• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.79-88
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• 2011

The purpose of this study was to obtain information on rates and salinity levels of irrigation for growth of Kentucky bluegrass by minimizing the hazard of salt accumulation in the sand based growing medium. Root zone profile consists of 20 cm sand based top soil, 20 cm of coarse sand as layer to interrupt capillary rise and 10 cm of reclaimed paddy soil as a base of the root zone profile. Topsoil was a mixture of dredged sand and peat with a ratio of 95%: 5% by volume. The columns were soaked into 5 cm depth saline water reservoir with salinity level of 3-5 $dSm^{-1}$. Salinity levels of irrigation water were 0, 2 and 3 $dSm^{-1}$. Irrigation rates were 3.8, 5.7 and 7.6 mm $day^{-1}$ which were equivalent to 70%, 100% and 130% of average ET (evapotranspiration) rate of Kentucky bluegrass, and irrigation interval was 3 days. Salt accumulation was due to irrigated water and moved up water from shallow water base. At the end of second year, the accumulation of salt in the rootzone showed ECc of3.86, 4.7 and 5.1 $dSm^{-1}$, and SAR of 19.2, 23.9 and 27.5 when the salinities were 0, 2 and 3 dS $m^{-1}$, respectively. Irrigation rates of 100% and 130% of ET rate with saline water did not decrease ECe and SAR in growing media. The growth of KEG was influenced by irrigation rate in the $1^{st}$ year, however, salinity level was more critical in the $2^{nd}$ year. Compared to non-saline water, saline water of 2 and 3 dS $m^{-1}$ resulted in decreased visual quality by 3.2% and 16.5%, by 6.4% and 39.3% in clipping weight, and by 5.5% and 5.0% in root mass, respectively.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.208-216
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• 2011

The purpose of this study was to find soil-amendment materials those support the growth of Kentucky bluegrass and reduce salt accumulation at the sand based growing media in saline conditions. Rootzone profile in columns consisted of 20 cm of top soil, 20 cm coarse sand as capillary rise interruption layer and 10 cm reclaimed paddy soil as the base of the profile. Top soils were mixtures of dredged sand (DS) and amendment with compositions of 90% sand + 10% peat moss (SP), 80% sand + 10% soil + 10% bottom ash (SSoBa), 80% sand + 20% soil (SSo), 90% sand + 5% peat + 5% zeolite (SPZ), and 80% sand + 20% bottom ash (SBa). The top soil mixtures of DS and amendments were treated with and without gypsum (Gp). The columns were soaked into 5 cm depth saline water reservoir with the salinity level of $3-5dSm^{-1}$. Irrigation of $2dSm^{-1}$ saline water with rate of $5.7mm\;day^{-1}$ was applied by 3 day interval. Application of zeolite decreased SAR, application of gypsum decreased ECe of the sand amended by peat + zeolite and decreased the SAR of sand amended by bottom ash. The SP and SSoGp resulted in higher clipping dry weight of Kentucky bluegrass. The SSoGp and SPZGp showed longer root lengths. The SP and SBaGp showed higher visual quality. Addition of gypsum to soil and bottom ash treatments resulted in the increased shoot growth, whereas additional gypsum to the treatments of peat, soil and zeolite increased the root growth of Kentucky bluegrass.

• Radiation Oncology Journal
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• v.21 no.2
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• pp.167-173
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• 2003

