• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.295-306
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• 2009

We investigated the quality of 48 cultivar in 5 types, most popularly used in Korea golf courses. Only brown patch disease caused by Rhizoctonia solani AG1-1 was occurred naturally. While disease was developed seriously into tall fescue cultivar in spring time and into bentgrass cultivar in fall time, respectively, however, among species were not significantly different. Tall fescue and perennial ryegrass cultivar had higher chlorophyll contents in November and there were also significantly different between cultivar of tall fescue, kentucky bluegrass and fine fescue species. Turfgrass color also showed significant difference between grass species. Perennial ryegrass has the highest value of turf leaf color, followed by kentucky bluegrass and tall fescue species. Significant differences among cultivar were found in kentucky bluegrass, tall fescue and fine fescue. Although fresh weight of turfgrass was not statistically different between grass species, root length was significantly different between species. Tall fescue species had the longest root length. Fresh weight showed differences among cultivar in kentucky bluegrass, bentgrass and tall fescue species. Based on our results, growth and grass quality showed large differences among cultivar and each turfgrass species.

• Asian Journal of Turfgrass Science
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• v.6 no.1
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• pp.1-10
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• 1992

This experiment was carried out to investigate the effect of mixing ratio of soil amending materials such as peat. perlite, active carbon, and zeolite on the growth and quality of creeping bentgrass (Agrostis pa1ustris var. Penncross). The results of this experiment were surnrnarized as follows; 1.Nitrogen content of clippings was increased by the treatment of peat and active carbon. hut the other phosphorus, potassium, calcium and magnesium content were increased in addition of,5% to 10% of peat, and 2.5% to 5% of active carbon. 10% of perlite. and 4% of zeolite 2.Fast growth and good quality of bentgrass were showed at the addition of 10% peat. l0% perlite.2.5~% active carbon, and 4% zeolite But over treatment of peat and active carbon induced inhi-bition of root growth and occurrence of disease.

• Asian Journal of Turfgrass Science
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• v.3 no.1
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• pp.39-52
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• 1989

Native Kerean lawngrass (Zeysia japonica steud.) and Manilagrass ( Zeysia matrella Merr.) are frequently used as sport turf and lawn in Kerea and ether Asian countries because of its excellent summer qualities and superior winter-hardiness compared to ether warm-season turfgrass . The objective of this study was to investigate the effect of the plant growth retardants ( PGR ) en the inhibition (d the growth of the two Kerean native turfgrasses. Kerean lawngrass and Manilagrass were treated with [2 RS , 3 RS] -1- [4- chlorophenyl ] -4, 4-dimethyl -2- [1 H -1, 2, 4- tiazol -1- y] pentan -3- ol ( PP -333) at 93 and 930 gha -j ; 5-[4- chlorphenyl ]-3, 4, 5, 9, 10- peiitaaza - tetracyclo [5, 4, 1, 0 2 6 . o ~'~I -3, 9- diene ( BAS -106) at 16 and 160 gha ; [ E I-] - cyclohexyl -4, 4- dimethyl -2- [1, 2, 4- triazol -1- yl ]-1-pentene - 3- ol ( NTN -821) at 56 and 560 gha ', and 4- chloro -2- [$\alpha$- hydrozybenzy I isonicotin anilide ( CGR -811) at 92 gha in pot study . All PGR treatments were effective in reducing the plant height, with the exception of BAS -106 at 16 gha for Korean lawngrass ; however , all increased quality to some degree , with the exception of PP -333 at 93 gha . The low PGR rates significantly increased Korean lawngrass height during late jtily aitd mid-August . On the other hand , BAS -106 significantly increased Manilagrass height {rom 24 Septeml)er onwards . All PGR treatments haol higher turfgrass quality than untreatments , and also the high rates of PGIt treatments were more effective in increasing quality than the low rates observed on 8 October . Meanwhile , Manilagrass quality was increased to some extent than Korean lawegrass . PP - 333 was significantly effective in reducing clipping yield and the same results were found with the application of NTN -821 at 560 gha -l for both Korean lawngrass and Manilagrass , BAS -106 at 160 gha for Korean lawegrass , and CGR -811 at 92 gha for Manilagrass . The high PGR rates had higher turfgrass shoot weight observed on 8 October than the low rates , and there were little increases obtained with the low rates of PP -333 for Korean lawngrass and BAS - 1 06 for Manilagrass . Effeets on stolon growth varied between growth retardants , and between retardant treatments ; the high rates of PGR as well as the low rate of NTN -821 elongated stolon of Korean lawngrass and manoilagrass . However , PP -333 at 93 gha and BAS -106 at 16 gha - shortened stolons of Korean lawugrass , resulting in inhibition or little difference of stolon dry weight . NTN -821 at 560 gha and CGR -811 had no positive effect on the stolon length of Manilagrass . 101) -333 and the low rate of BAS -106 and NTN -821 decreased root weight of Korean lawng - rass All PGR rates had negative effect on the root weight of Manilagrass with the exception of BAS -106 CR -811 and the high rate of NTN -821 which made no difference in root weight between retarolant treatments and the control .

