• Weed & Turfgrass Science
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• v.2 no.4
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• pp.402-407
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• 2013

Bermudagrass (Cynodon dactylon.) is one of the most difficult weedy species to control in turfgrass because it's high tolerant to various environmental and management stresses. This experiment was performed to find the integrated weed management including cultural practices to suppress bermudagrass in Zoysiagrass matrella (L) Merr. As results, two sequential applications of Fluazifop-P-butyl 0.05 ml $m^{-2}$ + Triclopyr-TEA 0.5 ml $m^{-2}$ and Fenoxaprop-P-ethyl 0.1 ml $m^{-2}$ + Triclopyr-TEA 0.5 ml $m^{-2}$ applied on 20 days intervals were evaluated the primary option for bermudagrass suppression and turfgrass injury was acceptable in zoysiagrass. In both treatments, turf injury was observed during 30days after the first application and almost recovered at 40days. While Fenoxaprop-Pethyl 0.1 ml $m^{-2}$ + Triclopyr-TEA 0.5 ml $m^{-22}$ were lightly phytotoxic to zoysiagrass in chlorophyll content test, there was no growth inhibition of zoysiagrass. Verticut practice (4 mm depth) just before herbicides application where zoyisagrass is contaminated with bermudagrass was not helpful to reduce turf injury in this experiment. However, alone verticut management was utilized to decrease about 12-14% bermudagrass population. Thus the application of Fenoxaprop-P-ethyl 0.1 ml $m^{-2}$ + Triclopyr-TEA 0.5 ml $m^{-2}$ which are permitted for turfgrass after zoysiagrass is perfectly recovered from turf injury by verticut practice should be utilized for bermudagrass reduction in zoysiagrass.

• Journal of Bio-Environment Control
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• v.15 no.2
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• pp.184-189
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• 2006

Effects of interspace mulching between polyethylene film house on growth and quality of oriental melon were followed. Soil moisture in control was 26.0%. Those of black nonwoven fabrics sheet and black film were less 1.2% and 2.9% than control, respectively. Soil temperature in control plot was $2.4^{\circ}$ Those of black nonwoven fabrics sheet and black film were higher $0.8^{\circ}$ and $1.8^{\circ}$ than control, respectively. Black film was better than control in stem length, leaf number and area, chlorophyll content, xylem exudate, first flowering and fruit riping periods. Black film was better in fruit weight and soluble solid, and lesser in fermented and malformed fruit ratios, and increased 28% in marketable fruit ratio to control, 1,864kg. This results were mainly from vinyl coverage between polyethylene film house to intercept rainfall and to increase soil temperature, which fasted growth of roots after transplanting in winter season.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.2
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• pp.166-172
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• 1997

This experiment was carried out to clarify the effect of the deep water irrigation on dry-seeded rice cultivation at the three different water managements-deep continuous flooding(DCF), water saving irrigation(WSI), ordinary irrigation(OI). The highest tillering numbers per $m^2$ of rice were 551, 466 and 455 in OI, WSI and DCF, respectively. The tillering number of rice plants were significantly reduced in DCF. Heading date was delayed and the total chlorophyll content in leaf after heading was higher in DCF than those in other irrigation methods. For the characteristics associated with lodging, the culm length in DCF was slightly elongated and the diameter of culm in DCF was thicker than that in WSI and OI. The breaking weight and bending moment in DCF also were higher than those in others. As the result, although the culm length in DCF was long, the lodging index was comparatively low. The panicle length in DCF was longer than in OI and WSI. The spikelet number per $m^2$ and 1,000-grain weight were the most in WSI, while panicle number, ripened grain ratio and grain weight were not significantly different. Longer panicle length and more spikelet number resulted in higher yielding capacity in DCF.

• Current Research on Agriculture and Life Sciences
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• v.14
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• pp.67-75
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• 1996

Capsicum annuum 'Nokkwang' plug seedlings were treated with 9 different day and night temperatures to investigate on growth and differentiation in controlled environment conditions. The plant height was the most affected by day temperature and DIF and stem length was the similler results as plant height. However, Leaf unfolding rate and leaf length and width increased as average daily temperature increased. and especially fresh weight was worst at ADT was $15^{\circ}C$ and increased as ADT increased. In contrast with fresh weight, chlorophyll content calculated highest when ADT was $15^{\circ}C$, and decreased as NT increased respectively. The stem lengths were not significantly different among treatments with exception of DT/NT=15/$15^{\circ}C$ which significantly decreased. The ultimate +DIF condition, DT/NT=30/$15^{\circ}C$, caused high T/R ratio due to abundant top growth. It is concluded that DT is $22.5^{\circ}C$, and NT is ranged from $15^{\circ}C$ to $22.5^{\circ}C$ to be produced short, healthy plug seedlings in Capsicum annuum 'Nokkwang'.

