and disaster-tolerant mixture cropping with adoptation of variety theory, although it was originated from China. The transplanting techniques has come before 'Jikseol'($\ulcorner$直說$\lrcorner$) and its merits were sufficiently realized. However, this method was basically prohibited from the early Chosun dynasty because extremely bad harvest was expected under drought conditions and insufficient conditions of water storage. But, it was permitted in the areas that contained water all the times and in case of large-scale farming especially. Most of rice culture was transplanted in the end of the Chosun dynasty because transplanting was continuously spreaded in the three southern provinces of Korea. Under these circumstances, transplanting technique was improved from the early to the end of the Chosun dynasty by weed control, fertilizing, water management, and quadratic transplanting. Based on these techniques, agricultural productivity was improved 5 times by that time. 'Kunpanongbeob' was created and developed properly for Korean conditions that is dry in early season and flooding in late season. This was successively developed and established into transplanting technique of nursery seedling.

• Korean Journal of Environment and Ecology
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• v.30 no.6
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• pp.939-961
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• 2016

For effective conservation of endangered wild plants, it is necessary to understand their interactions with environmental factors in each habitat together with life traits of target species. First, the characteristics of their distribution were investigated followed by their monitoring for 4 years focusing on the habitats in the lagoon. Also, their life traits were compared including production of hibernacles, fruits, and seeds by the soil fertilization and light intensities. Next, the information on the species was secured by germination experiment using the generated seeds from the cultivation experiment. The habitat of Glaux maritima var. obtusifolia Fernald in Korea was located in the rear edge of the worldwide distribution and its four habitats were isolated and distributed far away each other. Two of them were located in small salt-marsh and fine sand estuaries formed in the rocky area of the seashore, and the other two were inhabited with the sandy soil in the lagoon which was connected by river-mouth to the sea. Glaux maritima var. obtusifolia Fernald tends to be distributed in the sites where the establishment and growth of the competitor were inhibited by salinity, periodic flooding, and lower layer of the soil to extend a roots. It maintained its population by recruitments of hibernacles and seedling. The production of hibernacle was assumed to be affected by the particle consist of the sand together with organic matters in the soil. Seedling recruitment was observed only in the salt-marsh area located in the rear sites of sand ridge where was the shore of the lagoon. Glaux maritima var. obtusifolia Fernald was observed to have different threatening factors by each population. Its population in Pohang seemed the sedimentation of fine sand which affected the recruitment of hibernacles had been eroded due to the construction of the coastal road. The population in Ulsan appeared rapid expansion of competitor and reduction of its distribution area due to the interruption of eluted water supplied to the habitat. On the other hand, the habitat in the lagoon maintained the population relatively stable. Especially, the population in Songji-ho was determined to be the most stable one. To sustain the population of Glaux maritima var. obtusifolia Fernald distributed in the lagoon, it is suggested that the wide ranged scale of conservational activities is necessary to maintain the mechanisms including the entrance of seawater which belongs to the lagoon, and periodic flooding.

• Economic and Environmental Geology
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• v.38 no.6 s.175
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• pp.633-642
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• 2005

We present the sedimentary sequence and distribution pattern of the late Holocene muddy deposits in the northern East China Sea shelf using the high-resolution 'Chirp' profiles. The seismic sedimentary sequence overlying acoustic basement (basal reflector-B) can be divided into two depositional units (Unit 1 and 2) bounded by erosional bounding surface (mid reflector-M). The lower Unit 1 above basal reflector-H is characterized by the acoustically parallel to subparallel reflections and channel-fill facies. The upper Unit 2, up to 7 m in thickness, shows seismically semi-transparent seismic facies and lenticular body form. On the base of sequence stratigraphic concept, these two sediment units have developed during transgression and highstand period, respectively, since the last sea-level lowstand. The transgressive systems tract (Unit 1) lie directly on the sequence boundary (reflector B) that have farmed during the last glacial maximum. The transgressive systems tract in this study consists mostly of complex of delta, fluvial, and tidal deposits within the incised valley estuary system. The maximum flooding surface (reflector M) corresponding to the top surface of transgressive systems tract is obviously characterized by erosional depression. The highstand systems tract (Unit 2) above maximum flooding surface is made up of the mud patch filled with the erosional depression. The high-stand mud deposits showing a circle shape just like a typhoon symbol locates about 140 km off the south of Cheju Island with water depth of $60\~90m$. Coverage area and total sediment volume of the mud deposits are about $3,200km^2$ and $10.7\times10^9\;m^3$, respectively. The origin of the mud patch is interpreted as a result of accumulating suspended sediments derived from the paleo-Yellow and/or Yangtze Rivers. The circular distribution pattern of the mud patch appears to be largely controlled by the presence of cyclonic eddy in the northern East China Sea.

