• Journal of Korea Water Resources Association
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• v.55 no.4
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• pp.291-300
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• 2022

Artificial disturbance in mountainous areas increases the sensitivity to erosion by exposure of the subsoil with a low loam ratio to the surface. In this study, rainfall simulations were conducted to evaluate the erodibility of sand and loamy sand in the interrill erosion by the rainfall-induced sheet flow. The mean diameters of sand and loamy sand used in the experiment were 0.936 mm and 0.611 mm, respectively, and the organic matter content was 2.0% and 4.2%, respectively. In the experimental plot, the runoff coefficient of overland flow increased 1.16 times in loamy sand rather than sand. Mean sediment yields of loamy sand and sand by sheet erosion were 3.71kg/m²/hr and 1.13kg/m²/hr respectively. The erodibility, the rate of soil erosion for rainfall erosivity factor, was 3.65 times greater in loamy sand than in sand. As the gradient of the steep slope increased from 24° to 28°, the sediment concentration and the erodibility for two soils increased by about 20%. The erodibility factor K of sandy soils for small plots was overestimated compared to the measured erodibility. This means that RUSLE can overestimate the sediment yields by sheet erosion on sandy soils.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.2
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• pp.158-164
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• 1996

This survey was conducted to investigate the distribution of heavy metal contents in medicinal plants and soils. Plant and soil samples were collected at 254 sites(Angelica gigas : 81, Astragalus membranceus : 38, Platycodn glandiflorum : 36, Paeonia albilora : 34, Codonopsis lanoceolata : 32, Ligusticum chuanxiong : 17, Bupleurum falcatum : 16, respectively) over the country, Soil texture, pH values and heavy metal content of soils and medicinal plants were evaluated as major factors. Soil texture classification showed that sandy loam, loam, loamy sand and silt loam were 46.1%, 26.0%, 19.3% and 8.6% of the total, respectively. The contents of O.M, Ex.Ca. Ex.Mg and EC value were higher in loamy(sandy loam, loam and silt loam)soils than in sandy(loamy sand)soils, but available $P_2O_5$ contents of loamy sand soils were higher than those of sandy loam, loam, and silt loam. The contents of Cd, Cu, Pb, Zn and Ni in soil were high in loamy soils, while Cr content was high in loamy silt soils. The contents of Cu and Cr in Angelica gigas were high in loamy soils, and those of Pb in Astragalus membranceus, Paeonia albiflora and Codonopsis lanoceolata were high in sandy loam soils. Correlation coefficients between heavy metal contents in medicinal plants and their soils with soil texture were positively correlated in sandy loam and loam at Cu, loam at Zn, sandy loam, loam and loamy sand at Cr, respectively. Correlation coefficients between pH value of the soils and contents of Cd, Zn and Ni in medicinal plants were negatively correlated, but those of Cd, Pb, Zn and Ni in soils were positively correlated.

• Journal of the Korean Society of International Agriculture
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• v.23 no.5
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• pp.531-536
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• 2011

This study was conducted to investigate the effects of cultural soil textures on growth and quality of Glycyrrhiza uralensis Fischer from 2009 to 2010. The obtained results from this study were summarized as follows; The growth of stem and leaf were superior to one year old G. uralensis, and surface runner and root growth tended to be better in 2 years old G. uralensis. The weight of stem and leaf were heavy in sandy loam, and plant height, branches, stem diameter in sandy clay loam were better than other soil texture. The growth characteristics, such as length, number and weight of surface runner, was better in order of sandy clay loam > sandy loam > loamy sand. The length of main and lateral root was longer in loamy sand soil than other treatments, and the diameter of main and lateral root was more thicker in sandy loam than others. The number of lateral root was higher in the sandy loam than other treatments. The yield of main and lateral root was in order of sandy loam > sandy clay loam > loamy sand soil. Marketable root yield of one year old and two year old G. uralensis were increased 57% and 71% in sandy loam compare to a loamy sand as 204 kg/10 a, respectively. The content of glycyrrhizinic acid was the hightest as 1.62% in sandy clay loam soil in one year old, and as 1.58% in sandy loam soil in two years old of G. uralensis, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.4
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• pp.340-349
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• 1995