• Asian Journal of Turfgrass Science
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• v.13 no.1
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• pp.29-36
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• 1999

This study was conducted to make the utmost use of the good traits and to improve the poor traits of zoysiagrass through the production technology for mixed lines sod in addition to breeding. Mixed lines sod was produced by mixing broad or middle leaf line with narrow leaf line by volume, a ratio of 1 to 2. The mixed lines sod of zoysiagrass was superior to the single ling sod, which is used commonly, for the establishment rate, coverage rate, shoot density, texture, leaf color, dormancy period cnd color, and visual quality.

• Weed & Turfgrass Science
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• v.6 no.3
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• pp.262-271
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• 2017

This study was conducted to evaluate incorporation ratio of soil amendment 'Profile' to improve soil physicochemical properties and turfgrass growth. The soil amendment was added 0 (sand only), 3, 5, 7, and 10% to USGA Green-spec green sand soil. As incorporated with more 'Profile' amendment, soil electrical conductivity (EC), cation exchangeable capacity (CEC), capillary porosity and total porosity of root zone were increased than those of control, while bulk density and hydraulic conductivity decreased. Turfgrass index and clipping yield of creeping bentgrass grown in sand soil incorporated with 7% 'Profile' were improved than those of control. Correlation coefficient of turf color index and incorporation ratio of the soil amendment 'Profile' was found to show significantly positive correlation. These results indicated that application of the soil amendment 'Profile' to sand soil in golf course green improved turfgrass growth and quality by increasing CEC and porosity of root zone.

• 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.

• Asian Journal of Turfgrass Science
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• v.21 no.2
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• pp.177-182
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• 2007

When a football field is constructed using sand medium, the fertilizer management has to be adjusted because of the low nutrient holding capacity and higher leaching rate. The objective of this study was to test the effects of slow release fertilizers on Kentucky bluegrass (Poa pratensis L.) growth in simulated sport field rootzones with PVC pipe pots. Data of turfgrass color, uniformity, growth rate, biomass above ground, and the nitrate content in the leaching solution was collected at different growing stages and during four simulated rain fall periods. The result showed that the nutrient release rate of urea was the highest and that of controlled release nitrogen fertilizer was the lowest. Effects of the controlled release nitrogen fertilizer lasted 14 days more than other lawn fertilizers and 28 days longer than regular urea with acceptable quality levels of turf. The slow release fertilizer also restrained excessive growth of the grass, reduced the times of mowing. Slow release fertilizer used in this study reduced $NO_3$-N leaching by almost 50% at the beginning of turf establishment.

• Weed & Turfgrass Science
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• v.7 no.1
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• pp.76-86
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• 2018

Turfgrass species were evaluated for their rooting and foliar characteristics, and their interaction with the soil. The rooting system was divided into three compartments, one above another, such that the top and bottom compartments of the root system could be supplied with a nutrient deprived solution. Exposure of parts of the roots to nitrate deprivation caused a localised retardation of root initiation and extension, compared with zones receiving the full supply of nutrients. This resulted in considerable modification to root form, coupled with a significant depression in foliar growth. The extension of roots was the least affected by the deprivation of potassium. Phosphate and calcium deprivations gave rise to similar responses in root and foliar formation. Results from this study showed that external concentrations of nitrogen, phosphorus, potassium and calcium are required by the root system in varying amounts for optimal growth of roots. Turfgrass coverage and turf quality ratings further reinforced these findings. No significant difference was observed between the different grasses examined here. All three species responded similarly to the deprivation of the various nutrients. Results from this study confirmed that targeted fertilization programs are beneficial and can help reduce cost, chemical usage and prevent leachate and contamination.

• Asian Journal of Turfgrass Science
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• v.16 no.2
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• pp.75-83
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• 2002

The back-filled soil of the New Incheon International Airport construction site was reclaimed with sea sand in near the Young-Jong island. The primary study was carried out from August 1993 to June 1997 to study soil amendment and to select salt resistance turfgrass species. This study dealt with low maintenance area that included most part of open space of airport site. The second experiment, from October 1996 to August 1998, focused on soil amendment and selection of turfgrass species for alongside runway where turf area was maintained. Through two previous studies, propagation methods with zoysiagrass were tested for alongside runway and surrounding areas at 1998. The study of construction methods with zoysiagrass, vegetative propagation showed better results on visual quality and cover rating compare with seeding propagation. However, significant different between vegetative and seeding propagation was not showed on visual quality and drought tolerance after one year of plot establishment. The cover rating by seeding construction methods reached in excess of 70% of limitation suggested by the Incheon International Airport Cooperation. Zoysia net and sprigging net methods were the most suitable where there requires rapid and high rate of ground cover. Seeding propagation should be acceptable to obtain a resonable cover rating where there allows relatively longer period of completion. Therefore, it should be possible to attain a proper rating of ground cover on the site of open space, alongside runway or areas similar to the New Incheon International Airport which is being built on dredged seashore sand. However, the methods of soil amendment, selecting salt tolerance species, and proper construction procedure should be considered at the a time.