• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.287-294
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• 2009

This study conducted to evaluate the growth characteristics of creeping bentgrass in summer after application of the plant growth regulator, Trinecapac-ethyl, and these data may provide basic information to golf course turf maintenance. The results showed that the shoot density of creeping bentgrass was increased an average density of 1.7 $ea/cm^2$ with the trinexapac-ethyl application, especially about 2 $ea/cm^2$ during the growth retarded period of June and July. The root length increased also in June and August. The visual quality was improved significantly with trinexapac-ethyl treatment all the experimental periods, moreover, the effect was significant by reducing a summer decline stress of creeping bentgrass during the warm and humid period of summer. The green speed was significantly improved by this growth regulator treatment and those effect was prominent during stressed season of late June to mid July. Overall of the result, we found that shoot density, visual quality and green speed of bentgrass green were improved by trinexapac-ethyl treated from early growing season of spring and these effects were continued during summer. It should be very beneficial to manage the bentgrass green in stressed season. In future, the possibility and efficiency of mixture with fungicides and/or fertilizers might be needed. The spring green-up test with trinexapac-ethyl will be followed in next spring.

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.1-10
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• 2011

This study was conducted to investigate early germination characteristics and germination pattern of new cultivars of creeping bentgrass (CB, Agrostis pall/stris Huds.) under natural room temperature conditions and to analyze differences between alternative and natural conditions. Seven cultivars of CB were tested in the study. Daily and cumulative germination patterns were measured and analyzed on a daily basis. Significant differences were observed in germination pattern, days to the first germination, days to 50% germination, days to 85% germination, and germination rate among cultivars under different environments. The first germination in all entries was initiated between 4 and 5 days after seeding (DAS) under alternative conditions, while between 6 and 8 DAS under natural conditions, being 2 to 3 days later as compared with that of alternative conditions. As for the first germination percentage, it was generally 5 to 25% under alternative conditions. However, 'Penn A-1', 'Penncross', and 'Penn A-4' cultivars showed a vigorous germination, producing 50 to 70%. Under natural room temperature conditions, it was 5 to 10% for the most entries, except 'Penncross', 'L-93', and 'Penn A-4' cultivars which vigorously produced 20 to 50%. Days to the 50% germination in CB resulted in 4 to 10 DAS under alternative conditions, while 6 to 15 DAS under natural conditions, being 2 to 5 days later than under alternative conditions. Days to the 85% germination were 5.90 to 11.75 DAS under alternative conditions and 7.95 to 12.50 DAS under natural conditions. 'Penn A-1' and 'L-93' were the fastest cultivars under alternative and natural conditions, respectively. Regardless of the temperature conditions, the longest cultivar in germination was 'T-1', being over 11 DAS. In-depth comparative data on germination characteristics and germination patterns among CB cultivars would be usefully applied for a practical CB turf establishment in golf course construction etc.

• Asian Journal of Turfgrass Science
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• v.22 no.2
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• pp.217-223
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• 2008

This study was conducted to figure out the effect of silicate as growth stimulator on growth of 'Pencrosss' creeping bentgrass. Creeping bentgrass(Agrostis palustris cv. 'Pencross') at the nursery of Sinwon Country Club was used. Silicate was applied at the concentration of 0, $200{\times}$, $500{\times}$, $1.000{\times}$. Polt size was 1 by 2 meter and there were three replications with completely randomized design(CRD). Creeping bentgrass growth was evaluated with visual turf grass quality, root length and No. of tiller density(ea/$cm^2$). Results of this study are as followings; 1. Average root length with silicate was $1.5{\sim}1.9cm$ longer than control. Especially, Root length of silicate was $7{\sim}8cm$ in summer. 2. Tiller density with silicate was $l8{\sim}22ea/cm^2$, $0.4{\sim}2.l$ less than control. But there was no significant difference. 3. Visual turfgrass quality with silicate was $5.0{\sim}8.3$, $0.3{\sim}1.5$ higher than control. But there was no significant difference. In conclusion, silicate might be grown as root growth stimulator of creeping bentgrass during summer in Korea. However, this study was conducted under one year. Accordingly, in-depth experiment should be done over several years.