Effects of the zeolite particle size on the soil chemical properties and on rice growth was investigated on the pot with the loamy sand (Sadu series) and silty clay loam(Paju series) soils. All the zeolite treatments brought the increase of unhulled grain yield on the both loamy sand and silty clay loam soils. Unhulled grain yield increased with increasing the amount of zeolite applied and with decreasing the amount of particle size of zeolite applied on both soils. Unhulled grain yield increased significantly by 11.1% (22.79g/head) with 2ton/10a of smaller than $106{\mu}m$ size zeolite on the loamy sand soil and on the silty clay loam soil, yield increased by 9.3% (24.98g/head) with 1.5ton/10a of smaller than $106{\mu}m$ size zeolite. CEC, pH and contents of exchangeable cations of the soil after experiment were raised by increasing the amount of zeolite and also by decreasing the particle size of zeolite at both soil. At the heading stage, the zeolite treatments improved the growth of rice plant compared to control. The nutrient contents(T-N, Ca, Mg, K, Na), except phosphorus, in the rice plant grown on the zeolite treated soils were higher than control plot.

• Horticultural Science & Technology
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• v.33 no.2
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• pp.219-226
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• 2015

The objective of this research was to investigate the influence of various root media on the growth of mother and daughter plants during propagation and early yield after transplanting of 'Seolhyang' strawberry. To achieve this, daughter plants were fixed to connected small pots that contained expanded rice-hull (ERH), a strawberry-specialized commercial medium (SSCM), soil mother materials (SMM), or loamy sand (LS). Then, growth of daughter plants in above- and below-ground tissue as well as early yield after transplanting to plastic house soil were investigated. The growth of daughter plants in terms of plant height, leaf area and fresh weight were the highest in the SSCM treatment. Root growth in terms of the amount of primary roots and root dry weight were the highest in the treatments of ERH and SMM and the lowest in that of SSCM, among treatments tested. The ERH treatment also showed the highest values among treatments in root length, surface area and volume when roots with 0 to 0.4 mm in diameter were investigated. The flower bud differentiation of daughter plants began on Sept. 3 in the ERH treatments, earlier than the SMM (Sept. 5) and in SSCM (Sept. 7) treatments. The tissue N contents of daughter plants were in the range of 1.41 to 1.55% in all treatments, and no significant differences were observed among treatments. This indicates that the low moisture retention capacity of ERH and water stress, rather than tissue N contents, promote the flower differentiation of daughter plants. In the evaluation of early yield after transplant, the ERH treatment of showed the highest yield in the period from November to December, reaching 667 g fruit weight per 10 plants. The yields per 10 plants in the other treatments were 581 g in SMM, 475 g in SSCM and 295 g in LS. Above results imply that the various root media have different effects on the growth of daughter plants as well as flower bud differentiation. Therefore, improvement in early yield after transplant can be achieved through selection of proper root medium for daughter plant propagation.

• Journal of agriculture & life science
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• v.46 no.3
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• pp.19-26
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• 2012

The purpose of this study was to provide basic data for the cultivation of Allium victorialis var. platyphyllum in the area covered with forest vegetation. The populations of A. victorialis var. platyphyllum in Ulleungdo were naturally growing in the communities of Fagus japonica var. multinervis, Acer okamotoanum, Pinus parviflora, Tsuga sieboldii, Pinus densiflora, Pinus thunbergii, Tilia amurensis, and Alnus maximowiczii. On average, the study area of A. victorialis var. platyphyllum population was located in the places of 563 m above sea level, and in the slope area of $27.8^{\circ}$. Soil texture of its inhabitation site mainly consisted of sandy soil, sandy loam, loamy sand, and loam. The depth of the organic layer was 6 cm on average, soil pH 5.4, available phosphate content 18.5 ppm, and cation exchange capacity $18.6cmol_c/kg$. The correlation between the site factors and soil factors by CCA analysis showed that the community of beech tree indicated positive correlation with carbon, nitrogen, sand content, and cation exchange capacity.

