• Asian Journal of Turfgrass Science
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• v.1 no.1
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• pp.18-29
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• 1987

This study was carried out to examine the effect of nitrogen application and clipping interval on the characteristics of several turf components of korean lawngrass for the basic data of lawn management. It was treated by Split plot design with three replications. The main plots were nitrogen levels with 0, 350, and 700kgN / ha, and the sub plots were clipping intervals with 10, 20, and 30 days The results obtained are summarized as follows ; 1. Increasing the rate of nitrogen fertilizer and frequent clipping increased tiller number of korean lawngrass and the maximum number of tillers obtained in October were recorded from 700kgN application and clipping treatment of 10 days interval. Meanwhile, treatment of 350kgN with 10 days clipping interval increased tillers much more than those of 700kgN with 20 and 30 days clipping intervals. 2. The average number of green leaves occurred during the growth period maximized by applying 700 kgN and clipping 10 days interval. 3. Increasing tiller numbers significantly decreased tops DM weight per tiller by clippng plants at interval of 10 and 20 days, irrespective of nitrogen applied, and with nil N, at the interval of 30 days. By applying 700kgN however, tops DM weight per tiller increased as the number of tillers increased consistently. 4. The highest tops DM weight was achieved from late August to early September by applying 350 and 700kgN. 5. During the growth period, nitrogen application increased unders(stolon+root) DM weight, and, at the same level of nitrogen applied, the increase in stolon DM weight enhanced by lengthening the clipping interval to 30 days. 6. Nitrogen efficiency to green leaves, stolon nodes and DM weight of root with high nitrogen was achieved as clipping interval was shortened.

• Horticultural Science & Technology
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• v.34 no.2
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• pp.342-353
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• 2016

This study was initiated to evaluate green color retention under three different soil systems. Several turfgrasses were evaluated in multi-layer, USGA, and mono-layer systems. Turfgrass entries were comprised of three cultivars of Korean lawngrass (Zoysia japonica Steud.) as warm-season grass (WSG) and three blends and three mixtures of Kentucky bluegrass (KB, Poa pratensis L.), perennial ryegrass (PR, Lolium perenne L.), and tall fescue (TF, Festuca arundinacea Schreb.) as cool-season grass (CSG). Significant differences were observed in visual turf color and green color retention among soil systems and turfgrasses. Both the multi-layer and USGA systems were highly associated with better color ratings and longer color retention, as compared with the mono-layer system. Seasonal variation of visual turf color greatly occurred from late December to early spring. CSG exhibited longer color retention than did WSG. The latter maintained green color for approximately 6 months, regardless of the soil system. Spring green-up of Korean lawngrass occurred from early to middle May, while it underwent discoloration from late October to early November. Among the CSGs green-up occurred between early March and early April and leaf color was maintained until middle December to early February. Therefore, the CSGs were green for 8.5 to 11 months, depending on turfgrass and soil system. The mean period of green color duration across all soil systems was approximately 10-11, 9-10 and 8.5-9.0 months for PR, KB and TF, respectively. As for the CSG mixtures, the greater the proportion of PR, the longer the green color retention, while the higher the proportion of TF, the shorter the color retention. There was greater variation in green color duration among the CSGs than the WSGs. Across soil systems, color retention differences of 2 to 6 days were observed for the Korean lawngrass, but 7 to 36 days for the CSGs. These results demonstrate that green color retention varied greatly according to soil systems and also among turfgrasses. Selections of turfgrass and soil system should be made using a concept-oriented approach, when establishing garden, park, soccer field, golf course and other sports field. Information obtained in this study can be used to select soil systems and turfgrasses based on the expected degree of leaf color retention.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.1
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• pp.129-136
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• 2010