• Asian Journal of Turfgrass Science
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• v.26 no.2
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• pp.110-115
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• 2012

Soil amendments have been used to improve the physical and chemical condition of turf soil, which might optimize turfgrass growth in golf courses. This study was to investigate the effect of inorganic soil amendment (ZC) established in USGA root zone system on growth of creeping bentgrass, cv. 'Penncross' carried out from May to Dec. in 2005 at the nursery on Sinwon Golf Course. To analyze the effects of inorganic soil amendment on pH, specific gravity, infiltration rate, water content, soil hardness, root length, tiller density and dry weight were measured. pH was 6.7-6.8, specific gravity of sand (S) 100% was 1.48 heavier than the other treatments (1.28-1.38). Infiltration rate with ZC 15% + peat moss (P) 5% + S 80% and ZC 10% + S 90% was faster than S 100%. Soil hardness of S 100% was the highest. Root length of creeping bentgrass of P 10% + S 90% (8.6-12.0 cm) was the longest. Tiller density with P 5% + S 95% was more 4-7 ea than other treatments in summer season. In growing season, however, ZC 10% + P 5% + S 85% was more 2-3 ea than others. Dry weight of creeping bentgrass treated by ZC 10% + P 5% + S 85% in summer season and P 5% + S 95% in growing season were heavier than other treatments. It is recommended to combine 5-15% inorganic soil amendment and peat moss 5% with sand in order to sustain soil balance.

• Weed & Turfgrass Science
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• v.7 no.3
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• pp.259-268
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• 2018

This study was conducted to evaluate the effect of liquid fertilizer containing humic acid and Saccharomyces cerevisiae broth (LHS) on changes of turfgrass growth by investigating visual quality, chlorophyll content, dry weight of clipping, and nutrient content in leaf tissues. Treatments were designed as follows; control fertilizer (CF), HS-1 ($CF+1.0mL\;m^{-2}\;LHS$), HS-2 ($CF+2.0mL\;m^{-2}\;LHS$), and HS-3 ($CF+4.0mL\;m^{-2}\;LHS$). After treatment of LHS on creeping bentgrass, soil pH in the treated plots was decreased than that of CF. As compared to CF, visual quality, chlorophyll content and content of N, P and K were not significantly different in the LHS treatments. However, clipping yield and phosphorus uptake of HS-2 were significantly increased by 22% and 33%, respectively. These results showed that application of LHS improved the phosphorus uptake and growth of creeping bentgrass, which would be an alternative management tool for the cool season turfgrass under stress conditions.

• Weed & Turfgrass Science
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• v.6 no.3
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• pp.272-281
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• 2017

This study was conducted to evaluate the effect of liquid fertilizer containing humic acid (LFHA) on changes of creeping bentgrass quality and growth. Treatments were designed as follows; control fertilizer (CF), HA-1 ($CF+1ml\;m^{-2}LFHA$ LFHA), HA-2 ($CF+2ml\;m^{-2}LFHA$ LFHA), and HA-3 ($CF+4ml\;m^{-2}LFHA$). As compared with CF, soil chemical properties and chlorophyll content of clipping of LFHA treatments were not significantly different. Visual quality in both of HA-2 and HA-3 treatments was higher than that of CF treatment from September to November, and clipping yield on October 27. Shoot density, root length, and the content of nitrogen, phosphorus or potassium were increased by application of LFHA. The clipping yield was positively correlated with phosphorus content, potassium content or shoot density. Similarly, LFHA level was proportionate to clipping yield of creeping bentgrass, and N, P, K contents in the leaf tissue. These results generally demonstrated that the application of LFHA improved the growth and quality of creeping bentgrass by increase of N content or P in leaf tissue.