• Korean Journal of Environmental Agriculture
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• v.29 no.1
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• pp.12-19
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• 2010

Optimum nitrogen fertigation level by soil testing was determined on the growth and yield of eleven-year-old 'Campbell Early' (Vitis labrusca L.) grapevine in a sandy loam soil from 2005 to 2007. Fifty percent of the annual application of the nitrogen rate (195 kg/ha/yr) was top-dressed as basal fertilizer in all treatments, and the remainders were drip-irrigated with fertigation rate at 25 (12.5% of total N, N 1/4 level of the remainder), 50 (25% of total N, N 1/2 level), and 100 mg/L (50% of total N, N 1 level) in intervals of twice (2.1 mm/times) a week for 12 weeks, and the effect of N drip fertigation was compared to control which the N remainder was applied with surface application as an additional fertilizer. The results showed that chlorophyll content reading in SPAD value and N contents of leaves increased as nitrogen fertigation level increased. Also observed was the growth of the internode and stem diameter of shoots which were longest at N 1/2 level among the treatments conducted both in 2005 and 2006. It was also noted that yield of the fruit was different every year, where average yield for three years was recorded highest in N 1/4 level, and lowest in N 1 level compared to control(surface application). Soluble solid content and titratable acidity of fruit juice were also not significant during the treatments, the maturation of fruits tended to be retarded in N 1 level. The study proved that N 1/4 (N 25 mg/L) levels of fertigation based on soil testing was most efficient in obtaining optimum yield and also, fertigation of grapevine at open field condition reduces the use of nitrogen fertilizer.

• Korean journal of applied entomology
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• v.47 no.3
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• pp.237-248
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• 2008

Development of T. urticae was studied on the leaves of eggplant grown in hydroponics with nitrogen contents of 5 mM, 10 mM, 30 mM, and 60 mM. As the nitrogen level in hydroponics increased, it also increased in the plant whereas that of K, Ca, and Mg decreased. More nitrogen in hydroponics resulted in increased contents of water and crude protein, and decreased ash, carbohydrates, and fibers within the plant. Biomass was the heaviest as 989.5 g at 10 mM and the lightest at 60 mM. Leaf thickness and the content of chlorophyll increased as the content of nitrogen increased. Laboratory leaf disc tests obtained from plants grown at various nitrogen levels revealed that feeding and oviposition preferences of T. urticae were high at 30 mM and low at 5 mM. Ratio of damaged leaf by naturally occurring T. urticae on eggplants of 99 days post-transplant in the greenhouse was the highest as 98% at 60 mM. Degrees of damage on eggplants with and without T. urticae infestation turned up more as the differences in the levels of nitrogen in the hydroponics get bigger. No definite differences in the rate of T. urticae development was found between nitrogen treatment levels but, mortalities in immature stages dropped as the nitrogen levels went up. Adult longevity was the longest of 11.9 for female and 6.9 days for male at 60 mM. Oviposition period was also the longest as 11.7 days at 60 mM and shortened as the level of nitrogen decreased. The number of eggs oviposited was the most as 144.4 at 60 mM while it was the least as 41.0 at 5 mM. Sex ratio was 0.75 in favor of female at 10 mM. $R_o$ and T increased, no trends were detected in $r_m\;and\;{\lambda}$, while Dt decreased as the levels of nitrogen went up.

• Applied Biological Chemistry
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• v.40 no.5
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• pp.416-421
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• 1997

Physicochemical properties of six cultivars of Cheju citrus fruits were investigated according to the harvest date. The fruit index of Citrus. unshiu Marc. var. miynawa, C. $natsudaidai{\;}H_{AYATA}$ and C. sudachi ranged from 1.14 to 1.38 with oval form. The fruit index of C. grandis OSEECK, C. aurantiun LINN and C. platymamma. Hort. SWINGLE ranged from 0.89 to 1.03 with a round form. The fruit weight showed the heaviest in C. grandis, followed by C. natsudaidai, C. aurantiun, C. unshiu, C. platymamma and C. sudachi. The rate of flesh showed the highest in C. unshiu, followed by C. platymamma, C. nat녀daidai, C. sudachi, C. grandis and C. aurantiun. The ratio of juice showed the highest in C. unshiu, followed by C. sudachi, C. platymamma., C. natsudaidai,, C. grandis, C. aurantiun. C. unshiu and C. platymamma, which showed a possibility to be used as raw materials for juices. The soluble solid and the Brix/acid ratio of all the varieties increased as the fruits ripen. Especially those of C. unshiu and C. platymamma were high(10.39, 7.67) in full ripe compared to other varieties. Acid content of C. natsudaidai, C. aurantiun, C. grandis and C. sudachi was sustained higher than $3{\sim}5%$ from the middle of September to the middle of January, and there was the possibility of manufacturing aromatic products like citrus vinegar. The C. sudachi contained the highest content of vitamin C,77.48 mg/100 g. The correlation between vitamin C extraction and season was insignificant. Rind and color value of all varieties were investigated, and the value of the L, a and b increased as the fruits were ripen. The value of a of rind of C. $natsudaidai{\;}H_{AYATA}$ and C. grandis until the end of November was negative. This means that their color was not presented by November since the chlorophyll was in the rind, unlike the colors of the rind of C. unshiu, C. sudachi and C. platymamma which were completed by that time.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.515-521
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• 1997