This study was initiated to investigate thatch accumulation in several turfgrasses grown under two soil systems. The 45 centimeter deep USGA system was constructed with rootzone, intermediate and drainage layers. The mono-layer system, however, was made with only a 30cm rootzone layer. Turfgrasses used in the study were comprised of 3 varieties from Korean lawngrass of Warm-Season Grass(WSG) and 3 blends and 3 mixtures from Cool-Season Grass(CSG). A total of 9 turfgrass treatments were replicated three times in RCBD in both systems. Cultural practices for the research plot followed a typical maintenance program for highly managed turf. Treatment differences for thatch accumulation were observed among the turfgrasses in both soil systems. Thatch under the USGA system was 9% greater than under the mono-layer system due to its more favorable conditions for turf growth. Higher thatch depth was found with Korean lawngrass, 34~87% in the USGA system and 16~75% in the mono-layer system when compared with CSG. Among WSG, the Joongji variety was the highest in thatch layer under both the USGA and mono-layer systems. Kentucky bluegrass(KB) was the greatest among CSG, since it is a rhizomatous-type in growth habit, resulting in faster production of organic matter over bunch-type of tall fescue and perennial ryegrass. Proper depth in the thatch layer was known to be beneficial by enhancing the resiliency and wear tolerance of the turf in athletic fields. Thus, KB was considered to be a very excellent turfgrass in terms of turf quality, environmental performance, physical properties and soccer player safety. However, disadvantages such as poor water-holding properties, more inclined to injury from environmental stresses and severe diseases and insect injury were also expected where thatch was excessively accumulated. Therefore, these results demonstrate that more frequent measures for controlling thatch such as vertical mowing, topdressing or coring should be employed for soccer fields with Korean lawngrass and KB over other turfgrasses.

• Asian Journal of Turfgrass Science
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• v.9 no.4
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• pp.293-316
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• 1995

Nitrogen fertilization and cutting practice were studied on turfgrasses and cover plants to investigate the possibility of maintaining green color during the growing season. Research also involved the effect of the nitrogen on a few morphological characteristics of leaf performance elements which might give an information to coloration and life-span of turf leaves. Treatments in the first experiment undertaken on pot included one N level: 350kgN /ha applied as compound fertilizer in split applications of one-half in mid-May and the rest both in late June and August, and four spring-summer cuts: late May, late June, late July and late August. The soil filled in pot a moderately well-drained sandy loam. In the second experiment(field observation) leaf length and width, inflorescence and flowering, and color performance were also investigated. With nitrogen fertilizer applied on turfs, desirable turf color was maintained during a period of poor coloration in specific seasons such as mid-summer for cool season grasses and late fall for warm season grasses comparing to the non-treatment. However, this was not stimulated by cutting treatment to nitrogen status existed. Cutting effect on coloration was more remarkable in both Korean lawngrass and Manilagrass than in cool season turfgrasses such as Italian rye-grass, perennial ryegrass and tall fescue. Especially down-slide of leaf color in cool season turfgrasses could he detected in mid-summer /early fall season ranging up to mid-September. In early November as well as mid-September, Italian ryegrass, perennial ryegrass and tall fes-cue retained a high level of green color as followed by nitrogen application and cutting treatment, and little detectable variation of leaf color notation between cool season turfgrasses was obtained. However, Korean la'vngrass and Manilagrass failed to retain the green color until early November. Color notations in cool season turfgrasses investigated early November on the final date of the experiment ranged from 5 GY 3/1 to 4/8 in 'Ramultra' Italian ryegrass, 'Reveile' perennial ryegrass and 'Arid' tall fescue, but those in Zoysiagrasses were 7.5 YR 4/8 in Korean lawngrass and 2.5 y 5 /6 in Manilagrass. Life-span of leaves was shorter in Italian ryegrass, perennial ryegrass and tall fescue than in beth Korean lawngrass and Manilagrass with and without nitrogen application. In general, leaves appeared in early May had a long life-span than those appeared in late April or mid-June. Nitrogen application significantly prolonged the green color retaining period in perennial ryegrass, Italian ryegrass, Korean lawngrass and Manilagrass, and this was contrasted with the fact that there was no prolonged life-span of leaves emerging in early May and mid-June in tall fescue. SPAD reading values in 48 turfs and cover plants investigated in the field trial were increasing until late June and again decreasing till September. Increasing trends of reading value could be observed in the middle of October in most of grasses. On the other hand, clovers and reed canarygrasses did not restore their color values even in October. Color differences between inter-varieties, and inter-species occurred during the growing season under the field condition implicated that selection of species and /or cultivars for mixture should be taken into consideration. In Munsell color notation investigated in the final date in the middle of November, 32 cultivars belonged under the category of 5 GY and 10 cultivars under the category of 7.5 GY. This was implying that most of cool season turfs and cover plants grown in the center zone of Korean Peninsula which are able to utilize for landscape use can bear their reasonable green color by early or mid-November when properly managed. The applicable possibilities of SPAD readings and Munsell color notation to determine the color status of turfgrasses and cover plants used in this study were discussed.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.2
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• pp.49-52
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• 2001