• Clean Technology
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• v.26 no.2
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• pp.151-157
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• 2020

Rapid urbanization has elevated the risk of urban flooding due to the increase in the impervious surface, causing environmental disasters and environmental pollution problems, such as lowering the groundwater level and increasing water pollution. In Korea, low impact development (LID) techniques have been introduced to minimize these environmental impacts and maintain the water cycle soundness. However, most small-scale development projects are in blind spots because there is no legal basis for rainfall runoff management. Small-scale development projects that increase the surface runoff of rainwater are required to mandate the application of LID facilities in accordance with the polluters' responsibility principle. Therefore, it is necessary to implement a preliminary consultation system for water cycle recovery. This study focuses on the cost-benefit analysis on the application of LID techniques for small-scale development projects. The scale of nationwide small-scale development projects used for cost-benefit analysis were defined as buildings with a land area of more than 1,000 ㎡ or a total floor area of 1,500 ㎡. As a result of analyzing the cost-benefits from the installation of LID facilities, they were found to be much lower than the economic standard value of 1. This might be due to the high cost of facilities compared to the scale of the project. However, considering the overall environmental value of improving the water environment and air quality by the installation of LID facilities and the publicity of reducing the operating cost of sewage treatment facilities, the introduction of a prior consultation for small-scale development projects is inevitable. In the future, institutional and financial support from local governments is required to improve the cost-benefits with the introduction of a prior consultation for small-scale development projects.

• Journal of the Korean GEO-environmental Society
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• v.13 no.1
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• pp.45-51
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• 2012

This article aims to find method to mix a harmless hardening agent and soil generated during construction to make paving materials. The main purpose of this research is to get rid of the harmfulness(Chromium (VI), etc.) of cement which has been generally and frequently used as a hardening agent and strengthen it so that it can be used for the general foundation solidification and stabilization of civil engineering/construction structures such as dredging soil treatment, marine structure foundation treatment, surface soil stabilization, and river bank erosion prevention. NSS(Natural Stabilizer Soil) used for this study takes as its chief ingredient the mixture of lime and staple fibers extracted from natural fibers. It increases the shearing strength of soil that it improves the support and durability of the foundation and prevents flooding and frost as well. The pH measured to know its eco-friendliness was 6.67~7.15, and according to the migration testing, only Pb and CN were lower than the standards, so it can be said that NSS has almost no harmful components in it. According to the result of uniaxial strength testing, when the mixture ratio of weathered soil to NSS was 6%, about 1,850kpa strength was expressed. And according to the result of CBR. testing to figure out its appropriateness as a paving material, the CBR of the foundation was 4%~6%. But when the mixture ratio of NSS is over 6%, the water immersion CBR. is over 100%; thus, it is expected that it will show great utility as a paving material.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.4
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• pp.1-14
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• 2012

A river is defined as the watercourse flowing through its channel, and the mapping tasks of a river plays an important role for the research on the topographic changes in the riparian zones and the research on the monitoring of flooding in its floodplain. However, the utilization of the ground surveying technologies is not efficient for the mapping tasks of a river due to the irregular surfaces of the riparian zones and the dynamic changes of water level of a river. Recently, the spatial information data sets are widely used for the coastal mapping tasks due to the acquisition of the topographic information without human accessibility. In this research, we tried to extract a river from the RapidEye imagery by using the ISODATA(Iterative Self_Organizing Data Analysis) classification algorithm with the two different parameters(NIR (Near Infra-Red) band and NDVI(Normalized Difference Vegetation Index)). First, the two different images(the NIR band image and the NDVI image) were generated from the RapidEye imagery. Second, the ISODATA algorithm were applied to each image and each river was generated in each image through the post-processing steps. River boundaries were also extracted from each classified image using the Sobel edge detection algorithm. Ground truths determined by the experienced expert are used for the assessment of the accuracy of an each generated river. Statistical results show that the extracted river using the NIR band has higher accuracies than the extracted river using the NDVI.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.3
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• pp.104-115
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• 2014

