• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.2
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• pp.102-112
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• 2003

This study was carried out to research and develop a shallow green rooftop system which would require low maintenance and therefore could be used for existing rooftops. To achieve these goals, the conceptual model was induced by past studies and the experimental systems were deduced from the conceptual model. On the growth of Sedum sarmentosum grown in these rooftop systems, the effects of artificial substrate type, soil depth, and drainage type were investigated from 3 April to 11 October 2002. Artificial substrates were an alone type and a blending type. The alone type was an artificial substrate formulated by blending crushed porous glass with bark(v/v, 6:4). The blending type was formulated by blending the alone type with loam(v/v, 1:1). Soil depths were 5cm, loom, and 15cm. Drainage types were a reservoir-drainage type and a drainage type. The reservoir-drainage type could keep water and drain excessive water at the same time. The drainage type could drain excessive water but could not keep water. Covering area, total fresh and dry weight, visual quality, and water content per 1g dry matter were measured. All the variables were analyzed by correlation analysis and factor analysis. The results of the study are summarized as follows. The growth increment was higher in the blending type than in the alone type, the highest in loom soil depth and higher in the reservoir-drainage type than in the drainage type. The growth quality was higher in the blending type than in the alone type, the highest in l0cm soil depth, and higher in the drainage type than in the reservoir-drainage type. In consideration of the permissible load on the existing rooftops and the effects of the treatments on the growth increment and quality, the system should adopt the blending type in artificial substrate types, 5~10cm in soil depths, and the drainage type in drainage types. This system will be well-suited to the growth of Sedum sarmentosum, and when the artificial substrate was in field capacity, the weight will be 75~115kg/$m^2$.

• Magazine of the Korean Society of Agricultural Engineers
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• v.9 no.2
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• pp.1296-1300
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• 1967

This study was made through the utilization of heavy soil taken from the experimental plot of heavy soil in Konkuk University, Changan-dong, Sungdong-ku, Seoul. The soil used in the experiment has the following physical characteristics: 1. The soil is very compact, impervious, and unfit for any plant growth, 2. For improvement of the soil, tile drainage practice has been employed, 3. According to the general theory of tile drainage, it is unnatural that the effect of drainage is actually observed in such a soil. The followings are the results of the experiment: 1. Water moved to crosswise when the plotted soil profile was not broke. In this case the upper sloped part was dry while the bottom part was moistned. The upper part of the tile was also moistned. 2. The crosswise movement of water was not observed in the artificially broken plot of subsoil. However, the water flow from the tile was observed for long period as a result of the increase of soil void, seepage, aeration, and water holding capacity. However, the water flow from the tile in the plot of unbroken subsoil was observed only in short period and soon the flow was stopped. 3. the distance between the tile laid in the heavy soil should not exceed 10m for the efficient drainage. 4. When the pF is 2.5 in the subsoil the moisture content was between 23.97% and 28.20%. However, when the water saturated in the subsoil the moisture content was between 34.30% and 22.10%. Accordingly without the higher pF than 2.5 the water can not be absorbed and therefore the drainage can not be occured.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.5
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• pp.63-69
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• 2001

The main purpose of this study is to seek desalinization effect of subsurface drainage system with rice hull packing in Dae-Ho Reclaimed Land. After 4 years installed sub-surface drainage system, distribution of drained water electric conductivity (ECw) was 4.43~12.78 ds/m. The soil profile showed partial development of the soil structure and compaction of subsoils with increased bulk density. The bulk density of the subsoil was 1.42~1.66 g/cm$^3$, which might limit root growth. The soil color changed near the drainage pipe line. Distribution of soil extract solution ECe and SAR as subsurface drainage pipe position and drainage canal distance showed desalinization effect of subsurface drainage system with rice hull packing as widening effective zone of subsurface drainage pipe.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.4
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• pp.11-21
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• 2000

This study was aimed to establish different drainage types of soil media on the plant growing in rooftop. For this study, experiment plots were installed on the roof of Social Science building, Chongju University, from April, 1998 to September, 1999. (1) Sand and sandy loam as base and check soils, (2) vermiculite as a inorganic soil media (3) "humus sawdust" and "burned rice hull" as organic soil media were used by various mixing ratio Zoysia japonica, was selected for the experiment. The results of this study are as follows : L5B3S2 and L5H3S2 of bad drainage character with a plastic drainage plate combination caused good growth effect on Zoysia japonica examined in 3 types of drainage layer with 5 types of soil media. From this result, it could be suggested that combined design of plastic drainage plate with 2 soil types - L5B3S2 and L5H3S2 - be desirable composition for regarding weight load and plant growth.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.3
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• pp.214-220
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• 2007

The effects of soil percolation rate on $CH_4$ and $N_2O$ emissions were investigated from paddy fields with different drainage systems. Subsurface tile drainage plot of soil percolation rate $11.9mm\;d^{-1}$ and non-subsurface drainage plots of soil percolation rate $7.4mm\;d^{-1}$ and $6.9mm\;d^{-1}$ were designed. The effects of rice straw application were measured at each drainage plots. The subsurface tile drainage plot of soil percolation rate $11.9mm\;d^{-1}$ showed the lower emission amount both of $CH_4$ and $N_2O$ among treatments. In the subsurface tile drainage plot of $11.9mm\;d^{-1}$ percolation rate, 46% of $CH_4$ and 33% of $N_2O$ emission amounts were reduced in comparison of non-subsurface drainage plot of $6.9mm\;d^{-1}$ percolation rate. With rice straw application, the $CH_4$ emission amount was 2.1 times to that from no-applied plot, the $N_2O$ emission amount was not affected by rice straw application.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.5
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• pp.369-382
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• 2017