conditions for callus induction and plant regeneratin from seeds of lawngrass (Zoysia japonica Steud.) were confirmed in this study. MS (Murashige and Skoog) medium containg 2,4-D 3 or 5mg/l was used for callus induction, and MS medium with different volumes of BA, NAA and kinetin hormones was used to regenerate the plants from induced calli. MS basic medium containing agar with no hormones or kinetin 1.0mg/l and MS basic medium containing gelite and NAA 1.0mg/l were higher for green callus induction. MS medium containing agar and kinetin 1.0mg/l ws highest degree of efficiency for plant regeneration.

• Asian Journal of Turfgrass Science
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• v.10 no.3
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• pp.177-186
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• 1996

The effects of salt are studied on control of weeds and growth of Korean turfgrass(Zoysia japon-ica Steud.). And the mobility of salt were determined in a lawn field. At post-emergence stage, the growth of the 13 weeds such as Trifolium repens, Erigeron canadensis, Artemisia prieceps, Equi-setum arvense, etc were controlled by treatment of salt and salt water, Pea-annua and Equisetum arvense were tolerant to salt compared with the other 11 weeds. At pre-emergence stage, the salt controlled the germination of the weeds in soil. 300~500 kg /10a salt and 20~30 % salt waterwere enough for the control of weeds, However, salt water injuried the lawngrass except the dormancy stage. The mobility of salt in soil was increased by rainfall. After 160mm of rainfall, the salinity in the soil treated with salt 500kg /l0a was below 0.3 ms/cm in surface soil and about 0.1 ms /cm in soil 30 cm depth. Key words: Soil environmental survey, Korean turfgrass, Salt, Salt water.

• Asian Journal of Turfgrass Science
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• v.2 no.1
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• pp.31-40
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• 1988

4가지 관수 처리 회수가 한국 잔디와 Zoysia-82에 미치는 영향을 조사한 결과는 다음과 같다. 1. 한국 잔디가 각 관수처리마다 Zoysia-82보다 엽장은 길고 엽복은 넓은 편이었다. 2. Runner의 생장은 Zoysia-82가 왕성했으며, 두 품종 공히 매일 1회 관수, 대비구(자연상태), 5일, 10일마다 1회 관수구순으로 runner의 길이가 길고 1일 생장량도 많았다. 3. 이식시 단위 spring당 각 부위별 건물량은 한국잔디가 더 무거웠으나 생육을 거듭할수록 Zoysia-82가 더 무거웠고, 1일 건물량 증가량도 Zoysia-82가 더 많았다. 4.지표면 피복율은 각 관수처리별 Zoysia-82가 한국 잔디보다 빨랐다. 두 품종 공히 매일 관수구 가장 빨랐고, 대비구, 5일, 10일마다 1회 관수구 순으로 빨랐다.