Tobacco plant was grown for 40 days hydroponically in nutrient solutions composed of different forms of nitrogen, like NO$_3$$^{[-10]}$ -N, NH$_4$$^{＋}$-N, and a mixed formulation of NO$_3$$^{[-10]}$ -N and NH$_4$$^{＋}$-N. Uptake response, nitrate reductase, and glutamine synthetase activity at growth stage were investigated to understand the basic knowledge of nitrogen metabolism. The better growth of shoot and root was observed in the mixed nutrient solution than NO$_3$$^{[-10]}$ -N or NH$_4$$^{＋}$-N, alone. The plant growth in NH$_4$$^{＋}$-N nutrient solution was poor due to ammonium toxicity. The pH of nutrient solution containing NO$_3$$^{[-10]}$ -N increased up to 40 days after transplanting. But the pH of solution containing NO$_3$$^{[-10]}$ -N decreased drastically to 3.42 at 20 days after transplant. The pH in the mixed formulation dropped to pH 3.64 at 30 days after transplant and showed re-increase. It is assumed that nitrogen of NH$_4$$^{＋}$-N form was taken up preferentially at early stage and NO$_3$$^{[-10]}$ -N form was taken up preferentially at middle stage in the treatment with the mixed solution. The result indicates that the relative proportion of nitrogen forms affected the uptake patterns at each growth stages. The contents of chlorophyll and soluble protein were high with the mixed solution. Total nitrogen content was the highest in NH$_4$$^{＋}$-N solution and the content also increased by the application of the mixed type of nitrogen. The amount of nitrate in leaves was high in NO$_3$$^{[-10]}$ -N treatment and the amount of ammonium was high in NH$_4$$^{＋}$-N treatment. The activity of nitrate reductase or glutamine synthetase was highest in the leaves grown in mixed nutrient solution than in those with any other single of nitrogen form.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.4
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• pp.232-242
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• 2002

To investigate the effects of arbuscular mycorrhizal (AM) fungus (Glomus intraradices) colonization on drought-stress tolerance, leaf water potential, chlorophyll concentration, P content and carbohydrate composition were examined in perennial ryegrass (Lolium perenne L.) plants exposed to drought-stressed or well-watered conditions. Drought stress significantly decreased leaf water potential, P content and leaf growth. These drought-induced damages were moderated by mycorrhizal colonization. Drought stress decreased the concentration of soluble sugars in shoots. AM plants had a higher foliar soluble sugar than non-AM plants under drought stress condition. Drought stress depressed the accumulation of starch and fructan in shoots, but stimulated in roots. Under drought-stressed condition, starch concentration in roots was higher in non-AM plants than in AM plants. Fructan was the largest pool of carbohydrates, showing the highest initial concentration and the highest net increase for 28 days of treatment. Drought stress slightly decreased fructan concentration in shoots, but remarkably increased in roots. Under drought-stressed condition, fructan concentrations in non-AM and AM shoots at day 28 were 18.7% and 13.3% lower than the corresponding values measured at well-watered plants. However, in the roots, fructan accumulation caused by drought was lessen 13.6% by mycorrhizal colonization. The results obtained suggest that mycorrhizal colonization improves drought tolerance of the host plants by maintaining higher leaf water status and P status, and by retaining more foliar soluble sugars.

• Korean Journal of Ecology and Environment
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• v.37 no.1 s.106
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• pp.1-11
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• 2004

The limnological characteristics of a coastal lagoon were studied in Lake Hyangho, one of a series of brackish lagoons along the eastern coast of Korea. Phytoplankton community structure, physical factors, and chemical factors were surveyed from May 1998 through November 2002 on a two-month interval basis. Temperature, salinity, Secchi disc transparency, TN, TP, organic matter content of sediment, chlorophyll a concentration, dominant phytoplankton species, and phytoplankton cell density were measured. Salinity gradient was formed between the overlying freshwater stream water and the permeated seawater at the bottom. The chemocline was persistent at the depth of 2 ${\sim}$ 5 m that caused discontinuities of salinity, DO, and temperature profiles. The inversion of vertical temperature profiles with higher temperature in deeper layer was observed in early winter. Secchi disc transparency was very low with the range of 0.1 to 1.1m. TP, TN, and Chl. a concentration in the epilimnion was 0.011 ${\sim}$ 0.238 mgP $L^{-l}$, 0.423 ${\sim}$ 2.443 mgN $L^{-l}$, and 0.7 ${\sim}$ 145.2 mg $m^{-3}$, respectively. Sediment was composed of silt and coarse silt. COD, TP, and TN content of dry sediment were 19.7 ${\sim}$ 73.3 mg$O_2\;g^{-1}$, 0.61 ${\sim}$ 1.32 mgP $g^{-l}$ and 0.64 ${\sim}$ 0.88 mgN $g^{-l}$, respectively. Dominant phytoplankton species were chlorophytes (Ankistrodesmus falcatus) and cyanobacteria (Oscillatoria sp. and Merismopedia tennuissima). The total cell density was in the range of 560 ${\sim}$ 35,255 cells $mL^{-l}$.