Purpose: The purpose of this study was to evaluate whether a GafChromic film applied to stereotactic radiosurgery with a linear accelerator could provide information on the value for acceptance testing and quality control on the absolute dose and relative dose measurements and/or calculation of treatment planning system. Materials and methods: A spherical acrylic phantom, simulating a patient's head, was constructed from three points. The absolute and relative dose distributions could be measured by inserting a GafChromic film into the phantom. We tested the use of a calibrated GafChromic film (MD-55-2, Nuclear Associate, USA) for measuring the optical density. These measurements were achieved by irradiating the films with a dose of 0-112 Gy employing 6 MV photon. To verify the accuracy of the prescribed dose delivery to a target isocenter using a five arc beams (irradiated in 3 Gy per one beam) setup, calculated by the Linapel planning system the absolute dose and relative dose distribution using a GafChromic film were measured. All the irradiated films were digitized with a Lumiscan 75 laser digitizer and processed with the RIT113 film dosimetry system. Results: We verified the linearity of the Optical Density of a MD-55-2 GafChromic film, and measured the depth dose profile of the beam. The absolute dose delivered to the target was close to the prescribed dose of Linapel within an accuracy for the GafChromic film dosimetry (of $\pm$3$\%$), with a measurement uncertainty of $\pm$1 mm for the 50$\~$90$\%$ isodose lines. Conclusion: Our results have shown that the absolute dose and relative dose distribution curves obtained from a GafChromic film can provide information on the value for acceptance. To conclude the GafChromic flim is a convenient and useful dosimetry tool for linac based radiosurgery.

• Proceedings of the Turfgrass Society of Korea Conference
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• 2011.02a
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• pp.5-8
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• 2011

This research was conducted to determine the effect of capillary rise interruption layer on the sand based growing media when growing Kentucky bluegrass under soil reclamation and saline water irrigation. Rootzone profile consists of three layers as top soil of 30 cm, 20 cm of capillary interruption layer and 10 cm of reclaimed paddy soil. Rootzone profile was packed in column pots. The top soil was a mixture of sand dredged up from Lake Bhunam Tae Ahn, Korea and peat at the ratio of 95:5 by volume. Bottom part of column was covered with plastic net and the pots were soaked into 5 cm depth saline water reservoir with salinity $3-5dsm^{-1}$. Kentucky bluegrass was installed by sod and irrigated using $2dSm^{-1}$ saline water(5.7mm $day^{-1}$)in 3days interval. The results showed that the largest accumulation of salt in the spring with ECe of $5.4dSm^{-1}$ and SAR34.0 in rootzone with out capillary rise interruption layer and ECe of $4.6dSm^{-1}$ and SAR8.24 at rootzone using gravel as capillary rise interruption layer material. Kentucky bluegrass grown in growing media with gravel as capillary rise interruption layer resulted in the average visual quality rate of 8.1and clipping dry weight of $24.8gm^{-2}$, while Kentucky bluegrass grown in the growing media with out capillary rise interruption layer showed the visual quality rate of 7.9 and clipping dry weight of $34g.m^{-2}$. Capillary rise interruption layer of gravel and coarses and enhanced the visual quality by 4.1and 4.0%, root length by 50 and 38%, and root dryweight by 35and 17% of Kentucky bluegrass, and reduced the accumulation of Na by 16% and 25%, ECe by 7% and 13% in the rootzone.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.2
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• pp.75-81
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• 1973

The morphological, physical, and chemical properties of Sonjeong series derived from acidic crystalline rocks are presented. Also it deals with the genesis and classification of the Songjeong series. Morphologically these soils have brown to dark brown loam A horizons and yellowish red to red clay loam Bt horizons with moderate, medium subangular blocky structure and thin patchy clay cutans on the ped faces. C horizons are very deep, yellowish red to yellowish brown fine sandy loam or sandy loam with original rock structure. Physically distribution of particle size indicates that clay increases with depth up to argillic horizons but below the argillic horizons clay content decrease. The moisture holding capacity is fairly good in Songjeong soils. Chemically soil reaction is strongly to very strongly acid throughout the profile and content of organic matter is less than 1 per cent except A horizons. Cation exchange capacity ranges from 5 to 9 me/100g of soils and base saturation is less than 35 per cent throughout the profile. The natural fertility of Songjeong soils are usually low. It needs lime, organic matter, and heavy application of fertilizer for the crop land. These soils occur temperate and humid climate under coniferous, deciduous, and mixed forest vegetation. Songjeong soils are classified as Red-Yellow Soils. Characteristically Songjeong soils are similar to Red-Yellow Podzolic soils in the United States but lack of A2 horizons and are quite liket Red-Yellow Soils of the Japan. According to new classification system which is 7th approximation of USDA Songjeong soils can be classified as fine loamy, mesic family of Typic Hapludults and in the FAO/UNESCO project World Soil Map as Orthic Acrisols.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.2
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• pp.135-144
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• 1995

