• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.6
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• pp.77-84
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• 2004

This study was carried out to analyze the vertical and horizontal distribution of fine root biomass of Pinus thunbergii transplanted in reclaimed land from the sea near Gwangyang Bay. The fine-root biomass according to 6 planting ground types were as follows: 98.5 g DM/$m^2$ for P2, 51.1 g DM/$m^2$ for P6, 47.8 g DM$m^2$ for P5, 44.6 g DM/$m^2$ for P3, 38.2 g DM/$m^2$ for P4, 31.8 g DM/$m^2$ for Pl, respectively. The vertical distribution of fine root biomass decreased at descending soil depths of the 6 mounding types. Fine root biomass was 31∼55% in the topsoil of 20cm depth. Fine root biomass that were related to the Spatial distance from the nearest tree were unevenly distributed horizontally in 6 stands. distribution patterns of fine root biomass were closely related to soil hardness and alkalic cation (Ca++, Mg++, Na+, K+) concentrations. Therefore, in order to have good condition for the growth of landscaping plants, we suggest that there is a need for the construction of planting grounds as well as a need for soil improvement in bad soil environments.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.6
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• pp.85-94
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• 2004

This study was carried out to analyze physicochemical properties according to the soil height and to the six types of sites that were used as planting ground in the reclaimed land from the sea, Gwangyang Bay. The physicochemical properties of the soil types were tested by t-test(p<0.01, 0.05), at each of the 6 planting ground sites(p<0.01, 0.05), and at each height(p<0.01) of the planting grounds. These areas were tested by ANOVA and were significantly different. Improved soil was better than reclaimed soil from the sea for Zelkova growth because the improved soil contained lower amounts of pH, ECe, N $a^{+}$, $Ca^{++}$, $Mg^{++}$ SAR. Due to freedom from variables such as salt content in the underground as well as the physical and chemical disturbance of the soil, favorable planting ground for tree growth was recorded at the higher grounds than at the lower ones. Soil detriment to the tree growth in the studied sites included elements such as soil hardness, and the distribution of sodium in the tree root systems. The planting grounds for the favorable growth of landscape trees were determined in the following order: the grounds of mounding> the coved ground of improved soil, and the filled ground of improved soil.l.l.l.

• Earthquakes and Structures
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• v.12 no.4
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• pp.457-468
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• 2017

When studying the vibration of a suspension bridge based on the traffic-bridge coupled system, most researchers ignored the contribution of the pavement response. For example, the pavement was simplified as a rigid base and the deformation of pavement was ignored. However, the action of deck pavement on the vibration of vehicles or bridges should not be neglected. This study is mainly focused on establishing a new methodology fully considering the effects of bridge deck pavement, probabilistic traffic flows, and varied road roughness conditions. The bridge deck pavement was modeled as a boundless Euler-Bernoulli beam supported on the Kelvin model; the typical traffic flows were simulated by the improved Cellular Automaton (CA) traffic flow model; and the traffic-pavement-bridge coupled equations were established by combining the equations of motion of the vehicles, pavement, and bridge using the displacement and interaction force relationship at the contact locations. The numerical studies show that the proposed method can more rationally simulate the effect of the pavement on the vibrations of bridge and vehicles.

• Advances in nano research
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• v.15 no.6
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• pp.533-539
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• 2023

This study aims to examine four machine learning (ML)-based models for their potential to estimate the splitting tensile strength (STS) of manufactured sand concrete (MSC). The ML models were trained and tested based on 310 experimental data points. Stone nanopowder content (SNPC), curing age (CA), and water-to-cement (W/C) ratio were also studied for their impacts on the STS of MSC. According to the results, the support vector regression (SVR) model had the highest correlation with experimental data. Still, all of the optimized ML models showed promise in estimating the STS of MSC. Both ML and laboratory results showed that MSC with 10% SNPC improved the STS of MSC.