A levee is defined as an man-made structure protecting the areas from temporary flooding. This paper suggests a methodology for establishing the levee GIS database using the airborne topographic LiDAR(Light Detection and Ranging) data taken in the Nakdong river basins and the WAMIS(WAter Management Information System) information. First, the National Levee Database(NLD) established by the USACE(United States Army Corps Engineers) and the levee information tables established by the WAMIS are compared and analyzed. For extracting the levee information from the LiDAR data, the DSM(Digital Surface Model) is generated from the LiDAR point clouds by using the interpolation method. Then, the slope map is generated by calculating the maximum rates of elevation difference between each pixel of the DSM and its neighboring pixels. The slope classification method is employed to extract the levee component polygons such as the levee crown polygons and the levee slope polygons from the slope map. Then, the levee information database is established by integrating the attributes extracted from the identified levee crown and slope polygons with the information provided by the WAMIS. Finally, this paper discusses the advantages and limitations of the levee GIS database established by only using the LiDAR data and suggests a future work for improving the quality of the database.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.290-297
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• 2014

BACKGROUND: The current study purposed to analyse the dissipation levels of a neonicotinoid insecticide and clothianidin in paddy and upland soils and clarify the effects of soil moisture on degradation and persistence of the insecticide. METHODS AND RESULTS: In order to achieve the research purposes, clothianidin 8% SG was applied to the paddy and upland fields at the rate of 0.024 kg a.i./10a, while the analytical standard was treated at 0.25 mg/kg soil under laboratory conditions. Based on the multiple first-order kinetics, total clothianidin in soils was dissipated with $DT_{50}$ of 6.7-16.1 and 6.9-8.2 days in the paddy and upland fields, respectively, whereas the figures under the laboratory condition became larger showing 56.3 and 19.6 days. CONCLUSION: As affected by soil moisture, some differences in degradative pathways were observed. Flooding of soil caused evidently demethylation and delayed cyclization of a major metabolite, thiazolylmethylguanidine (TMG) and methylaminoimidazole(MAI), compared to the aerobic upland condition. More than 80% and 50% of the parent compound was dissipated by the 24th day after the final application in both soils and, transformation products had constituted most of soil residues after that.

• Korean Journal of Environmental Agriculture
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• v.9 no.1
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• pp.9-13
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• 1990

The dissipation of insecticide fenitrothion(O,O-dimethyl O-4-nitro-m-tolyl phosphorothioate), fungicide IBP(S-benzyl O, O-diisopropyl phosphorothioate), and herbicide butachlor(N-butozymethyl-2-chloro-2', 6'-diethylacetanilide) in flooded soil planted with rice plants was investigated in outdoor pot conditions. The half lives of IBP, butachlor and fenitrothion in the flooding water treated with IBP at 98g, butachlor at 352.8g, and fenitrothion at 100g ai/10a, were 3.6, 1.7 and within 1 day, respectively. The concentration of fenitrothion at 5 days after application was found to be less than 0.0lppm. In the case of IBP and butachlor after 20 days, the concentration was 0.025 and 0.004ppm, respectively. The concentration of fenitrothion, IBP, butachlor in a soil depth of 0-3cm was 0.07, 1.45 and 3.37ppm on the 3rd day after application, and below 0.05, 0.18, 0.39ppm after 7 days, respectively. However, 27 days after application concentration of IBP and butachlor at 0-5cm soil depth resulted in 0.04 and 0.05ppm, respectively. The disappearance of pesticides was remarkably rapid, compared to those in the some soil under the laboratory conditions. Differences in the concentration of IBP in different soil profiles were few, but amounts of butachlor were remarkably higher at 0-2cm soil depth than below 2cm soil depth.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.3
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• pp.225-236
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• 2003

In order to understand the relationship of depositional environment between fluvial and estuarine-embayment in Han River system, including depositional change in main Han River, more than 250 bottom sediment and 70 suspended sediment were analyzed with hydrologic data. Based on the previous data, the study area can be divided into two environment(fluvial and estuarine-embayment) by Singok underwater dam. The gravelly facies occurs in the South and North Han Rivers and sandy and silty facies occupies in the main Han River. Depositional environment of main Han River changed mainly because of limited sediment transport and hydrological condition. In the estuarine-embayment environment, coarse-grained sediments are dominant in tidal channel and of shore whereas fine and poorly sorted sediments are observed in coastal area. During moderate period, relationship between fluvial-estuarine-embayment system is discontinuou s because of flow restriction by artificial construction such as dam and underwater dam, so that each river system characterizes the individual environment. Fluvial and estuarine system is influenced by tide and, thus, transition zone of estuarine- embayment system moves landward. During flooding period, however, each river system is integrated as continuous depositional system by high discharge and, thus, transition zone of fluvial-estuarine-embayment system moves seaward. For further detailed systems about the lower Singok under-water dam, joint research of South-North Korea should be necessary.