• Asian Journal of Turfgrass Science
• /
• v.24 no.2
• /
• pp.125-130
• /
• 2010

Dollar spot and brown patch disease are the most economically important disease for highly maintained turfgrass area such as golf courses. Previous researches indicated that various natural fertilizers are good nitrogen (N) sources and they may lead to turf disease suppression because disease suppression by natural N sources may be due to microbial activity increased. Increased microbial activities in soil reduce the activity of plant pathogen. The objective of this study was to evaluate efficacy of various N sources to suppress dollar spot and brown patch on creeping bentgrass. The seven N sources and fungicide combinations were investigated for turf disease suppression. $Emerald^{TM}$ and $ProStar^{TM}$ were applied for the applications of fungicide combination. No differences were found on turf quality among N source treatments. However, there was significant difference on turf quality between fungicide combination and fungicide combination plus urea. Overall, N source had no significant effects on suppression of dollar spot and brown patch. Although there were a few differences among N source treatments, fungicide treatments were needed for turf disease suppression for highly maintained turfgrass area such as golf courses.

• Horticultural Science & Technology
• /
• v.33 no.3
• /
• pp.340-348
• /
• 2015

Mowing turfgrasses, especially fast growing species like perennial ryegrass, is one of the most time and money consuming tasks of their management. Trinexapac-ethyl (TE) is a popular plant growth regulator used to reduce mowing requirements, improve stress tolerance, and enhance turf quality. This study was conducted to investigate the effect of TE rate and frequency of applications on growth response and traffic tolerance of perennial ryegrass. The experiment was a split-plot laid out in a randomized complete block (RCB) design with three replications. TE was applied to main plots at 0.00, 0.25, and $0.50kg\;a.i.\;ha^{-1}$. Application pattern included an initial application, followed by two sequential applications at 6-wk intervals. Traffic treatment was applied to subplots with a cleated roller. Results demonstrated that TE consistently reduced vertical shoot growth, clippings dry weight, with maximum growth reduction of 59% and 65%, for 0.25 and $0.50kg\;a.i.\;ha^{-1}$, respectively, occurring at 2 weeks after initial TE treatment (WAT). Traffic also dramatically reduced vertical shoot growth and clippings dry weight. Overall, quality of perennial ryegrass was enhanced by sequential TE applications, however, turf quality and surface coverage reduced greatly under traffic, regardless of TE treatment. Total chlorophyll, chlorophyll a and chlorophyll b and total carbohydrates (TC) contents were also positively influenced following sequential TE application. Our results indicated that TE reduces mowing frequency and enhances turf quality rather than influencing traffic resistance.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.26 no.4
• /
• pp.221-226
• /
• 2006

This study was conducted to investigate the effect of tall type mixtures and turf type mixtures on dry matter yield, botanical composition and quality. The experimental design includes two mixture types : Tall type mixtures; orchardgrass (Potomac) 50+tall fescue (Fawn) 20+ Kentucky bluegrass (Kenblue) 10+red clover (Kenland) 20%) and turf type mixtures; Kentucky bluegrass(Newport) 60%+tall fescue (reboil Jr.) 20+perennial ryegrass (palmer II) 20%. The DM yield was higher obtained in tall type mixture than that of turf type mixture (p<0.05). In the chemical composition, Turf type mixture was higher in crude protein (CP) and dry matter digestibility (DMD), but lower in fibrous compound as NDF, ADF, cellulose and lignin than those of tall type mixture (p<0.05). The crude protein dry matter (CPDM) and digestible dry matter (DDM) yield was higher in tall type mixture than turf type mixture (p<0.05). In this experiment, nutritive value of turf type mixture was higher than that of tall type mixture, but CPDM and DDM yield of turf type mixture were lower than that of turf type mixture due to low dry matter yield. On the other hand, turf type mixture was obtained high feed value, and maintaining the various botanical composition on the 13 th cutting frequency condition. therefore, turf type mixture had a utilization possibility under grazing livestock as sheep and milk goats.

• Weed & Turfgrass Science
• /
• v.3 no.4
• /
• pp.347-353
• /
• 2014

This study was conducted to investigate the effects of composted liquid manure (CLM) on soil properties and turf quality of zoysiagrass. The CLMs were produced at 5 facilities for livestock excretions treatments located in Cheongwon, Gunwi, Iksan, Nonsan, and Yeoju in Korea, respectively. Field experiments were conducted at 5 golf courses and a sod farm located near each facility for livestock excretion treatments. Chemical fertilizer (CF) with N at $12g\;m^{-2}year^{-1}$ and CLMs were applied four times, respectively. The constituents of the different CLMs were variable based on when and where the fertilizer was produced. Soil K content significantly increased when the soil was treated with CLMs. The soil treated with CF showed a higher content of total P than that treated with CLM. CF and CLMs treatments significantly increased the turf color index compared with control. Tiller density and shoot dry weight of fertilized plots were also higher than those of non-fertilized plots. However, there was no significant difference in turf color index and tiller density among plots treated by CLMs or CF. The results of this study demonstrated that CLMs could be a substitute for CF.