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.369-376
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• 2006

This research was conducted to evaluate the effect of root medium formulations on growth and nutrient uptake of hot pepper 'Knockgwang' in 72-cell plug trays. To achieve this, the nine root media were formulated by adjusting blending rate of perlite (PL) to coir (CO), peatmoss (PM) or coir+peatmoss (5:5, v/v, COPM). Then, the growth characteristics and tissue nutrient contents were determined at 35 and 70 days after sowing. The elevated blending rate of PL to CO increased fresh and dry weight of hot pepper at 35 days after sowing. The treatments of 20% in blending rate of PL to PM or that of 0% to COPM produced the highest fresh and dry weight among perlite treatments of PM or COPM. The results of crop growth at 70 days after sowing also showed similar trends to those of 35 days after sowing. The elevated blending rate of PL to CO or PM decreased tissue $P_2O_5$ and K contents and increased Ca and Mg contents at 35 days after sowing, With the equal blending rate of perlite, the plant tissue grown in CO had higher K contents and lower N, Ca and Mg contents than those in PM and COPM. The elevated blending rate of perlite in three organic matter also decreased tissue $P_2O_5$ and K contents at 70 days after sowing, but Ca and Mg contents were the highest in the treatment of 20% PL in CO, 40% PL in PM and 40% PL in COPM among perlite treatments in each organic matter.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.379-387
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• 2007

This research was conducted to evaluate the influence of pre-planting fertilizer levels (PFL) and initiation time of fertigation (ITF) on growth and nutrient contents of tomato plug seedlings. The pre-planting fertilizer levels in a coir+peatmoss+perlite (4:4:2, v/v/v) substrate were adjusted to 0.5X, 1.0X and 1.0X, and initiation time of fertigation was set to 7, 14,21 and 28 days after sowing. Elevated PFL in same ITF increased plant growth such as fresh and dry weights at 35 and 70 days after sowing. Plugs with early feeding among treatments of equal amount of PFL also showed better growth as compared to those of later feeding. In each ITF, 0.5X treatment had the higher tissue $P_2O_5$ contents than 1.0X and 1.5X treatments. Elevated PFL resulted in the decrease of tissue K, Mg and Fe contents and increase of tissue Ca contents. The pH in soil solution of all root substrates except 0.5X treatment at 35 and 70 days after sowing were greater than 7.0, which is too high. This suggests that the amounts and kinds of Ca containing fertilizers should be altered to decrease the pH. The results of this research indicated that fertilizer levels should be increased to 1.5X except Ca fertilizer, and fertigation immediately after moving plug trays from germination room to greenhouse is required to increase crop growth and decrease cropping time.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.2
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• pp.164-170
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• 2005

The amounts and nutrient compositions in precipitation, throughfall, stemflow and soil solution of natural deciduous forests (Quercus variabilis and Q. mongolica) were examined in Gwangju, Gyeonggi Province. The proportion to gross precipitation was $85\%$ for throughfall, $2-6\%$ for stem flow, $53-54\%$ for Ao horizon soil solution, $23-30\%$ for A horizon soil solution, and $11-14\%$$ for B horizon soil solution, respectively. pH and K concentration increased in throughfall and only K concentration increased in stemflow. Canopy leaching appeared to influence these changes. pH, and Ca and Mg concentrations increased significantly in the Ao horizon soil solution, and Ca concentration was higher in the B horizon than in the A horizon. However, there were no significant differences in pH and other nutrient concentrations between A and B horizons. Litter decomposition and leaching from Ao horizon might explain the changes. K, Mg and Cl concentrations in throughfall and soil solution decreased with precipitation. Nutrient contents increased in the transports from precipitation, through throughfall, to Ao horizon soil solution, while they decreased in the transport from A to B horizon soil solution. Stemflow contained less than $10\%$ of total (throughfall plus stemflow) nutrient contents.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.4
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• pp.64-71
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• 2009