• Weed & Turfgrass Science
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• v.3 no.3
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• pp.246-252
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• 2014

This study was conducted to evaluate the effects of two amino acid fertilizers on the growth of creeping bentgrass and N uptake. Fertilizer treatments were designed as follows; non-fertilizer (NF), control (CF), recommended amount (ALF), double amount (2ALF) of amino acid liquid fertilizer (AaLF), recommended amount (ASLF) and double amount (2ASLF) of amino acid liquid fertilizer contained with saponin (AaSLF). Turf quality of treatments of AaLF and AaSLF such as turf color index, chlorophyll index and root length was similar to the treatment of CF. Dry weight and content, uptake and availability of N were investigated highest in the 2ALF and 2ASLF. These results suggested that foliar application of AaLF and AaSLF was enhanced turf quality and growth of creeping bentgrass by stimulating uptake and availability of N.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.260-267
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• 2016

Amino acids in the plant were intermediate metabolites which produced by uptake and assimilation of nitrogen and these extracts which gained by bio-chemical digestion from protein of plant or animal were a source of functional fertilizer. This study was conducted to evaluate effects of keratin amino acid fertilizer (KAF) gained from animal hair or hoof on changes of turfgrass quality and growth by investigating turf color index, chlorophyll index, shoot number, clipping yield, and nutrient content in the turfgrass tissue. Treatments were designed as follows; non-fertilizer (NF), compound fertilizer (CF), keratin amino acid fertilizer treatments [CF + KAF $0.26ml\;m^{-2}$ (CKF), CF + KAF $0.52ml\;m^{-2}$ (2CKF)], and only keratin amino acid fertilizer treatment (KF). Shoot number, clipping yield, and nitrogen uptake of KF were higher than those of CF. As compared with CF, soil chemical properties, turf color index, chlorophyll index and clipping yield of keratin amino acid fertilizer were not significant, but shoot number and uptake of N and K were increased significantly. These results show that the application of keratin amino acid fertilizer increased shoot number and growth by increased uptake of nitrogen and potassium.

• Asian Journal of Turfgrass Science
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• v.21 no.2
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• pp.155-161
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• 2007

This study was initiated to evaluate the growth characteristics of creeping bentgrass cultivars during the sprlng season. The green-up of 'CY' and 'T-1' were about 2 weeks earlier than the other cultivars followed by 'Penn A' 'Crenshaw', 'L> 'Penncross' > 'Putter' > 'Dominant' > 'SR1020' in that order. 'T-1' and 'CY-2' had the highest chlorophyll content while 'Penncross' had the lowest during the spring. 'Crenshaw' and 'Penn A-4' showed the highest shoot density in this research, followed by 'CY-2', 'L-93', 'T-1', 'Putter', 'Dominant', 'SR1020', and 'Penncross' in that order. In case of root length, 'CY-2' and 'L-93' were the best cultivars, but 'Penncross' was worst during the spring. 'CY-2' had the best visual quality among the cultivars, 'T-1' and 'Crenshaw' also classified as high visual quality group whereas 'SR1020', 'Dominant' and 'Penncross' were grouped in relatively low quality. In conclusion, 'CY-2', 'T-1' and 'Crenshaw' were the best cultivars in terms of growth characteristics in spring. Conversely, 'SR1020' and 'Penncross' were the poorest cultivars. These results can be more useful for management or constructing of golf courses. However, this research was performed with little compaction stress. More information is needed on the tolerance to compaction stress of these bentgrass cultivars.

• Asian Journal of Turfgrass Science
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• v.17 no.1
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• pp.13-17
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• 2003

This study was conducted to figure out the effect of KOB Soil on creeping bentgrass‘Cobra’, Kentucky bluegrass (KB)‘Midnight’75% + Perennial ryegrass (PR)‘Palmer III’25%. This experiment was conducted from September 1, 2001 to August 31, 2002 at Hwajoulryong in Jeongsun County, Gwangwon-do. Treatments were Sand 80% + Peatmoss 20%, Sand 80% +KOB-Soil (No. 1) 20%, and Sand 80% +KOB-Soil (No. 2) 20%. Treatments with KOB Soils was superior to control fer the leaf length, number of leaf, turf quality and root length in Creeping bengrass and Kentucky bluegrass + Perennial ryegrass.