• 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.

• Asian Journal of Turfgrass Science
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• v.20 no.1
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• pp.25-31
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• 2006

'Meyer' zoysiagrass(Zoysia japonica Steud.) is a popular turfgrass species used for transition zone golf course fairways and tees in mfd U.S.A golf courses because it is generally winter hardy while providing an excellent playing surface with minimal chemical and irrigation inputs. However, its functionality declines easily in many of the shaded areas of these courses. Reduced irradiance causes excessive shoot elongation, reduced tillering, and weak plants that are poorly suited to tolerate or recover from traffic and devoting. Trinexapac-ethyl (TE) effectively reduces gibberellic acid (GA) biosynthesis and subsequent shoot cell elongation. This study was initiated to evaluate TE effect on shoot elongation and stand persistence under two levels of shade in 'Meyer' zoysiagrass. A mature stand of 'Meyer' was treated with all combinations of three levels of shade(0%, 79%, and 92%) and three levels of monthly TE [0, 48 $g{\cdot}ha^{-1}$ a.i(0.5x) and 96 $g{\cdot}ha^{-1}$ a.i(1x)]. In full sun, the TE at 48 $g{\cdot}ha^{-1}$ a.i reduced clipping yield by 18% over a four-week period and, whereas the TE at 96 $g{\cdot}ha^{-1}$ a.i by 30% to 38%. Monthly application of TE at the 96 $g{\cdot}ha^{-1}$ a.i increased 'Meyer' tiller density in full sun and under 79% shade. Both rates of TE consistently reduced shoot growth under shade relative to the shaded control. Only the monthly applications of the TE at 96 $g{\cdot}ha^{-1}$ a.i consistently delayed loss of quality under 79% shade. Our results indicate TE can be an effective management practice to increase 'Meyer' zoysiagrass persistence in shaded environments.

• 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.6 no.1
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• pp.67-76
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• 2017

The study was initiated to evaluate the effects of overseeding warm-season grass (Zoysia japonica Steud.) with cool-season grasses (CSG) on turfgrass density, uniformity and tiller appearance and to determine turfgrass species and seeding rate applicable for a practical use. Treatments were comprised of Kentucky bluegrass (KB, Poa pratensis L.), perennial ryegrass (PR, Lolium perenne L.), tall fescue (TF, Festuca arundinacea Schreb.) and their mixtures. Overall turfgrass density and uniformity were much better with the overseeded treatments over the control. In early stage after overseeding, the greater the PR in treatments, the greater the turfgrass density and uniformity. But the higher the KB, the lower the density and uniformity. From the middle-stage evaluation, however, we observed the opposite results as compared with early-stage findings. Accordingly, the KB was highest in turfgrass density and uniformity, while the PR lowest. In regards of mixtures, both turfgrass density and uniformity were better with increased KB and decreased PR in overseeding rates. As for a medium-quality mixtures of Korean lawngrass with CSG, it would be the best choice to apply with KB at $50g\;m^{-2}$ and equal combination of KB, PR and TF by 1/3 in mixing at $75g\;m^{-2}$ in terms of sustainable density and uniformity.

• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.147-156
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• 2006

This study was initiated to evaluate the growth characteristics of seven creeping bentgrass cultivars in summer, 'Penncross' showed the worst visual quality, whereas 'Penn A-4' and 'Crenshaw' the best quality. 'Putter', which was maintained a fair quality during the test period, was regarded as a good cultivar because of no significant variation in summer as compared to the other caltivars. 'Crenshaw',' L-93' and 'Penn A-4' were greater in chlorophyll content and 'Penncross' lowest during the summer. Also, 'SR1020' had a low content of chlorophyll. 'Putter' greatly increased in chlorophyll content after fertilization. The highest shoot density($19.3/cm^2$) was found with 'L-93' in early August, followed by 'Crenshaw', 'Penn A-4', 'Putter', 'Dominant', and 'SR1020' in that order. However, 'Penncross' was lowest($15.7/cm^2$). As for a root length, 'L-93' was longest, being over an average 5.5cm. 'Penn A-4' and 'Putter' also showed good result in root growth. However, the root length considerably decreased with 'SR1020', 'Penncross' and 'Dominant' in summer. Brown patch was a serious disease for the most cultivars, except 'Penncross'. 'Dominant' had the most serious damage. 'Putter', 'L-93', 'Crenshaw', 'SR1020', and 'Penn A-4' were also greater in damage over the others. In regards of algae occurrence in summer, 'Penn A-4' had the least damage, while 'Dominant' the greatest. In conclusion, 'Crenshaw', 'Penn A-4' and 'L-93' were the best cultivars in terms of summer growth. Conversely, 'Penncross' was the poorest one. However, this study was conducted under the conditions of one-year old green. Accordingly, in-depth experiment should be done over several years to elucidate the characteristics of growth for the wide range of creeping bentgrass cultivars during the summer.

