• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.59-68
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• 2011

Research was initiated to investigate the effect of high water-absorbing polymer on turf grass quality of three major turfgrasses. A total of 12 treatment combinations were used in the study. Treatments were made with different rates of sand, soil organic amendment (SOA), and water-swelling polymer (WSP). Visual turf grass quality was evaluated in creeping bentgrass (Agrostis palustris Huds., CB), Kentucky bluegrass (Poa pratensis L., KB), and zoysiagrass (Zoysia japonica Steud., Zoy) grown under greenhouse conditions. Significant differences were observed among the treatments in CB, KB, and Zoy. Visual quality ratings varied with mixing rates of SOA and WSP, being maximum 5.6 in differences among them. At the end of study it ranged from 0.3 to 9.6 in CB, 0.3 to 4.0 in KB, and 0.9 to 5.8 in Zoy. Turfgrass quality pattern changed with time after seeding among treatments influenced by WSP rates. From this study, a proper rate of WSP is considered to be 5%, 5~10%, and 5% for CB, KB and Zoy, respectively. In general, overall treatment effect of WSP on turfgrass quality was highly associated with SOA 20% in three turtgrass species. When mixing sand with SOA and WSP for rootzone soil, a proper rate of SOA is considered to be 15 to 20% for CB and KB, while 20% for Zoy of warm-season grass. A further study would be required to investigate the effect of varied, gradual mixing rates of WSP on growth characteristics of turfgrasses grown on mixtures of sand, SOA, and WSP before a field application.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.229-236
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• 2011

This study was carried out to provide recent information on zoysiagrass (Zoysia spp.) sod production in Japan. Total zoysiagrass sod production acreage in Japan was 6,623 ha. The acreage by prefecture was 3,900 ha (58.9%) in Ibalaki, 779 ha (11.8%) in Tostoli, 609 ha (9.2%) in Kagosima, and 550 ha (8.3%) in Sijeumoka, respectively. Sod was harvested by 1.5 cm sod thickness. Mowing height of Goraisiba (Zoysia matrella) and Nosiba (Zoysia japonica) cultivars was cut by 10 mm and 25 mm height, respectively. Japan agricultural cooperative issued a warranty of sod production quality to zoysiagrass consumers. A quality evaluation for sod production was carried out continuously to maintain a reasonable degree of uniformity and hight quality of sod production three times a year. Also, zosiagrass sod production was rotated with Chinese cabbage (Brassica rapa var. glabra Regel) for improving fertility of soil every five to six years. Patented cultivars for promoting bland in Ibaraki prefecture of Japan were 'Tsukuba himae', 'Tsukuba kagayaki', 'Tsukuba Talou' and 'Tsukuba green'.

• Asian Journal of Turfgrass Science
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• v.26 no.2
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• pp.116-122
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• 2012

The study was conducted to know whether turfgrass wear tolerance, growth, and quality could be improved by the application of silicon and potassium. First, turf responses to silicate and potassium were evaluated by several parameters such as, turf visual quality, root length, shoot density, and dry weight under the field condition. Second, turf responses to traffic frequencies were examined by turf growth (root) length, shoot density and dry weight) and soil hardness under the field condition. Finally, under traffic stress condition, the effects of silica and potassium application on wear tolerance were evaluated through the methods described above. Creeping bentgrass (Agrostis stolonifera) rooting were significantly improved by silica. The root length was enhanced by an increase in potassium silicate application. Certain level of light traffic is beneficial while frequent traffic cause serious adverse effect on visual quality of bentgrass. Under a traffic stress condition with 10 times of footing a day for 30 days, silica and potassium increased turf visual quality by 6.38% and 10.25% respectively when compared to the control. Silica and potassium treatment on trafficked plot increased turf visual quality by 11.4% and 10.2% respectively in comparison with the control with significant reduction of wear injury from the traffic. A co-application of potassium silicate with potassium sulfate provided the enhanced visual quality of turf as compared to application of silica or potassium fertilizer, respectively.

• Asian Journal of Turfgrass Science
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• v.19 no.2
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• pp.151-160
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• 2005

Research was initiated to investigate seasonal turf quality under a sand-based USGA soil system. USGA system 45 centimeters deep was built with rootzone layer, intermediate layer, and drainage layer. Six turfgrass entries were comprised of 3 blends and 3 mixtures from cool-season grasses (CSG). Turfgrass quality ratings were best in spring and fall, especially early May to early July and late August to early November. Kentucky bluegrass(KB) consistently produced the greatest quality, while perennial ryegrass (PR) the poorest. Intermediate turf quality between KB and PR was observed with tall fescue (TF). Among CSG mixtures it increased with KB but decreased with PR. There were considerable variations in summer turf performance. No summer drought injury was found in KB and TF. However, PR showed poor performance through summer as compared with other CSG. Results demonstrate that KB was the best and PR the worst among CSG grown in a sand-based USCA soil system.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.3
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• pp.1-12
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• 2000