Understanding on nutrient solute movement during the course of freezing and thawing was attempted through laboratory and field obsevations. Small sectioned tubes with 5cm inner diameter, 0.2cm thick and 1cm long were connected to 30cm long soil columns for laboratory study. The columns were filled with soil, and treated with 20mmol/kg $KNO_3$ for upper 5cm. The upper end was set in the freezing section, and the lower end was set in the refrigerating section of a refrigerator. Temperature was controlled at $-7({\pm}1)^{\circ}C$ and $1.5({\pm}1)^{\circ}C$, respectively. After top 5cm soil was frozen, the columns were sectioned, and analyzed for $NO_3^-$, $NH_4^+$ and $K^+$. For field study, the 20cm inner diameter and lm long soil columns were installed in Chuncheon and Daegwanryung, where the altitude was 74m and 840m, respectively. The soils used were silt loam and clay loam. The top 20cm soils were treated with 50mmol/kg as $KNO_3$. The soil columns were taken during winter freezing and after thawing. By laboratiry study, upward movement of $NO_3^-$ and $K^+$ during the course of freezing was confirmed. The upward movement of $K^+$ was, however, one fifth to one tenth of $NO_3^-$. The upward movement of inorganic nitrogen as well as laboratory during the course of freezing, but large amount of nitrogen was lost from the profile after thawing in early spring. Leached nitrogen from the upper 20cm to lower part was 17 to 24 percents. The maximum depth of leaching during the experiment was 50cm for all soils. The net loss of inorganic nitrogen from the whole profile ranged 8.7 to 39.5 percents. The net loss was greater in Daegwanryung where temperature was lower and snowfall was larger than Chuncheon, and the loss was greater from the silt loam soil than clay loam soil of which percolation rate was small. The results implied that reasons for nitrogen loss during the winter might include surface washing by snow melt as well as leaching and denitrification.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.2
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• pp.127-135
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• 2002

This study was conducted to investigate the physico-chemical and microbiological properties in profile depth during composting process with different turning times when pig manure was composted with ground rice hulls at the rate of same for the promotion of the composting. The moisture contents, C/N rate and pH value decreased according to composting progresses as run into turning times, but increased those inside layer of the pile. $NH_4-N$ and $NO_3-N$ contents were high in the outer layer mostly, as the result the $NH_3$ flux was high in there, but it decreased as composting progresses. The number of aerobic bacteria were $10^7{\sim}10^9\;cfu\;g^{-1}$, increased as the turning times, the number of their showed high in the outer layer. The number of fungi were $10^2{\sim}10^4\;cfu\;g^{-1}$ at the early period of composting, but did't almost survive inside layer as composting progresses. The number of cellulose decomposer and thermophilic bacteria were $10^6{\sim}10^7\;cfu\;g^{-1}$ and $10^6{\sim}10^9\;cfu\;g^{-1}$, respectively, they showed high inside layer of the pile. Therefore, the turning of composting can reduce the change difference of microorganisms in the pile. Turning frequence for the promotion of composting showed approximately 2~3 times.

• Korean Journal of Weed Science
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• v.17 no.3
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• pp.269-280
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• 1997