• Asian Journal of Turfgrass Science
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• v.24 no.2
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• pp.145-148
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• 2010

Nitrogen (N) is one of the most important nutrients among 17 essential nutrients for maintaining turfgrass color and quality. The slow release fertilizers were initially developed to provide a more consistent release of nitrogen over a longer period and are often used to decrease leaching potential from sandy soils. The goal of this study is to determine if various slow release N sources affect the rate at which turfgrass establishes. Six nitrogen sources were evaluated; Nitroform (38-0-0), Nutralene (40-0-0), Organiform (30-0-0), Sulfur coated urea (SCU, 37-0-0), urea (46-0- 0), and Milorganite (6-0-0). The root zone media was seeded and sodded with 'Limousine' Kentucky bluegrass (Poa pratensis L.). Sodded pots produced 182 to 518 g more clipping dry weight than seeded pots. Among seeded pots, Milorganite produced greater amount of root dry weight than any other N sources. Because the period of turfgrass growth is different between sodded and seeded plots, there were differences on clipping yield and root growth. Overall, high N rate had turf color greater than acceptable color of 6 among seeded pots throughout the study. However, low N rate didn't produce acceptable turf color throughout the study. Based on the result of this tudy, ilorganite would be ecommended for new establishment of Kentucky bluegrass an urea with less clipping yield which can lead to reduce abor.

• Asian Journal of Turfgrass Science
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• v.26 no.1
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• pp.54-59
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• 2012

This study was conducted to evaluate to the effect of liquid fertilizer with saponin (SLF) and liquid fertilizer with amino acid (ALF)on the growth of creeping bentgrass. In creeping bentgrass, turf color index, chlorophyll index, dry weight and shoot number were measured. It was hardly affected by SLF and ALF applications in investigation of chemical properties of the soil. By applying SLF and ALF, turf color index and chlorophyll index in 2SLF and 2ALF were increased more than CF, and shoot number and root length in 2SLF, ALF and 2ALF were higher than CF. In correlation coefficient among growth factors of creeping bentgrass, turf quality was significantly different in root length, shoot number, dry weight, and content of N and K in turf tissue (P<0.05), N content of tissue was significantly in root length, shoot number and dry weight (P<0.05), and K content was significantly in shoot number and dry weight (P<0.05). These results suggested that application of functional liquid fertilizers such as SLF and ALF was expected to replace compound fertilizer in turf management and that applied SLF and ALF was stimulated the uptake of N and K into turf so that turf qualities were improved by enhancing growth shoot and root of turf.

• Weed & Turfgrass Science
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• v.5 no.3
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• pp.155-164
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• 2016

Earworm is very useful animal in soil ecosystem, however it is harmful for golf courses because they introduce many cast on turfgrass that reduces turf uniformity and play quality. However, no information has found on earthworm diversity and seasonal fluctuation in different Korean golf courses. In this study, we focused to carry out earthworm species composition and seasonal population structure in turfgrass of golf courses. During spring and fall season survey with direct digging and tea saponin drenching sampling in 5 different golf courses, 6 species under 3 families of earthworms were collected. Earthworm species composition and density was different among the golf courses. Aporrectodea caliginosa in Lumbricidae was dominant species in Anseong and Dongrae Benest Golf Club; however Amynthas carnosus in Megascolecidae was dominant species in Anyang and Glenrose Golf Club. Ap. caliginosa was collected only aclitellum in July and Am. carnosus was collected aclitellum and clitellum in August in golf courses. Seasonal population of earthworm was different depending on earthworm species (Am. hupeiensis was the highest in August and Ap. caliginosa was in April) however small number of collected earthworm species were not dominant trend in golf courses.

• 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.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.1
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• pp.13-23
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• 2016

This study was conducted to investigate the growth characteristics of warm-season turfgrasses and to find out suitable turfgrass species on Saemangeum reclaimed land. Twenty native zoysiagrass(Zoysia sinica, Z. matrella, Z. japonica, Medium-leaf type zoysiagrass(hybrid zoysiagrass)) and bermudagrass(Cynodon dactylon) collected from Korea were used in this study. Total stolon length and the number of stolon per square meter, relative growth rate of shoot and stolon, and coverage rate were analyzed for 2 year. C. dactylon showed not only the most growth response with high relative growth rate of shoot and stolon, which were 19.9% and 66.3%, but also resulted in higher level of turf visual quality compared to others. Whereas Z. japonica showed the least growth response with low relative growth rate of shoot and stolon, which were 2.4% and 0.7%. Although all warm-season turfgrasses took root and grew up well, there were different growth rates between the interspecies. Z. sinica 'Z2034', Z. matrella 'Z4091', Z. japonica 'Z1064', Medium-leaf type zoysiagrass 'ZN6019' and C. dactylon 'BN7014' were the greatest growth rate of shoot and stolon. These results will be useful for selecting salt tolerant breeding lines and also used to develop a turfgrass cultivar with strong salinity tolerance through continuous monitoring.