• Weed & Turfgrass Science
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• v.3 no.4
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• pp.329-335
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• 2014

This study was performed to study characteristics of new zoysiagarass cultivar 'Green Ever' (Plant Variety Protection Application no. 2014 - 02). 'Green Ever' was developed by selection breeding among 100 native zoysiagrasses collected in South Korea. 'Green Ever' showed specific bands (1.48 kb with OPC14 and 1.05 kb with OPD5) which were distinct from 'Anyang Joonggi' or 'Dongrae Koryogi' in RAPD analysis. 'Green Ever' was classified as Z. matrella in morphological evaluations including plant height ($6.8{\pm}0.5cm$), leaf width ($2.0{\pm}0.1mm$), height of lowest leaf ($1.9{\pm}0.1cm$) and seed length ($3.0{\pm}0.1mm$), which was similar with morphological characteristics of 'Dongrae Koryogi'. Turf quality, shoot density and chlorophyll content of 'Green Ever' were higher than them of 'Anyang Joonggi' and 'Dongrae Koryogi' under intensive management such as fairway on golf course, especially shoot densities of 'Green Ever' were excellent higher than 'Anyang Joonggi' and 'Dongrae Koryogi' during experimental periods. It could be extensively used in fairway, teeing ground of golf courses and landscape garden after further study about various environmental adaptabilities such as winter kill, wear tolerance etc.

• Asian Journal of Turfgrass Science
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• v.23 no.1
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• pp.77-90
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• 2009

Near Infrared Reflectance Spectroscopy(NIRS) is a quick, accurate, and non-destructive method to measure multiple nutrient components in plant leaves. This study was to acquire a liner regression equation by evaluating the nutrient contents of 'CY2' creeping bentgrass rapidly and accurately using NIRS. In particular, nitrogen fertility is a primary element to keep maintaining good quality of turfgrass. Nitrogen, moisture, carbohydrate, and starch were assessed and analyzed from 'CY2' creeping bentgrass clippings. A linear regression equation was obtained from accessing NIRS values from NIR spectrophotometer(NIR system, Model XDS, XM-1100 series, FOSS, Sweden) programmed with WinISI III project manager v1.50e and ISIscan(R) (Infrasoft International) and calibrated with laboratory values via chemical analysis from an authorized institute. The equation was formulated as MPLS(modified partial least squares) analyzing laboratory values and mathematically pre-treated spectra. The accuracy of the acquired equation was confirmed with SEP(standard error of prediction), which indicated as correlation coefficient($r^2$) and prediction error of sample unacquainted, followed by the verification of model equation of real values and these monitoring results. As results of monitoring, $r^2$ of nitrogen, moisture, and carbohydrate in 'CY2' creeping bentgrass was 0.840, 0.904, and 0.944, respectively. SEP was 0.066, 1.868, and 0.601, respectively. After outlier treatment, $r^2$ was 0.892, 0.925, and 0.971, while SEP was 0.052, 1.577, and 0.394, respectively, which totally showed a high correlation. However, $r^2$ of starch was 0.464, which appeared a low correlation. Thereof, the verified equation appearing higher $r^2$ of nitrogen, moisture, and carbohydrate showed its higher accuracy of prediction model, which finally could be put into practical use for turf management system.

• Weed & Turfgrass Science
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• v.7 no.2
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• pp.87-97
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• 2018

Turfgrass provides various beneficial effects to our societies such as recreation, aesthetic components, and other public service. Diseases in turfgrass is the major issue, which cause quality problems in golf courses, playgrounds, parks and cultivation areas, and tremendous cost is required to prevent the diseases. Research activity and investigation for turfgrass disease remain to be further attributed when compared to other crops in Korea. In this study, we present previously reported turfgrass diseases researches, especially caused by fungal pathogens, and review the history of turfgrass research activity in Korea to contribute future turfgrass research direction. Research papers were searched and analyzed using Korea Educational and Research Information Service (www.riss.kr). More than eighty papers presented turfgrass diseases and among the papers, 50% were published in Korean Journal of Turfgrass. Half of the papers reported turfgrass diseases control. Research articles about large patch disease were the majority (36%), followed dollar spot (18%), Pythium blight (10%) and Typhular blight (8%). Number of the first disease reports in Korea were total fifteen. Total 542 fungicides have been registered in Korea to prevent turfgrass diseases and most of the fungicides were for brown patch, rust, yellow patch, dollar spot, snow mold, summer patch, anthracnose, Pythium blight, powdery mildew and algae. And we will also need to conduct ecological studies on turf diseases and to develop control methods with improved efficacy and environmentally-friend sound. Researches on epidemiology of turfgrass diseases which deals with the incidence, distribution, and interactions with other factors will be also greatly favored for precise control prescription, timing of control and use of less pesticides.

• 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.

• 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.

• Journal of Plant Biotechnology
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• v.35 no.4
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• pp.245-256
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• 2008

The current legislation in South Korea clearly states that the tolerance threshold on the adventitious presence of GMO in environment-friendly agricultural products is 3.0% and no GM seed should be detected in their planting seed batches. To date, in Korea, there is no approved GM crop for commercial cultivation in field. However, several GM crops including rice, Chinese cabbage, potato and wild turf grass are currently under risk assessment for their environmental release. Also Korean government (Rural Development Administration, RDA) announced that 11 institutes including universities have been currently certified to carry out a risk assessment of GM crops. Meanwhile, the cultivated area and certified quantities of environment-friendly crops (organic, pesticide-free and low-pesticide) are sharply increasing every year according to the report of National Agricultural Products Quality Management Service (NAQS). In detail, in 2007, the certified quantities of environment-friendly agricultural products were elevated up to 100-fold for organic, 171-fold for pesticide-free and 2,324-fold for low-pesticide crops when compared with those in 1999. The total certified quantity of environment-friendly cereal crops in 2007 was equivalent to 6.4% of total production of cereal crops. Moreover, 24% of total production of root and tuber crops such as potato and sweet potato were certified for environment-friendly agricultural products. In these circumstances, I strongly suggest that current legislations on GM crop's safety management should be revised to include strategies for the coexistence of GM with non-GM crops, especially environment-friendly crops before GM crop is approved to be cultivated for commercialization. Since all types of crops are grown in an open environment, the adventitious presence of GM crops among non-GM crops is inevitable if appropriate measures for coexistence are not established for species by species such as isolation distance, workable management measures to minimize admixture.

