• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.1
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• pp.20-28
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• 1999

Nine soil media when placed over a plastic sheet with three seeding rates were evaluated for influence on covering rate, height, growth, surface hardness, tear strength and sod establishment of Kentucky bluegrass. 1. Bark, peat and vermiculite over a plastic sheet had good effect in terms of the establishment of Kentucky bluegrass sod. 2. The good establishment of Kentucky bluegrass sod grown on bark, peat and vermiculite over a plastic sheet seemed to be caused by physical and chemical properties of each soil medium. 3. Sand, sandy loam, perlite and peatmoss caused poor effects on the covering rate, the growth, and the tear strength of Kentucky bluegrass. 4. Optimum seeding rate was $10g/m^2$ in terms of density and competition. 5. Good quality sod more depended on soil media than on seeding rates in this study.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.278-284
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• 2016

Commercial Korean domestic and foreign intermediate food materials (IFMs) of blueberry, Aronia, oat, sweet pumpkin, and ginger were purchased to compare their functional properties, including total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC), and antioxidant capacity. Each IFM was extracted using 80% (v/v) methanol for the analyses. The TPC (mg gallic acid equivalent/100 g dried sample) and TFC (mg catechin equivalent/100 g dried sample) levels in domestic blueberry (TPC, 2,916 ± 200; TFC, 1,327 ± 31) and sweet pumpkin (TPC, 476 ± 20; TFC, 23 ± 32) IFMs were significantly higher than those in the foreign IFMs. In the case of TAC (mg cyanidin-3-glucoside/100 g dried sample), the level in domestic blueberry IFM (949 ± 57) was significantly higher than that in the foreign product. Among the domestic IFMs, the antioxidant capacities (mg vitamin C equivalent/100 g dried sample) of blueberry, sweet pumpkin, and ginger were 7,057 ± 321, 311 ± 8, and 3,321 ± 109, respectively, being significantly higher than those of their foreign counterparts, based on the ABTS radical scavenging assay. In the DPPH radical scavenging assay, foreign Aronia (12,667 ± 437) and ginger (2,067 ± 99) IFMs showed significantly higher levels of free radical scavenging activity than did the domestic IFMs. These results provide basic information regarding the functional properties of Korean domestic IFMs, compared with their foreign counterparts.

• Asian Journal of Turfgrass Science
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• v.24 no.2
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• pp.145-148
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• 2010

Nitrogen (N) is one of the most important nutrients among 17 essential nutrients for maintaining turfgrass color and quality. The slow release fertilizers were initially developed to provide a more consistent release of nitrogen over a longer period and are often used to decrease leaching potential from sandy soils. The goal of this study is to determine if various slow release N sources affect the rate at which turfgrass establishes. Six nitrogen sources were evaluated; Nitroform (38-0-0), Nutralene (40-0-0), Organiform (30-0-0), Sulfur coated urea (SCU, 37-0-0), urea (46-0- 0), and Milorganite (6-0-0). The root zone media was seeded and sodded with 'Limousine' Kentucky bluegrass (Poa pratensis L.). Sodded pots produced 182 to 518 g more clipping dry weight than seeded pots. Among seeded pots, Milorganite produced greater amount of root dry weight than any other N sources. Because the period of turfgrass growth is different between sodded and seeded plots, there were differences on clipping yield and root growth. Overall, high N rate had turf color greater than acceptable color of 6 among seeded pots throughout the study. However, low N rate didn't produce acceptable turf color throughout the study. Based on the result of this tudy, ilorganite would be ecommended for new establishment of Kentucky bluegrass an urea with less clipping yield which can lead to reduce abor.

