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

• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.167-174
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• 2006

This study was initiated to investigate the effect of chitosan on creeping bentgrass growth. Chitosan was applied several times in dilution of 300, 500 and 800 times at ten-day intervals after transplanting. Such growth characteristics as leaf length, root length, numbers of leaves, fresh weight and dry weight and chlorophyll content were observed. Treatment of 500 times diluted chitosan resulted in the longest root length, being 31.5cm while the control the shortest root of 25.1cm. Leaf numbers were 27.9 and 45.5, respectively for the control and the 300 times treatment. The highest chlorophyll content was associated with treatment of 300 times diluted chitosan and the lowest one with the control, resulting in 11.9 and $18.4mg/100cm^2$, respectively. We found that leaf number, chlorophyll content, fresh and dry weight were higher in the treatment of 500 times than the other treatments.

• Asian Journal of Turfgrass Science
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• v.23 no.1
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• pp.35-44
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• 2009

This study was carried out to examine the growth performance of 4 species of cool-season grasses and 4 species of zoysiagrasses under salt injury in Seo-san reclaimed area. Grasses were grown on the plots with capillary water interruption layer (WCWIL) and without capillary water interruption layer (WOCWIL) soil systems. Cool-season grass and seeding-type zoysiagrass plots were seeded on 6 Jun, 2006. Vegetative zoysiagrass 'Junggi' was established by sprigging and 'Senock' and 'Millock' were plugged. Electric conductivities of irrigation water (ECw) ranged from 0.28 to $3.3\;dS{\cdot}m^{-1}$. Electric conductivities (ECe) of the soil with capillary water interruption layer and without capillary water interruption layer ranged from 0.55 to $9.4\;dS{\cdot}m^{-1}$ and from 1.84 to $9.4\;dS{\cdot}m^{-1}$ respectively. Leaf color, turf quality, coverage rates, and growth rates were rated visually for 2 years. Zoysiagrass 'Junggi', creeping bentgrass, zoysiagrass 'Senock' and 'Millock' showed acceptable growth at salty fairway condition, while Kentucky bluegrass, perennial ryegrass, Kentucky bluegrass mixed with perennial ryegrass, and seeded zoysiagrass 'Zenith' showed establishment rates below 70%. These results will be useful when choosing turf grass species and cultivars for the golf courses in reclaimed land area.

• 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.

• 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.6 no.4
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• pp.322-332
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• 2017

Microbial fertilizer has been used to prompt turfgrass growth and quality and to prevent turfgrass diseases in turfgrass management of golf courses. This study was conducted to evaluate effects of microbial fertilizer containing Lactobacillus fermentum (MFcL) on changes of turfgrass quality and growth by investigating turf color index, chlorophyll index, clipping yield, and nutrient content in the turfgrass tissue. Treatments were designed as follows; non-fertilizer (NF), control fertilizer (CF), MFcL treatments [CF+$1.0g\;m^{-2}$(MFL), CF+$2.0g\;m^{-2}$ (2MFL)], and only MFcL treatment (OMF; $1.0g\;m^{-2}$ MFL). Chemical properties of soil by application of MFcL was unaffected. Turf color index, chlorophyll index, clipping yield and nutrient content and uptake of MFcL treatments were similar to CF. Furthermore, turfgrass shoot density of MFL was increased by 20% than that of CF, and that of OMF by 22% than NF. These results show that the application of microbial fertilizer containing L. fermentum increased turfgrass shoot density, which is not attributed to nutrient uptake in this study, but needs to be further investigated with other mechanisms such as biostimulant induction or phytohormone production.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.147-152
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• 2011

This study was conducted to evaluate the growth characteristics of creeping bentgrass cultivars for fairway of golf course at Yeoju area in Korea. At germination and coverage rate of creeping bentgrass, 'Shark' and 'CY-2' were excellent, 'L-93', 'Alpha', 'T-1 was in order', respectively. Visual qualities of 'Shark' and 'CY-2' also were excellent. Especially, 'Shark', 'T-1', and 'CY-2' showed excellent visual quality in summer days, the critical times for the bentgrass fairway quality. 'Shark', 'CY-2' and 'T-1' were excellent in Chlorophyll contents throughout the evaluation period. Chlorophyll content of 'T-1' was maintained very high in summer. 'CY-2' and 'Shark' showed the best root growth at the beginning of the study and contained longer and hairy roots. Which might make these two cultivars' water absorption easier than other's. NDVI (normalized difference vegetation index)of 'Shark', 'L-93' and 'CY-2' was excellent, respectively. 'T-1' showed the highest density and 'Shark', 'CY-2', 'Alpha', 'L-93' was followed by. The density of 'T-1' was rather increased in summer season, while those of other cultivars were decreased. Three diseases such as anthracnose, brown patch, and dollar spot, were appeared during the evaluation period. 'T-1' and 'L-93' were very sensitive to anthracnose which occurred at the beginning days of the study. The most susceptible cultivars to brown patch were 'Alpha' and 'L-93'. 'T-1' was the least resistant to dollar spot which occurred at the same time with brown patch.