• Horticultural Science & Technology
• /
• v.30 no.6
• /
• pp.635-641
• /
• 2012

In Korea, slurry composted and biofiltered (SCB) liquid fertilizer is produced through the composting and biofiltering of animal waste. An appropriate guidelines involving proper treatment of SCB liquid fertilizer on turfgrass should be considered. An experiment was conducted to determine the optimum application amount, timing, and frequency of SCB liquid fertilizer for Zoysia japonica 'Millock'. The SCB liquid fertilizer was applied in low, medium, and high amount (N at 15, 25, and 40 $g{\cdot}m^{-2}$ per year in 2010, and 10, 20, and 40 $g{\cdot}m^{-2}$ per year in 2011, respectively) and treated during the growing season or dormancy period. During the growing season, SCB liquid fertilizer was applied twice or four times. The greatest improvement in turf quality for both years was in SCB plots applied four times with N at 40 $g{\cdot}m^{-2}$ per year during the growing season (SH4). This treatment exhibited turf color retention in the fall, and enhanced clipping yield during the growing and fall seasons. SCB plots with four times during the growing season (SL4, SM4, and SH4) exhibited higher shoot density relative to the same amount of other SCB treatments. Plots treated during the dormancy period also showed a high turf color index during the next growing season in 2011. The results indicate that SCB with high amount up to N at 40 $g{\cdot}m^{-2}$ per year applied four times during the growing season and dormant application produced high turf quality and growth, and could be recommended as an optimum application guide.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.24 no.2
• /
• pp.137-144
• /
• 2004

The objective of this experiment was to suggest the optimum N fertilization level for turf type mixtures {Kentucky bluegrass(Newport) 40% + tall fescue(Rebell Jr.) 20%. + perennial ryegrass(Palmer II) 10% + redtop(Barricuda) 10% + red fescue(Salem) 10% + creeping bentgrass(Crenshaw) 10%}. The field trials were conducted from 1998 to 2000 at Chungnam National University in order to evaluate the dry matter yield and quality on the N levels(100, 150 and 200kg/ha). With increasing the N level, the average DM yields over 2-years of turf type mixtures significantly increased. The average total DM yields were obtained 6,551, 8,182 and 9,501kg/ha at N 100, 150 and 200kg/ha level(p<0.05), respectively. CP content and DMD were increased, whereas fibrous constituents was decreased(p<0.05), but CPDM and DDM yields were significantly increased with increasing the N levels over 2-year(p<0.05). Based on the results, considering the total DM yield and the quality of herbages which were incidentally produced from turf type mixtures, it can be suggested that the suitable N level was 200kg/ha. But increased N fertilizer usage for general purpose use and expenses on turf type mixtures should be considered in advance.

• Weed & Turfgrass Science
• /
• v.4 no.4
• /
• pp.405-412
• /
• 2015

Forty schools having natural turf playgrounds were investigated by on-spot investigation and oral interviews with relevant school officials to find out basic information on turfgrass management practices of school playgrounds in Gyeonggi province. Average area of playground was $3,890m^2$ per school and $12m^2$ per student. Ninety five percent of turf playgrounds were managed by school staff and ninety percent of schools spent less than 5 million won per year for turf management. The difficulties in turfgrass management were considered as a major challenge for the schools, followed by turfgrass management cost. Among the management practices, school officials pointed out weed management as the most difficult work, followed by irrigation. The average number of fertilization and mowing was 2 and 6 times per year, respectively. About the half of playgrounds were irrigated only when there was wilting symptom. Zoysiagrass was the most popular choice for the school playgrounds and only three school playgrounds were established with pop-up irrigation system. Fourteen school playgrounds had good turf quality but the rest of school playgrounds had inadequate turf quality requiring minor or full renovation.