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.73-78
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• 2011

This study was conducted to evaluate the effect of developed SCB (DSCB) liquid fertilizer produced by adding N, P and K at SCB liquid fertilizer on the growth of kentucky bluegrass. Two different N sources used in DSCB were ammonium sulfate (DSCB-A) and urea (DSCB-U), respectively. Fertilizer treatments were designed as follows; non-fertilizer (NF), control (CF; chemical fertilizer), DSCB-A1 ($200\;ml{\cdot}m^{-2}$DSCB-A), OSCB-A2 ($250\;ml{\cdot}m^{-2}$DSCB-A), OSCB-U ($250\;ml{\cdot}m^{-2}$DSCB-U) and CF+SCB (CF+$250\;ml{\cdot}m^{-2}$SCB). Every treatment was arranged in a randomized complete block design with three replications. In kentucky bluegrass, turf color index, chlorophyll index, dry weight and nutrient contents were measured. Results were as follows; It was hardly affected by DSCB and SCB application in investigation of chemical properties of soil. Turf color index and chlorophyll index in DSCB and SCB treatments were increased by 1~2% and 19~24% than NF, respectively and similar to CF. As applied with DSCB and SCB, dry weight of DSCB-U and CF+SCB was increased by 36% and 10% than CF, respectively, but similar to that of OSCB-A1 and DSCB-A2. Evaluated with turf quality and growth, DSCB-U was the best in all treatment and OSCB-A1 the most efficient. These results indicated that applications of OSCB and SCB promoted turf quality and growth of kentucky bluegrass or similar to CF, so that they were expected to replace chemical fertilizers.

• Journal of the Korea Concrete Institute
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• v.25 no.3
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• pp.347-354
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• 2013

Recently, crushed fine aggregates are being widely used due to the shortage of natural sand. In Korea, the amount of fine particles under 0.08 mm contained in crushed fine aggregates is restricted to be less than 7%, which is similar to the regulations of ASTM but is still very strict compared to the regulations of the other nations. In addition, the crushed aggregates already have in them about 20% of fine particles under 0.08 mm which occurs while they are crushed. The fine particles are not easy to wash out, and also to maximize the use of resources it is deemed necessary to review the possibility of enhancing the limit of the amount of fine particles. Therefore, this study conducted experiments to analyze the characteristics of fine particles under 0.08mm and their influence on the properties of concrete. Experiments using silt and cohesive soil were also done for comparison. In the experiments on fine particles, the methylene blue value was more in the soil dust contained in silt and cohesive soil than in the stone powder contained in crushed fine aggregates. Also, the methylene blue value had a close correlation with packing density and liquid & plastic limit. In the experiments done with concrete, the quantity of high range water reducing agent demanded to obtain the same slump increased as the fine particle substitution rate heightened. However, in the experiment which used stone powder testing the compressive strength and tensile strength of concrete in the same water-cement ratio, there was little change in strength with less than 20% addition of fine particles among the fine aggregates, and no meaningful difference in the amount of drying shrinkage of concrete.

• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.31-38
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• 2014

Rooting agents and shading treatments were tested in two different experiments to determine their effects on the establishment success of hardwood cuttings of three highbush blueberry varieties 'Bluecrop', 'Duke' and 'Sunrise'. For the experiment with rooting agents, one-cm long bases of the cuttings were dipped into solutions of IBA or NAA for 5 s, both at 0, 500 and $1000mg{\cdot}L^{-1}$ in 50% ethanol, and were also treated with Rootone$^{(R)}$ powder. Determined 90 days after cutting, the percent rooting and root weight were increased by NAA at $500mg{\cdot}L^{-1}$ in 'Bluecrop' and 'Sunrise', while in 'Duke' IBA at $500mg{\cdot}L^{-1}$ was effective. These auxin treatments were found to work better than a commercial product Rootone$^{(R)}$. The rooting agent-induced increases in root development resulted in better shoot growth of the cuttings in all three varieties, as determined after 90 days of further growth in individual containers. In the experiment with shading treatments, different levels of the shading treatment (30 to 90%) were imposed over the cutting bed under no mist. In all three varieties, 30% shading increased the percent rooting and root and shoot growth, compared to no shading control. However, shading levels higher than 50% shading were found to be inhibitory for hardwood cuttings of highbush blueberries, especially under the environmental conditions with no mist system.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.190-194
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• 2011