• Korean Journal of Environmental Agriculture
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• v.19 no.1
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• pp.67-71
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• 2000

This study was conducted to determine the characteristics of continuous culture and soil texture and their effect on growth and yield of platycodon. The continuous cropping year was treated from 2-years old to 8-years old. The continuous cropping year was correlated with root weight $Y=17.246X+0.95(R^2=0.948^{{\ast}{\ast}{\ast}})$ and root disease incidence rate $Y=12.01X-5.74(R^2=0.946^{{\ast}{\ast}{\ast}})$. The T-N, $P_2O_5$ and MgO content of root were yearly decresed and those of injury roots were higher than those of normal roots. The 2-years old platycodon was treated different soil texture(Loamy sand, Sandy loam, Silt loam, Clay loam). The shoot weight 10.38g, root diameter 1.34cm, root height 16.8cm and root weight 5.46g at silt loam were higher than other soil texture.

• Journal of the Korean Society of Urban Environment
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• v.18 no.4
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• pp.455-463
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• 2018

This study was carried out to assess the distribution and pollution level of organic matters and nutrients in surface sediments of the Yeongsan River Basin. The surface sediments were collected from the mainstream (12) and tributaries sites (4) for two years from 2015 to 2016, and the particle sizes, organic matters (Ignition Loss, COD, TOC) and nutrients (TN, TP, SRP) were analyzed. The distribution of particle sizes was dominated by sand in the upstream sites (MS1-MS7) and by silt loam in the downstream sites (MS8-MS12), but MS3 and MS6, located slightly upstream of the two weirs, were found to be mostly loamy sand and silt loam, respectively. As a results of the correlation assessment, the organic matters (IL, COD, TOC) were strongly correlated with particle sizes, while the nutrients (TP, SRP) were weak except for TN. The concentrations of organic matter and nutrient were higher at the downstream and the sites nearby the two weirs (MS3, MS6). In particular, the TP concentration at the MS3 site sampled in the second half period of the years was higher than that in the first half periods. Comparing of sediments criteria, the organic matters and nutrients were evaluated to have almost no toxic effects at all sites.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.4
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• pp.296-304
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• 2022

To maximize the medicinal properties of bellflower root (Platycodi radix), its growth and development according to soil texture were investigated using four types of soil: masato (decomposed granite), soil mix, loamy sand, and sandy loam. Saponin content was measured. With regard to bellflower root growth depending on soil texture, its growth was better in the order of loamy sand > sandy loam > soil mix > masato in the above-ground part, and loamy sand > soil mix > sandy loam > masato in the underground part in the order. The average content of general ingredients were 77.3% water, 2.6% crude fat, 3.2% crude flour, 6.0% crude protein, and 10.9% carbohydrates. With respect to saponin analysis of bellflower roots, the saponin content regarding platycodin D, platycodin D3, polygalacin D, and deapioplatycodin D were higher in the order of 282.4, 104.7, 29.1, 19.1 mg/100 g, respectively. The content of organic matter and phosphoric acid was high in soil mix and sandy loam, and platycodin D3 showed similar levels in all soil types. As a result, the soil mix is considered most suitable in terms of yield and component levels, however, it is the most expensive type. As a replacement, sandy loam was adequate in terms of fresh weight related to yield and highest saponin content.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.3
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• pp.167-170
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• 2000

This study was conducted to investigate the changes of potato growth and soil properties in highland mounding-soil. Experimental plot was designed with control, chemical improvement and zeolite+chemical improvement plots. Mounding-soil was low in organic matter and phosphate contents, and that soil texture was loamy sand soil. The growth and yield of potato were highest in the zeolite treatment plot. Yield of that increased by 3.7% than control plot. Increasing ratios of potato tubers decreased at 60-70 days after planting. Increasing ratio of zeolite plot was higher or than other treatment plots. After harvesting, the contents of soil organic matter increased by 12-125%, and those of phosphate were by 29-73% respectively. The manurial value of fused and superphosphate was higher than that of potassium chloride.