식물생장조절제(Plant Growth Regulators, PGRs)를 이용한 예초관리 방법이 들잔디 엽색 및 품 질에 미치는 영향을 규명함으로 잔디 적응력 관점에서 적합한 PGR 종류 및 살포수준을 파 악하고자 본 연구를 시작하였다. 실험은 들잔디 생육이 왕성한 시기인 6월(실험 I)과 7월(실험 II) 2회에 걸쳐 각각 다른 장소에서 실시하였다. 공시약제 처리구는 Type I PGR인 amidochlor 3 수준 및 mefluidide 3 수준 과 Type II PGR인 trinexapacethyl 4 수준, 그리고 무처리구를 포함하여 전체 11 처리구였 고, 실험구 배 치는 난괴법 4 반복으로 하였다. 공시한 3종류 PGR 모두 잔디엽색 및 품질에 통계적으로 유의한 차이 가 있었지만, PGR 종류.살포수준 및 생육 상태에 따라 처리효과는 다르게 나타났다. 잔디 엽색 및 품질 은 PGR 살포후 경과기간에 따라 점진적으로 억제되는 경향이었다. 처리 1주후 잔디품질은 대조구에 비 해 큰 차이가 없었지만, 2주에서 4주까지는 PGR 종류 및 살포수준에 따라 유의하게 감소하 여 0.08 ml/ $m^2$ 이상의 trinexapac-ethyl 처리구 및 1.20 ml/$m^2$ 이상의 mefluidide 처리구에서는 가장 크 게 나타났다. 처리 4주부터 대부분 처리구에서 잔디품질이 적정수준 이상으로 회복되기 시작하였다. 본 실험을 통해 잔디관리 수준에서 저관리 잔디지역은 0.08 ml/$m^2$ 수준의 trinexapac-ethyl 처리구가 장기간 생장억제 관점에서 실용성과 경제성 측면에서 들잔디 관리에 효율적인 것으로 판단되었고, 고관리 잔 디지역은 0.04~0.08ml/$m^2$ 수준의 trinexapac-ethyl 처리구 및 0.60~1.20 ml/$m^2$ 수준의 amidochlor 처 리구가 적합 한 것으로 판단되었지만, 계절에 따라 PGR 효과정도가 다르게 나타났다. 따라서, 잔디 관리 시 잔디의 생육상태, 예초 절감 기간, 잔디품질의 기대수준 및 적용할 수 있는 관리수준에 따라 적합한 PGR 종류 선정과 함께 살포시기 및 살포량을 효율적으로 결정하는 것이 필요한 것으로 사료되었다.

• Weed & Turfgrass Science
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• v.6 no.4
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• pp.333-344
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• 2017

This study was conducted to examine the effect of cool-season grass overseeding on the green period, turf quality and density in zoysiagrass lawn. Treatments were perennial ryegrass (PR) overseeding ($60g\;m^{-2}$) on medium-leaf type zoysiagrass, Kentucky bluegrass (KB) overseeding ($20g\;m^{-2}$) on medium-leaf type zoysiagrass and narrow-leaf type zoysiagrass, and no overseeding on medium-leaf type zoysiagrass. Overseeding of KB or PR effectively provided quality improvement of zoysiagrass lawn by extending green-period about one month in spring and two months in fall season. PR overseeding showed quick green cover within 2-3 weeks but decreased the quality of overseeded zoysiagrass lawn during the summer season. Whereas, KB overseeding showed slow green cover taking two to three month after seeding but provided stable and good turf quality throughout the years. KB or PR overseeding significantly increased the turf density of zoysiagrass lawn except the period of summer depression of PR. The ground coverage of cool-season grasses ranged from 30 to 80% with considerable seasonal variation. As a result, KB and PR have their strengths and weaknesses as an overseeding material. Thus, the use of KB and PR as a mixture would provide better overseeding performance in zoysiagrass lawn.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.249-255
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• 2015

Trichoderma spp. were famous fungi used for turfgrass management in golf course. This study was conducted to evaluate effects of two microbial fertilizers containing Trichoderma harzianum and T. atroviride on the growth and quality of creeping bentgrass with turf color index, chlorophyll index, root length, shoot number, clipping yield and nutrient content. Treatments were designed as follow; non-fertilizer (NF), control fertilizer (CF), T. harzianum (TH), and T. atroviride (TA). Chlorophyll index and root length of TH and TA were increased than these of CF and shoot number and content and uptake of nitrogen (N) of TA higher than these of CF. The N content in turfgrass tissue was significantly related to shoot number, root length and N uptake (P<0.05) and shoot number was positively relate to chlorophyll index (P<0.05). These results indicated that application of Trichoderma harzianum and T. atroviride improved a growth and quality of creeping bentgrass by promoting N uptake.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.259-268
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• 2013

