• 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.22 no.2
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• pp.197-216
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• 2008

Managing a mixture of zoysiagrass with tall fescue has been proposed in transitional zone as a practical practice to combine the advantages of the two species and compensate the limitations. To manage the mixture is a challenge because two species are involved. The objective of this study was to determine if zoysiagrass/tall fescue mixture can be maintained with proper mowing and fertilization under simulated sport traffic at an acceptable quality level. Zoysiagrass was seeded in June and tall fescue was overseeded in August 1996. In November 1996, zoysiagrass coverage was 62.36, 29.88, and 30.02% for 0, 50, and $100\;Kg\;ha^{-l}\;N$ rates, respectively. At the same time, zoysiagrass coverage was 23.53, 41.95, and 57.40% for the mowing heights of 6.5, 5.0, and 3.5 cm, respectively. Zoysiagrass and tall fescue coverage in July 1997 was showing the same trend as in the late season of 1996 although the differences were not as big. There were significant interactions between N fertilization rates and mowing heights. In November 1998, the zoysiagrass coverage was different among the two tall fescue variety mixtures, 21.68, and 32.25% in 'Arid' and 'Grasslands Garland', respectively. Zoysiagrass coverage was favored in lower mowing height, lower N rates, and lower traffic. Interaction effects on zoysiagrass were found between tall fescue variety and nitrogen rate, tall fescue variety and mowing height, and traffic and nitrogen rate. Zoysiagrass shoot density was 7.42, 25.47, and 58.95% for mowing heights of 6.5, 5, and 3.5 cm, respectively; and it was 47.27, 20.27, and 26.26% for N rates of 0, 50, and $100\;Kg\;ha^{-l}\;$, respectively in 1998. The effects on zoysiagrass shoot density from the interaction of N rate and tall fescue variety was significant in 1998. Shoot density responded to the N rate, mowing height, and traffic differently from the ground coverage, indicating that shoot and leaf growth have different adaptation strategies.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.1
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• pp.129-136
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• 2010

This study was initiated to investigate thatch accumulation in several turfgrasses grown under two soil systems. The 45 centimeter deep USGA system was constructed with rootzone, intermediate and drainage layers. The mono-layer system, however, was made with only a 30cm rootzone layer. Turfgrasses used in the study were comprised of 3 varieties from Korean lawngrass of Warm-Season Grass(WSG) and 3 blends and 3 mixtures from Cool-Season Grass(CSG). A total of 9 turfgrass treatments were replicated three times in RCBD in both systems. Cultural practices for the research plot followed a typical maintenance program for highly managed turf. Treatment differences for thatch accumulation were observed among the turfgrasses in both soil systems. Thatch under the USGA system was 9% greater than under the mono-layer system due to its more favorable conditions for turf growth. Higher thatch depth was found with Korean lawngrass, 34~87% in the USGA system and 16~75% in the mono-layer system when compared with CSG. Among WSG, the Joongji variety was the highest in thatch layer under both the USGA and mono-layer systems. Kentucky bluegrass(KB) was the greatest among CSG, since it is a rhizomatous-type in growth habit, resulting in faster production of organic matter over bunch-type of tall fescue and perennial ryegrass. Proper depth in the thatch layer was known to be beneficial by enhancing the resiliency and wear tolerance of the turf in athletic fields. Thus, KB was considered to be a very excellent turfgrass in terms of turf quality, environmental performance, physical properties and soccer player safety. However, disadvantages such as poor water-holding properties, more inclined to injury from environmental stresses and severe diseases and insect injury were also expected where thatch was excessively accumulated. Therefore, these results demonstrate that more frequent measures for controlling thatch such as vertical mowing, topdressing or coring should be employed for soccer fields with Korean lawngrass and KB over other turfgrasses.

• Korean Journal of Weed Science
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• v.32 no.1
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• pp.44-51
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• 2012

This study was conducted to predict the rice yield loss and to determine the economic threshold levels for direct-seeding flooded rice cultivation from competition to the most serious perennial weeds, Cyperus serotinus Rottb. and Echinochloa crus-galli L. The rice yield loss model of C. serotinus and E. crus-galli were predicted as Y = 560 kg/(1+0.001883x), $r^2$=0.933, and Y = 507 kg/(1+0.001734x), $r^2$=0.867, respectively. In comparison of the competitiveness represented by parameter ${\beta}$, it was 0.001883 in C. serotinus and 0.001734 in E. crus-galli, respectively. Economic thresholds calculated using Cousens' equation were negatively related with the competitiveness of weed. The economic thresholds of C. serotinus and E. crus-galli were 15.5 and 2.3 plants per $m^2$, respectively.

• Korean Journal of Weed Science
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• v.10 no.2
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• pp.99-102
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• 1990

Pearl millet (Pennisetum americanum (L.) Leeke) has been found as a promising new forage crop of higher quality and yield in Korea since 1985. The objective of the study was to select preemergence herbicides for weed control in growing pearl millet in order to reduce production cost and with increased yields. Propazine (Milogard 4L) was the best in controlling weeds without its phytotoxicity at the standard application rate, and with the highest survival rate of seedlings of peal millet "Suwon 1" hybrid. Sprayings with Atrazine and Simazine caused lower survival rate of peal millet and with their light phytotoxicity as compared with manual weeding and Propazine spraying. Alachlor killed pearl millet seedlings almost completely. Pendimethalin also was not good for weed control of peal millet due to its severe phytotoxicity and with very low survival rate of pearl millet seedlings.