Potassium (K) is one of the essential nutrients for plants but is not a constituent of any plant compound. K is substances for activation of many enzymes and influences the process that the enzymes are involved in catalyzing. Although experimental results associated with the K effects with both benefits and no effects on turfgrass growth were reported, the limited research results of K effects on turfgrass among K sources are available in Korea. The objectives of the study was conducted to evaluate responses of Kentucky bluegrass (Poa pratensis L.) treated by fertilizer treatments with six K sources. There were six fertilizer treatments as K sources applied to Kentucky bluegrass which were potassium nitrate (13-0-44, PN), potassium chloride (0-0-60, PC), potassium sulfate (0-0-50, PS), polymer-coated potassium sulfate (0-0-45, PPS), potassium thiosulfate (0-0-25, PT), and potassium sulfate granulated with methylene urea (20-0-25, PSU). Potassium of $8g\;m^{-2}$ and N of $5g\;m^{-2}$ was applied 4 times giving a total 20 and $30g\;m^{-2}$, respectively. Although significant differences were found for turfgrass color, quality, chlorophyll index, and clipping dry weight, no consistent results among K sources were found during the one year study. Overall, K treatments didn't affect turfgrass growth in this study.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.174-179
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• 2012

The majority of turfgrass composition of golf courses are zoysiagrass, and mingle with cool-season turfgrasses have been increased. As result of mingling the species, invading problem has been raised. In this study, 50 golf courses nationwide were surveyed of grass composition and invading problem with hetero-species of turfgrasses. Among the courses, 47 golf courses have invading problem with more than one species at least. The invading problem has been issued most of golf course in nationwide. Thirty-seven courses composited with zoysiagrass; at 25 courses showed creeping bentgrass invading and at 33 courses were invaded by kentucky bluegrass. Among 47 kentucky bluegrass composition courses, 43 courses had creeping bentgrass invading problem. Invading problem within the grass species (creeping bentgrass in zoysiagrass, kentucky bluegrass in zoysiagrass, creeping bentgrass in kentucky bluegrass); 14, 12, and 21 courses were detected single species, two species, and three species invading problem, respectively.

• Korean Journal of Organic Agriculture
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• v.28 no.2
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• pp.209-221
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• 2020

Highbush blueberries (Vaccinium corymbosum), 'Duke', 'Bluecrop', and 'Elliott', were applied with ground cover mulch systems to evaluate bush growth and fruit characteristics. Soil temperature variation was lower in the woodchip mulching plot. Therefore, CEC, soil pH, phosphate, mineral ions were not significantly different among mulching materials. The number of main stem was higher in woodchip > sawdust > rice husk > plastic film mulching plot, respectively. Total shoot number was also higher in organic mulching plots than in plastic film plot. However, total shoot number was not significantly different among the organic mulching plots. Fruit weight was the highest in the woodchip mulching plot of all blueberry cultivars, however, soluble sugar content, organic acidity, fruit firmness were not significantly different in mulching materials. Yield was higher in organic mulching plots than in plastic film plot in all blueberry cultivars. Especially, yield per shrub of woodchip plots was the highest about 3.6 kg in 'Duke', 2.7 kg in 'Bluecrop', and 2.6 kg in 'Elliott'. Furthermore, correlation of main stem number and yield was highly significant (r² = 0.8413). Therefore, woodchip mulching is expected to be an eco-friendly method to increase the number of stems and the yield of blueberries.

• Weed & Turfgrass Science
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• v.3 no.1
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• pp.41-49
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• 2014

Four preparations of liquid turfgrass fertilizers were tested cool season turfgrasses during fall season. The preparations of PS-A, PS-B, PH-C and PH-D for commercial products were contained with essential nutrient elements, seaweed extract, amino acids, and humus substance. Growth and quality of creeping bentgrass (Agrostis palustris Huds cv. Penn-A1) and Kentucky bluegrass (Poa pratensis L.) mixture (Midnight 33%, Moonlight 33%, Prosperity 33%) were evaluated by normalized difference vegetation index (NDVI), root length and fresh weight, shoot density, turf color, and chlorophyll content. Three foliar sprays of 4 preparations with an interval of 7 days were made in the fall of 2013 in the sod production field at Hapchun, Korea. No significant difference among 3 preparations was found in NDVI of creeping bentgrass. However, PS-A was significantly increased NDVI of Kentucky bluegrass. Two to three applications of PS-A significantly increased chlorophyll content and turf color. Three foliar sprays of PS-A and PS-B were significantly increased the shoot density of Kentucky bluegrass on 20 days after final application. These results may indicate that the use of some preparation is beneficial in producing higher quality turfgrass sod with better color and chlorophyll content during fall season.