• Asian Journal of Turfgrass Science
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• v.18 no.1
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• pp.37-46
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• 2004

The purpose of this study is to find the suitable putting green maintenance equipment for improving the quality of putting green. This study was carried out to investigate the green speed(i.e., ball roll distance) by different the types of greens mower(between work-behind greens mower and riding greens mower), the types of reel blades(between 9 blades and II blades) and the types of roller(between riding soil sprayer and lightweight roller). Green speed of golf course putting greens is assessed by use of Stimpmeter. The west course of Lakeside Country Club was selected for the case study. The results are summarized as follows; 1. The green speed was faster in 3.8 mm moving height treatment plot using work-behind greens mower than in 3.8 mm moving height treatment plot using riding greens mower right after the moving and even after eight hours had passed, and it was statistically significant at a 95% confidence level. Therefore, work-behind greens mower was judged to be a proper equipment type for the fast green management practice than riding greens mower. 2. The green speed was faster in 3.2 mm mowing height treatment plot using work-behind greens mower equipped with II blades than in 3.2 mm mowing height treatment plot using work-behind greens mower equipped with 9 blades, and this result was statistically significant at a 95% confidence level. Therefore, II-blade was judged to be a proper blade type for the fast green management practice than 9-blade. 3. The difference in green speed (green speed increased after rolling) between a treatment plot mowed at 3.0 mm mowing height with the work-behind greens mower and then rolled a single time with riding soil sprayer and a treatment plot mowed at 3.0 mm mowing height with the work-behind greens mower and then rolled once with lightweight roller was not statistically significant at a 95% confidence level. However, the difference in green speed (green speed decreased after rolling) between two treatment plots measured after eight hours had passed was statistically significant at a 95% confidence level. Therefore, the lightweight roller was judged to be a proper roller type for the fast green management practice than the riding soil sprayer.

• Asian Journal of Turfgrass Science
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• v.24 no.1
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• pp.45-49
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• 2010

Research on nitrate-nitrogen ($NO_3-N$) leaching in turfgrass indicates that in most cases leaching poses minimal risk to the environment. Although there have been many studies investigating $NO_3-N$ leaching, there has been little research to investigate the effect of compaction level and rootzone mix on nitrogen (N) leaching. The research objective is to determine the effect of compaction level and rootzone mix on nitrogen leaching. The four rootzone mixes are 76.0:24.0, 80.8:19.2, 87.0:13.0 and 93.7:6.3 % (sand:soil). The four levels of compaction energies are 1.6, 3.0, 6.1, and 9.1 J $cm^{-2}$. Nitrogen was applied using urea at a rate of 147 kg $ha^{-1}$ split among three applications. Rootzone was packed into a polyvinylchloride pipe with a perforated bottom to facilitate drainage. Rootzone depth was 30 cm over a 5 cm gravel layer. Each column was sodded with Poa pratensis L. Hoagland solution designed for coolseason grasses, minus N, was used to ensure adequate nutrition in the rootzone. Turf grass quality and clipping yield were recorded from each tube at two-week intervals. The clippings were oven-dried at a temperature of $67^{\circ}C$ for 24 h and weighed. At the end of the study, root dry weight was determined by washing and oven-drying samples at $67^{\circ}C$ for 24 h. Leachate solution was collected weekly for analysis. More than 6.1 J $cm^{-2}$ of compaction energy increased possibilities of surface runoff. The compaction energy between 3.0 and 6.1 J $cm^{-2}$ produced more clipping dry weight and less N leaching than 9.1 J $cm^{-2}$.

• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.331-344
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• 2009

Buffalograss is an important turfgrass species with excellent cold, heat, and drought tolerance. Understanding the physiological integration of buffalograss under heterogeneous conditions helps to develop cultural practices that better use limited resources for uniform turf quality. The objective of this study was to evaluate physiological integration of buffalograss under water deficit stress and the involvement of lipid peroxidation and antioxidants in the process. In one experiment, buffalograss was planted in the center of a four-compartment growth unit. Watering frequencies, once a week(+) and once in two weeks(-), were combined with the sand(S) or peat(P) in each unit to generate five total treatments(P+S-P-S+, P+P+P+P+, S-S-S-S-, P-P-P-P-, and S+S+S+S+). The average number of shoot established from the heterogeneous root-zone medium was higher than the average of four possible homogeneous media. In second experiment, single ramet in Hoagland solution($S_0$) or single ramet in Hoagland solution with 20% PEG-6000($S_s$) were compared with two connectedramets under different treatments. Treatments for connected ramets were young ramet in Hoagland solution($Y_{os}$) and old ramet in Hoagland solution with 20% PEG-6000($O_{os}$), and old ramet in Hoagland solution($O_{ys}$) and young ramet in Hoagland solution with 20% PEG-6000($Y_{ys}$). Lipid peroxidation, antioxidants, and proline showedphysiological integration between ramets subjected to different levels of water stress. Superoxide dismutase(SOD), Guaiacol peroxidase(G-POD), malondialdehyde(MDA), and free proline also showed different time courses and relative activities during the physiological integration.