Collated data from the 1995-1996 field surveys of weed seeds buried in the plough layer of peat soil in Selangor district were analysed to assess species-dominance and spatial pattern of distribution of weed seeds based on selected quantitative indices and index of dispersion. Forty five species within 14 families were recorded of which 24 were broadleaves, 12 grasses and 9 sedges. They comprised ca. 53.2, 31.2 and 15.6%, respectively based on total population counts. Total seed population was ca. $8.14{\times}10^7$ seeds/ha within the fast 25cm soil depth. Wide variabilities in population counts were registered among species ranging from < $7.0{\times}10^4$ seeds/ha for Amaranthus gracilis to ca. $5.64{\times}10^6$ seeds/ha for Heteropogon contortus. Seeds of Cleome rutidesperma was the most abundant(ca. $2.347{\times}10^7$ seeds/ha). Difference in seed population counts may be attributed to inherent variation in fecundity, population fluxes, their spatial distribution patterns and the agronomic practices prevailing in the areas of survey. The profile distribution of soil seed banks was skewed within the first 0 - 10cm depth, comprising ca. 69% of the total seed counts. Seed counts in the 10 - 15, 15 - 20 and 20 - 25cm soil profiles were in the order of 17.9, 8.6 and 4.0% of the total populations, respectively. Weed seeds of all species displayed different degree of aggregated pattern of distribution with variance-to-mean ratios of > 1 and Lloyd's mean crowding($m^*$) values from 1.244 for Cyperus iria, Phyllanthus debilis, Phyllanthus urinaria, Scirpus grosses and urinaria lagopodiodes to 9607.7 for Cleome rutidosperma. Lloyd's patch indices(Ip) ranging from 5.1 for Aeschynomene indica to 188.5 for Bracharia reptans were registered. Differences in the VMR, $m^*$ and Ip values among species suggested inter-alia inherent variabilities in their disposal capacity from seed source and different agronomic practices prevailing in the areas surveyed.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.2
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• pp.131-146
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• 2014

High-resolution seismic profiles coupled with sediment sampling were analyzed to investigate the acoustic characters and distribution patterns of the late Holocene sediments in Gamak Bay of the South Sea, Korea. The mean grain size of surficial sediment lies around $6.3{\sim}9.7{\Phi}$. Sediments in the bay consist of silt and clay with progressive decrease toward the inner bay. The seismic sedimentary sequence overlying the acoustic basement can be divided into two sedimentary units (GB I and II) by a prominent mid-reflector (Maximum Flooding Surface; MFS). The acoustic basement occurs at the depth between 20 m and 40 m below the sea-level and deepens gradually southward. The GB I, mostly occupying the channel-fill, is characterized by reflection-free seismic facies. It can be formed as late Transgressive System Tract (TST), interpreted tidal environment deposits. MFS appears at the depth of about 15~28 m below the sea-level and is well defined by even and continuous reflectors on the seismic profile. The GB II overlying MFS is composed of acoustically transparent to semitransparent and parallel internal reflectors. GB II is interpreted as the Highstand System Tract (HST) probably deposited during the last 6,000 yrs when the sea level was close to the present level. Especially, it is though that the GB II was subdivided into two layers (GB II-a and II-b) by a HST-reflector and this was classified by wind, sea water flux, and tidal current.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.4
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• pp.213-220
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• 1982

Soil water changes in lysimeters with four different soils and two different available soil depths were monitored during the growing seasons of the soybean-barley cropping from 1977 to 1980 in Suweon to evaluate evapotranspiration (ET) as a function of available soil water and evaporative demand of the atmosphere. ET was calculated with soil water profile and water balance. Soil water content was measured with a neutron moisture depth gauage and The evaporative demand of the atmosphere was estimated with a class A pan evaporation. Rainfall. solar radiation, and wind speed were observed to examine heat and water balances. The average ET of soybeans ranged from 1.6 mm/day at seedling to 6.5 mm/day at flowering, and that of barley ranged from 0.5 mm/day at the regrowth stage to 4.6 mm/day at heading; however, a large variability was observed. The ratio of ET to pan evaporation ($ET/E_o$) ranged from 0.5 to 1.1 for soybeans and 0.4 to 1.2 for barley. The soil evaporation factor ($K_e$) of the $ET/E_o$ component decreased as the soil water depleted and the canopy developed. The crop transpiration factor ($K_t$), another component of $ET/E_o$, also was a function of time and the soil water. $K_t$ was constant when the available soil water fraction (f) in the root zone was greater than a threshold value, and $K_e$ was decreased linearly when f was lower than this threshold. The threshold was 0.7 for the moderate evaporative demand days, 0.4 to 0.5 for the low evaporative demand days, and 0.9 to 0.96 for the high evaporative demand days. Conclusively, the ET can be estimated from the evaporative demand of the atmosphere, $E_o$, $K_e$ and $K_t$, and the available soil water content in the root zone.