• Asian Journal of Turfgrass Science
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• v.2 no.1
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• pp.59-64
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• 1988

This study was carried out to investigate the classification and the growing charicteristics of weed species in a newly formed lawngrass land. The results obtained are summarized as follows: 1)Weed population in a newly formed lawn field consisted of 30% of Gramineae, 15% of Compositae, and 12% of Leguminosae family. 2)Percentage of weed emergence between April and May was 39.4%. The same amount of weed emergence was observed at the period of September and October, where as the percentage was 21.2% at the period of March and April. 3)The population ratio of flowering date of weed species was in order of 48.5% July and August, 30.3% in May and July, 12.1% in March and April, and 9.1% in September and October. 4)Weed classification by life cycle showed 39.4% of biennials, 33.3% of annuals, and 27.3% of perennials. 5)Weed species were grouped according to the plant height. The ratios of each group were 33.3% of 20~40cm group, 27.3% of 40~60cm group, 24.2% of shorter than 20cm group, and 15.2% of taller than 60cm group.

• Horticultural Science & Technology
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• v.17 no.5
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• pp.572-577
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• 1999

Research was initiated to evaluate plant growth regulator effects on the vertical shoot growth of Korean lawngrass and to determine desirable growth regulator and its rate. The experiments were conducted twice at different sites in 1995. All the tested growth regulators inhibited the growth, but the inhibition period was variable among the product in Experiments I and II. During the first week after treatment, there was approximately 10 to 20% growth reduction in most of the treated plots. In the amidochlor-treated plots, growth suppression was effective for 3 to 4 weeks at low to medium rates ($0.60mL{\cdot}m^{-2}$). A Type II growth regulator, trinexapac-ethyl exceeding the medium rate of $0.08mL{\cdot}m^{-2}$ consistently tended to suppress vertical shoot growth for 8 weeks, being above 35% reduction in both experiments. In the plots applied with mefluidide, growth suppression appeared with foliar discoloration 3 or 4 days earlier than the other growth regulators and continued to work till the 8 weeks after treatment. Suppression intensity on vertical shoot growth increased with time after treatment up to a certain period of time, depending on growth regulators. Generally, the higher the application rate, the greater the suppression intensity. Seasonal variation of activity and effectiveness of growth regulators was observed, resulting in lower suppression intensity in July than in June. It is expected to reduce mowing requirements by 30 to up to 60% for a certain period with a specific growth regulator. In low to medium maintenance of Korean lawngrass turf, a long-term suppression may be more effectively accomplished with trinexapac-ethyl rather than mefluidide and amidochlor in terms of vertical shoot growth inhibition. Therefore, turf managers will need to select proper growth regulator and determine optimum rate of application for turfgrass management, based on a defined period of mowing reduction.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.4
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• pp.89-99
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• 2005

The golf courses more than about 200 are operating in Korea. From the golf courses, a great amount of turfgrass clippings tend to increase, steadily. Materials used in the experiment were Creeping Bentgrass(CB), Kentucky Bluegrass(KB), Korean Lawngrass(KL), rice bran and composted chicken drop. Treatments are CB, KB, and KL. The temperature during the composting of all treatments increased rapidly and reached at the highest temperature($57.9^{\circ}C$, $67.8^{\circ}C$, $74.3^{\circ}C$) within 20 days, and then stabilized to the range of $35.2{\sim}41.6^{\circ}C$ at the 30th day. The pH values of all treatments decreased on the first day. However, they were increased rapidly after three days and decreased again on 10~20 days. The pH values of all treatments at the final day were stabilized to the low alkali levels. The contents of total carbon during the period of composting tend to decrease and total nitrogen was increased for factor of reduction of volume. CEC value of all treatments during the period of composting tends to increase. The round paper chromatogram of extracted solution of KL sample was the sharpest and clearest among all treatments. The G.I. values of CB, KB, and KL in 30th day of composting were about 95.1, 77.7, and 98.7 in germination test using chinese cabbage, respectively. Conclusively, all turfgrass clippings used in this experiment were composted well, suitable as composting products standardized by KSC. The maturity of the final compost samples is best in KL, followed by CB and KB treatments. The turfgrass compost can contribute to the plant cultivation for environment-friendly farm, and the results of this study can become the basic data of turfgrass clippings compost. Further research on the mixing ratio of each material is required to produce compost of good quality.