• Weed & Turfgrass Science
• /
• v.6 no.1
• /
• pp.61-66
• /
• 2017

The appropriate level of irrigation for turfgrasses is vital to the performance of the turfgrass as well as conservation of water. Linear gradient irrigation system (LGIS) facilitates long-term study of turf performance under continuous irrigation gradients at extreme ends of the irrigation scale. The objectives of this study were to: a) determine the minimum irrigation requirements and relative drought resistance in three warm season turfgrasses; and b) evaluate the medium to long-term effects of irrigation levels on turf persistence, weed invasion, and susceptibility to diseases. Results suggest that grasses differed in drought resistance and persistence under variable irrigation regimes. Irrigation (Ep) required for consistent acceptable turf quality for respective grasses was Cynodon dactylon x C. transvaalensis (61%), Zoysia matrella L. Merr (73%), and Stenotaphrum secundatum 'Palmetto' (86%). Brown patch infection was most prevalent in Stenotaphrum secundatum 'Palmetto' at 12 and 125% Ep irrigation. Cynodon dactylon x C. transvaalensis and Zoysia matrella L. Merr were better able to adapt to the various irrigation regimes, and this ability allowed these species to resist drought, and maintain turf coverage which in turn, kept weeds and the occurrence of diseases at bay. Ranking these grasses for their drought tolerance abilities showed that Cynodon dactylon x C. transvaalensis had the most outstanding resistance against drought, followed by Zoysia matrella L. Merr, and lastly, Stenotaphrum secundatum 'Palmetto'. Despite having the highest irrigation requirement, Stenotaphrum secundatum 'Palmetto' was still not able to maintain persistence at high irrigation regimes. Likewise, this grass also lost turf coverage at low irrigation levels.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.8 no.5
• /
• pp.10-18
• /
• 2005

The research was carried out to define the morphological and growth characteristics of Poa pratensis L.(Kentucky bluegrass) 'Sewon' in native to Korea. Poa pratensis 'Sewon' was collected at the terrace land on the river in Guiman-ri, Cheongcheon-myeon, Goesan-gun, Chungcheongbuk-do on May 5, 1995. The collected Poa pratensis 'Sewon' was grown under non-mowing naturally growing condition. The morphological characteristics of Poa pratensis 'Sewon' are as follows. : The height of plant was 21.6cm but was increased to 33cm at the flowering time. The height of first node from the base was 5.0cm and the length and width of leaf were 9.6cm and 4.1cm, respectively. The length of inflorecences was 37.8cm and the length of a spike was 7.3cm. Based on these morphological characteristics, Poa pratensis 'Sewon' was defined to dwarf~medium and coarse texture type Kennturky bluegrass. 1 to 9 scale of visual quality, visual color and visual density were measured. Poa pratensis 'Sewon' showed best turf qualities among native Kentucky bluegrasses. In spring and fall growing season, Poa pratensis 'Sewon' were measured to be excellent performances for turf qulities similar to foreign excellent quality cultivars such as Midnight, Nuglade and Brilliant Kentucky bluegrasses. But turf quality of Poa pratensis 'Sewon' decreased by plant disease according to temperature increase in summe compared to foreign excellent quality cultivars. So, Poa pratensis 'Sewon' should be improved of disease tolerent quality by incessant breeding work in order to compete foreign excellent quality cultivars.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.27 no.2
• /
• pp.101-108
• /
• 2007

The object of this experiment was to investigate the effect of mixture which consist of different seeding rates and species on dry matter yield and quality in Daejon area. The field trials were conducted from 2003 to 2005 at Chungnam National University in order to evaluate the dry matter yield and quality of different mixture. The experimental design includes three mixture types: Conventional mixtures, CM{orchardgrass(Potomac) 50% + tall fescue (Fawn)20% + Kentucky bluegrass(Kenblue) 20% + white clover(Regal) 10%}, red clover + mixtures, RM{orchardgrass(Potomac) 40% + tall fescue(Fawn) 20% + Kentucky bluegrass(Kenblue) 10% + red clover(Kenland) 30%) and Turf type grass + mixtures, TM {orchardgrass (Potomac) 50% + turf type grass (tall fescue, Millennium 20% + Kentucky bluegrass, Midnight 10% + perennial ryegrass, Palmer III 10%) + white clover(Regal) 10%}. The average DM yield for 2 years of red clover+mixture(11,656kg/ha) was higher than those of the other mixtures(p<0.05). The content of crude protein and dry manu digestibility were higher in red clover+mixture than in other mixtures(p<0.05). but, the content of fibrous compounds like as NDF, ADF, cellulose and lignin were lower in red clover+mixture than in other mixtures(p<0.05). The crude protein dry matter(CPDM) yield was higher in red clover + mixture(2,832kg/ha) than in conventional mixture(2,372kg/ha) and turf type + mixture(2,266kg/ha)(p<0.05). The digestible dry matter (DDM) yield was higher in red clover + mixture(8,881 kg/ha) than in conventional mixture(8,255kg/ha) and turf type + mixture(7,314kg/ha)(p<0.05). In botanical composition at last cutting time in 2005, conventional mixture were maintained orchardgrass 45%, tall fescue 22%, Kentucky bluegrass 5% and white clover 24%. Red clover + mixture were maintained orchardgrass 40%, tall fescue 22%, Kentucky bluegrass 4% and red clover 31%. turf type + mixture were orchardgrass 37%, tall fescue 23%, Kentucky bluegrass 6%, perennial ryegrass 8% and white clover 24%, respectively. As summary, DM yields and quality of mixture species and seeding rates were observed significant difference. The results of this experiment indicated that red clover + mixture was more effective in enhancing the DM yield and forage quality in Daejon area.