• Weed & Turfgrass Science
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• v.7 no.2
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• pp.148-157
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• 2018

Research was initiated to evaluate four domestic and overseas organic soil amendments (SAs) on turfgrass groundcover and density and to provide basic information on practical sports turf establishment. This study was conducted in Agrostis palustris Huds. (CB) grown in sand-based root zone. A total of 20 treatments of SA+sand were prepared by mixing 10 to 50% (v/v). These amendments were SABP (Berger Peat), SAEP (Eco-Peat), SAGS (G1-Soil), and SAPP (Premier Peat). Turfgrass groundcover and density significantly varied with SAs, its mixing rate to sand and week after seeding (WAS). Cumulative turfgrass density was variable, but a great change occurred between 2 and 4 WAS. Turfgrass density at 2 WAS ranged from 36.7 (SABP 30) to 89.7% (SAGS 20), being 53.0% in differences among treatments. However, CB reached to carrying capacity around 6 WAS. Thus, most treatments were similar to 90% or so in density. At the end of study, overall groundcover ranged between 60.7 (SAEP 10) and 96.7% (SAPP 50). Proper mixing rate was variable with SAs, being 10 and 20% for SABP and SAGS, respectively. But the optimum rate was 50% for both SAEP and SAPP.

• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.241-252
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• 2009

This study was carried out to check the possibility of substituting bottom ash from the Seosan power plant for sand as growing media for creeping bentgrass (Agrostis stolonifera L.) under saline irrigation condition. Characteristics of growing media were evaluated by using column and leaching method. Creeping bentgrass cv. Pen-A1 was grown in pots with dredged up sand (DS) and bottom ash (BA) media those were amended using 1%, 2%, and 3 % OM rates in a green house. The plants were irrigated with 1.5 $dSm^{-1}$ saline water. Results showed that visual quality, plant height and shoot dry weight from DS treatment were higher than those of BA treatment. Even though BA contained more salts, repeated leaching could decrease ECe efficiently. In case of no OM amendment, the visual quality, plant height and shoot dry weight were similar between in BA and DS. Amendment of 2% OM increased the height of creeping bentgrass in DS, while decreased the plant growth in BA.

• Asian Journal of Turfgrass Science
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• v.22 no.2
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• pp.149-160
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• 2008

This study was carried out to examine the growth performance of 10 cultivars of creeping bentgrass under salt injury in Seo-san reclaimed area. Turfgrass performance studies included 10 creeping bentgrass cultivars (T-1, L-93, Penn A1, Pennlinks II, Seaside II, Declaration, Penn A4, Crenshaw, Dominant, and Penncross). Ten creeping bentgrass cultivars were grown on a USGA recommended research green. Plots were seeded on May 31, 2006 at the rate of $7\;g{\cdot}m^{-1}$. Electric conductivities of irrigation water (ECw) and soil (ECe) were ranged from 0.28 to $3.3\;d\;S{\cdot}m^{-1}$ and from 0.25 to $3.5\;d\;S{\cdot}m^{-1}$ respectively. Leaf color, turf quality, coverage rate, and growth rate were checked under the salty condition in reclaimed land for 2 year. Creeping bentgrass cultivars of T-1, Penn links, and Crenshaw presented dark green color and Penn A1, Declaration showed lighter green color. Penn A1, Penn A4 and L-93 exhibited the highest overall turfgrass quality. Average visual coverage was 75.3% after eleven weeks after seeding. Dominant, L-93, and Penn A1 resulted in higher visual coverage compared to the other cultivars. There was no difference in density among cultivars at 1 year after establishment. However, Declaration, Penn A1, T-1, and L-93 showed higher density compared to the other cultivars at 2 years after seeding. Creeping bentgrass showed different quality, density and color in salty soil (ECe: $0.25-3.5\;d\;S{\cdot}m^{-1}$) and from application of salty irrigation water (ECw: $0.28-3.3\;d\;S{\cdot}m^{-1}$) conditions. These results will be useful where selecting green cultivars for the golf courses in reclaimed land area.