Accurate and optimal water supply to cereal crop is critical in growing stalks and producing maximum yields. Recently, upland crops are cultivated in paddy field soils to reduce overproduced rice in Korea. In order to increase productivity of cereal crops in paddy fields which have poor percolation and drainage properties, it is necessary to fully understand crop response to excessive soil water condition and management of soil drainage system in paddy field. The objectives of this study were to investigate effects of excessive soil water to sesame growth and to quantify stress response using groundwater levels. Two cultivars of sesame were selected to investigate; Gunbak and Areum. These sesames were planted in paddy fields located in Miryang, Gyeongnam with different soil drainage levels and drainage systems. The experiment site was divided into two plots by drainage class; very poorly and somewhat poorly drained. Two different drainage systems were applied to alleviate excessive soil water in each plot: open ditch and pipe drainage system. Soil water contents and groundwater levels were measured every hour during growing season. Pipe drainage system was significantly effective to alleviate wet injury for sesame in paddy fields. Pipe drainage system decreased average soil moisture content and groundwater level during sesame cultivation. This resulted in greater yield and lignan contetns in sesame seeds than ones from open ditch system. Comparison between two cultivars, Gunbak had greater decrease in growth and yield by excessive soil water and high groundwater level than Areum. Seed components (lignan) showed decrease in seeds as soil water increased. When soil moisture content was greater than 40%, lignan content tended to decrease than ones from less soil moisture content. Based on these results, pipe drainage system would be more effective to reduce wet injury to sesame and increase lignan component in paddy field cultivation.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.181-188
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• 2004

Composite soil methods among granular pile merhods that we could improve soft ground of fine soil particles by, have permeability as one of fundamental principals. The catual state, that voids of sand or gravel, etc. of granular soil as drainage materials are clogged by fine soil particles, is 'clogging'. In this study, it is analysed that using sand or gravel, etc. of granular soil as drainage materials, experiment are made by clogging tester on several condition.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.618-627
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• 2015

Soil salinity is the most critical factor for crop production at reclaimed tidal saline soil. Subsurface drainage system is recognized as a powerful tool for the process of desalinization in saline soil. The objective of this study was to investigate the effects of subsurface drainage systems on soil salinity and corn development at Saemangeum reclaimed tidal saline soil. The field experiments were carried out between 2012 and 2014 at Saemangeum reclaimed tidal land, Buan, Korea. Subsurface drainage was installed with four treatments: 1) drain spacing of 5 m, 2) drain spacing 10 m, 3) double layer with drain spacing 5 m and 10 m, and 4) the control without any treatment. The levels of water table showed shorter periods above 60 cm levels with the deeper installation of subsurface drainage system. Water soluble cations were significantly greater than exchangeable forms and soluble Na contents, especially in surface layer, were greatly reduced with the installation of subsurface drainage system. Subsurface drainage system improved biomass yield of corn and withering rate. Thus, the biomass yield of corn was improved and the shoot growth was more affected by salinity than was the root growth. The efficiency of double layer was not significant compared with the drain spacing of 5 m. The economic return to growers at reclaimed tidal saline soil was the greatest by the subsurface drainage system with 5 m drain spacing. Our results demonstrated that the installation of subsurface drainage system with drain space of 5 m spacing would be a best management practice to control soil salinity and corn development at Saemangeum reclaimed tidal saline soil.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.3
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• pp.219-224
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• 1996

Silage comkv, suwwn 19). sorghum $\times$ sudangrass(p. 988) and winter ryeNaton) were cultivated on imperfectly drained paddy field under two different draining methods, subsurface darinage by PVC pipes and open ditsched surface drainage. The crops were harvested at the stage of hard dough for corn and soft dough for wrghum and rye. The soil physical properties. soil colors. soil structure and soil wetness were improved in the subsurface drainage. Gravitational water table occured depth in 110 cm(dry season)~75cm(rain season). In soil profile description, yellowish brown with yellowish red mottles and well developed granular structure were found in the surface A horizon. The portion of solid phase in subsoils(B horizon) was reduced from 48.6%(undrained) to 43.7 %. A blocky structure with dark gray to gray were described in the open ditsched surface drainage. Severe wet depression of the crops was observed due to it's higher moisture contents, where the gravitational water occured depth in 25~37cm during the rainy season. The chemical properties of paddy soils were less affected by drainage methods. The concentration of available phosphate. organic matter and exchangeable K, Ca and Mg were decreased in the subsurface drained soils. The annual dry matter yields of com-rye cropping were 17.8 ton in the undrained, 21.6 ton in the open ditsch drainage and 35.9 ton/ha in the subsurface drainage.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.966-972
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• 2009

Soil-aggregate system in pavement foundations exist in unsaturated conditions. However, change in water content on foundation layers due to joint and structural cracks during rainfall may cause problems like layer deformations or partial settlements. Therefore, a need exist to evaluate the infiltration and drainage capacity of soil-aggregate foundation system under both saturated and unsaturated conditions. To do that, a laboratory soil-water characteristic curve and permeability under unsaturated conditions are assessed to establish hydraulic properties of geomaterials and limited numerical analysis are performed respectively. As a result, it was found that suction profiles and drainage process was greatly influenced by the initial suction of soil-aggregate system at the time of infiltration, soil water characteristics curves, and hysteresis effects.