This study was carried out to evaluate the visual turfgrass's color quality, winter color, and spring green-up under three different soil systems and to make a practical use for sports turf design and construction. Several turfgrasses were evaluated in multi-layer, USGA and mono-layer systems. Turfgrass entries in the study comprised of 3 cultivars from Korean lawngrass (Zoysia japonica Steud.) of typical warm-season grass (WSG) and 3 blends and 3 mixtures from Kentucky bluegrass (KB, Poa pratensis L.), perennial ryegrass (PR, Lolium perenne L.), and tall fescue (TF, Festuca arundinacea Schreb.) of cool-season grass (CSG). Significant differences were observed in the turfgrass's color quality, winter color, and spring green-up in the study. Seasonal variation of visual turf color greatly occurred according to soil systems and turfgrasses. Multi-layer and USGA systems were highly associated with better visual color ratings, as compared with mono-layer system. Regardless of soil system, visual turf color in all entries was better from spring to fall than in winter. Great color differences were observed during a period of early December to early spring. CSG produced a better color quality over WSG in any soil system. Overall color ratings for CSG were KB > PR > Mixtures > TF. As for a winter color, its ranking was USGA > multi-layer > mono-layer system. No difference was found in winter among cultivars of Korean lawngrass, being completely brown, but great differences among CSG. Rated best for winter color was PR, followed by CSG mixtures, KB and finally TF in order. It was generally conceded that fast green-up in spring was greatly related with multi-layer over mono-layer system and also CSG over WSG. Among CSG, TF had a fastest green-up. PR was also fast in green-up, but poor in color uniformity. KB, however, was the slowest due to shallow rooting system, when compared with other CSGs. These results demonstrate color differences were greatly variable according to soil systems and also among turfgrass species. A precise decision should be made in selecting turfgrass species and soil system. Multi-layer and USGA systems were considered as the suitable one for turfgrass color quality, winter color and spring green-up. It is a great necessity to combine proper soil system, right turfgrass species, and appropriate mixing rates by a concept-oriented approach, when establishing garden, parks, soccer field, and golf courses and so on.

• Weed & Turfgrass Science
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• v.7 no.1
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• pp.62-71
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• 2018

This study was conducted to evaluate the effect of liquid fertilizer containing humate (LFH) on changes of turfgrass quality and growth by investigating visual quality, chlorophyll content, dry weight of clipping, and nutrient content in leaves tissue. Treatments were designed as follows; control fertilizer (CF), HF-1 ($CF+1.0mL\;m^{-2}\;LFH$), HF-2 ($CF+2.0mL\;m^{-2}\;LFH$), and HF-3 ($CF+4.0mL\;m^{-2}\;LFH$). As compared with CF, soil chemical properties of LFH treatments were not significantly. Visual quality and root dry weight of LFH treatments were higher than that of CF. Chlorophyll content, clipping yield and nitrogen uptake of HF-2 and HF-3 were increased 11.2-11.8%, 15.3-30.0%, 22-42% by application of LFH. The LFH level was positively correlated with visual quality, chlorophyll content, clipping yield or nutrient uptake amount. These results indicated that the application of LFH improved the growth and quality of creeping bentgrass by increasing nutrient uptake and by prompting root growth.

• Weed & Turfgrass Science
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• v.5 no.1
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• pp.42-50
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• 2016

Superintendents have been used microbial fertilizers to improve turfgrass growth and quality and to decrease turfgrass diseases in golf course. This study was conducted to investigate the effects of compound fertilizer containing microbe (MF) on the growth and quality of creeping bentgrass with turf color index (TCI), chlorophyll index (ChI), root length, turfgrass density, clipping yield and nutrient content. Treatments were designed as follows; non-fertilizer (NF), compound fertilizer (21-17-17; CF) as control, compound fertilizer (14-6-17) containing microbe. In pot experiment, TCI and ChI of creeping bentgrass in MF plot were similar to those in CF. But clipping dry weight of MF plot increased by 39.1% compared to that of CF plot. At field experiment applied with MF treatment, TCI, ChI, root length, and nutrient content and uptake of creeping bentgrass were similar to those with CF treatment, but turfgrass density with MF higher about 7.9-15.8% than with CF. These results indicated that the application of MF improved growth and quality of creeping bentgrass by enhancing clipping yield and shoot number.