• Korean Journal of Weed Science
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• v.9 no.3
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• pp.250-261
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• 1989

This study was conducted to evaluate the effect of retardent Paclobutrazol on the seed quality factors such as oil content, protein content and fatty acid composition in peanut cv. Saeddle(early variety) and Napung(medium variety). The results are summarized as follows : Oil content of seed was appeared to increase when Paclobutrazol was applied and especially it was remarkably increased at 120 ppm-90 DAS both in varieties. Even though protein content showed a little increase at 120 ppm-70 DAS in early variety and 120 ppm -90 DAS in medium variety, however, it was decreased in most case. Saturated fatty acids such as palmitic and stearic acid was reduced by Paclobutrazol treatment but unsaturated fatty acids such as oleic, linoleic, eicosenoic and eicosadienoic acid was tended to increase in early variety while palmitic acid was increased in medium variety but linoleic acid reduced and no change was observed in oleic acid content.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.177-182
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• 2010

This environment-friendly study was conducted to investigate the effects of winter barley as cover crop on the suppression of weeds and on the growth of dry direct seeded rice. The present study clarified the effects of winter barley as a cover crop on the weed vegetation, expressed as a multiplied ratio. In cultivation quality of rice, seedling stand was ranged from 104~112 $m^{-2}$. And, seeding stand of barley was the highest seedling stand 634 unit per $m^2$ in April 10 as compared to the other seeding dates. Furthermore, the dry weight of barley seeded in April 10 was heaviest at 146g $m^{-2}$. Rice yield was in 401kg $10a^{-1}$ in the April 10, and 517kg $10a^{-1}$ in the April 30, because of increased weeds caused by a low weed control. Effects of barley cover crop at same seeding with rice was ranged from 77~87% of control. The economic effect of barley as cover crop was analyzed to be increased by low herbicide using, despite of the slight decrease in rice yield during the period.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.15-22
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• 1988

In this experiment, interactions between light and other factors such as chilling, alternating temperature, moisture, content, oxygen, and seed coat which affect germination of Oenothera lamarckiana Ser. seed were investigated to study the physiological effects of light on the germination. Light induced the initial stage of seed germination before radical protrusion by affecting embryo rather than seed coat even under anaerobic condition or low water potential (-18 bars). This light effect on germinability of seed was suppressed by blue light irradiation and the effect was increased with increment of blue light intensity and irradiation time. However, the blue light effect was reversible. Chilling, alternating temperature, softening of seed coat and light showed promotive interaction in the induction of seed germination. Irradiation of filtered light (monochrome), however, reduced chilling effect on germination. Hydrogen-ion concentration and gibberellic acid treatment had no effect on light or dark germination.

• Korean Journal of Weed Science
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• v.32 no.1
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• pp.25-34
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• 2012

Characteristics related to grain quality and physiochemical components such as mineral, total amino acid, free amino acid, and free sugar composition were investigated in Protox inhibitor resistanttransgenic rice (MX, PX, and AP37) and its nontransgenic counterpart (WT). Head rice, palatability, protein, and whiteness (except for MX and AP37) of milled transgenic rice were high or similar to those of the non-transgenic counterpart. Immature rice, unfilled grain, and cracked kernels (PX and AP37) of milled transgenic rice were lower than those of its non-transgenic counterpart. However, there were no significant differences in damaged grain between the transgenic rice lines and its counterpart. Potassium content in PX and copper contents in PX and AP37 were only low compared with their non-transgenic counterparts, but other mineral contents in transgenic rice lines were high or showed no significant differences compared with non-transgenic counterparts. Contents of most total amino acid composition in transgenic rice lines were high or similar to those in non-transgenic counterparts, but the content of isoleucine in AP37 was only low compared with its non-transgenic counterpart. On the other hand, free amino acid, leucine and tyrosine in PX and AP37, and total free amino acid in PX were low compared with their non-transgenic counterparts. However, the content of free amino acid in other kinds in transgenic rice lines were similar to those in their non-transgenic counterparts. Contents of sucrose in MX and PX were low compared with non-transgenic counterpars, but contents of fructose, glucose, and maltose in transgenic rice lines were high or similar compared with their non-transgenic counterparts. This results indicated that Protox genes had no negative affect on the nutritional composition of rice.

• Korean Journal of Weed Science
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• v.11 no.2
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• pp.128-136
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• 1991

This experiment was conducted to evaluate the effect of plant growth regulators, dichlorprop and MCPB on the reduced effect of fruit drop and fruit quality before and after storage in apples. Dichlorprop was tested with dilution of 1000 at 30, 40, 50 days before harvesting, and MCPB with dilution of 4000 at 15, 25, 35 days before harvesting. The results are summarized as follows : Percentage of fruit drop was appeared to the notable reduction as compared with the untreated control when regulators was applied with dilution of 1000 at 30 days before harvesting by dichlorprop and with dilution of 4000 at 35 days before harvesting by MCPB. Degree of fruit colour showed to the remarkable promotion at all the treatment of 30, 40, 50 days before harvesting by dichlorprop as compared with the untreated control. Sugar contents in flesh was increased a little at the treatment of 30 days before harvesting by dichlorprop, but acid contents in flesh was reduced at all the treatment of 30, 40, 50 days before harvesting by dichloroprop and at 15, 25, 35 days before harvesting by MCPB. Passed firmness of fruit after storage was maintained at the treatment with dilution of 4000 at 35 days before harvesting. Therefore, it was repressed a softening of fruit, but by dichlorprop treatment at 30, 40, 50 days before harvesting, fruit firmmess was appeared to reduce according to the passage of storage period. Amount of ethylene evolution after storage was showed to reduce at all the treatment by early treated time of dichoroprop and MCPB, but carbon dioxide increased at treatment conditions such as the front. Accordingly, these relationship showed to be contrary each other.