Excessive soil organic matter (SOM) is detrimental to turfgrass quality when used intensively in sand-based root zones, thereby affecting the sustainability of turfgrass systems. As part of a major project examining the sustainable management of SOM on golf greens, microbial decomposition on soil organic matter accumulation with depth was assessed and the effect of soil air-condition improvement and Ca fertilization was investigated by soil microbial respiration (SMR). Three soil samples from three depths(0~5, 5~10, and 10~15cm) of 5 year and 30 year old green were analyzed for SOM content. In 30 year old green, SMR and dehydrogenase activity(DHA) were analyzed to assess the soil microbial decomposition with depth. It was then divided into 4 plots: untreated as a control, dolomite-treated, 0~5cm deep section-removed, and 0~5 cm deep section-removed+dolomite-treated. After treatment, three soil samples were taken at 1, 2 and 4 weeks by the above-mentioned method, and analyzed for SMR to better understand SOM decomposition. SOM accumulation in the 0~5cm depth of golf greens can be controlled by intensive cultivation such as coring, but below 5cm is more difficult as the results showed that SOM content below 5cm increased over time. Soil microbial decomposition of organic matter will be necessary to reduce SOM accumulation, but SMR below 5cm was low and wasn't significantly altered by increasing exposure to air and fertilizing with Ca. As a result, aeration treatments such as coring and Ca fertilization might not be effective at improving soil microbial decomposition below 5cm depth in aged greens.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.2 s.109
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• pp.60-70
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• 2005

This study was carried out to elucidate the vertical characteristics of soil properties at six planted sites of land reclaimed from the sea, in Gwangyang Bay, Jeollanam-do Province, Korea. Based on the types of planting site, the chemical properties of the vertical soil layers varied. The vertical variation was great in the planting sites $Z_1\;and\;Z_2$, but less varied in the mounded planting sites $Z_3,\;Z_5,\;and\;Z_6$. Major reasons for the vertical variation in soil chemical properties included differences in the accumulation of organic matter, soil disturbance by heavy construction equipment, and heterogeneity of soil properties between soil horizons. As soil depths increased, soil salts varied. The electrical conductivity (ECe) increased in the lower areas of planting sites $Z_1\;and\;Z_2$, and the disturbed, saline planting site $Z_3$, but decreased in the lower areas of $Z_3,\;Z_5,\;and\;Z_6$. These tendencies did not coincided with exchange cation concentrations $(Na^+,\;K^+,\;Mg^{++},\;Ca^{++})$. Both total carbon (T-C) and total nitrogen (T-N) accumulated more in the lower areas of planting sites than in the higher areas, and levels were higher closer to the surface than in the soil depths. It is supposed that these tendencies are related to the accumulation of fallen leaves or other organic matter at the soil surface, and the soil chemicals then slowly move downward from the surface. Impediments to tree growth included soil hardiness, high soil salinity and exchangeable cation concentration, low soil moisture content, acidic or alkaline soil, low organic matter, heterogeneity of soil texture and establishment of soil stratification.

• Weed & Turfgrass Science
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• v.2 no.1
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• pp.82-87
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• 2013

This research will be utilized as a base line data by researching on growth and the accumulation of inorganic nutrients during the cultivation period of zoysiagrass and also to establish a cultivation strategy of zoysiagrass. It involves the management such as fertilizer and mowing which ultimately led to the difference of growth and accumulation of inorganic nutrients. The accumulation of inorganic nutrients after mowing, the amount of accumulation was small when compared to the amount lost for the shoot, rhizome and root. Difference in the accumulation of inorganic nutrients, but as for K, Ca and Mg accumulation it shows similar aspects to N accumulation. The orders of inorganic nutrients in zoysiagrass were N > K > P > Ca > Mg. The characteristics of inorganic nutrients absorption of such zoysiagrass acts as the foundation of cultivation, and in the aspect of making decisions on the fertilization amount and soil management, it is closely related to the requirement on nutrients. In order to increase the productivity based on the zoysiagrass's growth and density rate improvement, accumulation of inorganic nutrients per growth period needs to be analyzed, and supplying nutrients in an efficient method suitable to the growth period is advisable, so such basic research was necessary.