• Korean Journal of Weed Science
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• v.16 no.4
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• pp.301-308
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• 1996

In this study, a propagation characteristics of green kyllinga(Kyllinga brevifolia var. leiolepsis H.) was investigated. Two to three rhizomes(1st rhizome) arised from the basal part of main shoot at 4th leaf stage and were grown to extend on the soil surface. Then new shoots(lst tillers) emerged from every node of the 1st rhizome. Second rhizomes also arised from the basal part of lst tiller at the time of 4th leaf openning. With such a regularity, 5th rhizomes and about 688 shoots were produced from one plant during one year-cultivation without competition under the natural condition. The degree of vegetative growth and seed formation was 3 times and 2.5 times higher in rhizomeoriginated plant than in that from seed, respectively. The amount of seed formation and the 1000 seeds weight was highest in one planted on June 1 and Aug. 1, respectively. Short-day treatment of less than 14hr appeared to be necessary for the induction of flowering and it was effective as treated not during germination but since at least 2 leaf stage of green kyllinga. Each shoot individually responded to short-day. When plants were exposed to short-day (9hr, day / 15hr, night) treatment at the stage of 2-3 leaves, more than 7 cycles were required for flowering induction. Bolting in main shoot occurred after emergence of 4 leaves under the short-day condition. Exogenous $GA_3$ slightly accelerated the velocity of bolting only in short-day condition.

• Korean Journal of Weed Science
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• v.14 no.3
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• pp.171-175
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• 1994

Physiological changes in Eleocharis kuroguwai Ohwi as affected by bensulfuron-methyl {Methyl 2-[[[[[(4, 6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino] sulfonyl]methyl]benzoate} was determined to relate the characteristics with regrowth behavior. There were no changes in relative growth rate(RGR) during the period of growth cessation after application of bensulfuron-methyl. RGR's of the growth ceseased plants caused at 39 and 51 g/ha began to increase in between 25 and 30 days after application (DAA) and between 30 and 35 DAA, respectively. In untreated plant tuber carbohydrate rapidly decreased right after emergence and almost consumed within 40 days. There was no carbohydrate consumption during the period of growth cessation in bensulfuron-methyl-applied plant, but the content started to rapidly decrease with regrowth. Tuber viability lasted for 30 days in untreated plant, while tubers were viable for 60 and 70 days after application of bensulfuron-methyl at 39 and 51 g/ha, respectively. During the period of growth cessation the plants kept minimum respiration and photosynthesis, but with regrowth respiration and photosynthesis were resumed and rapidly increased.

• Korean Journal of Weed Science
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• v.15 no.3
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• pp.188-196
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• 1995

Blackgrass and water foxtail are troublesome weeds in a cultivation area of cereals. To know whether water foxtail could substitute for blackgrass as a plant material of screening for the discovery and development of new cereal herbicides, they were compared in a greenhouse and a growth chamber with respect to initial growth characteristics and responses to various herbicides. Blackgrass had a higher germination rate at lower temperature and a higher growth rate at higher temperature as compared to water foxtail. In addition, blackgrass was less sensitive to long day than water foxtail. These results suggest that blackgrass grows better in a cultivation area in spring than water foxtail. As compared to water foxtail, blackgrass showed shightly susceptible responses to herbicides when they were applied to soil surface at one day after seeding. However, the responses to the herbicides of blackgrass and water foxtail were similar with a foliar application of the herbicides at 3 or 4 leaf stage of the plant. Since there were no considerable differences in the herbicidal responses of the two plant species, water foxtail could substitute for blackgrass as a plant material for a primary herbicide screening. When water foxtail was used in a post-emergence screening test, seeding amount of 0.1g/$350cm^2$ and postemergence application of herbicides at 3 to 5 leaf stage were found to be appropriate on the view of alleviating screening efforts in a greenhouse.

• Korean Journal of Weed Science
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• v.13 no.1
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• pp.14-18
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• 1993

Greenhouse study was undertaken to find tank-mix feasibility of quinclorac with molinate and propanil, selective post-emergence herbicides in controlling barnyardgrass, for reducing the application rate of quinclorac. Following foliar application in combination of quinclorac at 0.038, 0.075, 0.150, and 0.300kg ai/ha with molinate at 0.190, 0.380, 0.750 and 1.500kg ai/ha, and propanil at 0.263, 0.525, 1.050, and 2.100kg ai/ha at 3.5-leaf stage of barnyardgrass, fresh weight and weeding efficacy and their interaction by Colby's efficacy method were evaluated. Percent inhibition of barnyardgrass growth by quinclorac, molinate and propanil at recommended rate were 78.1, 26.1, and 61.7%, respectively. The dose combination shown above 85% in weeding efficacy were from 0.300kg of quinclorac with 0.75kg of molinate and 0.150kg of quinclorac with all rates of propanil. Therefore, combination of quinclorac with molinate tended to additive interaction and that of quinclorac with propanil appeared partially synergistic interaction. Conclusively, for reducing the application rate of quinclorac, the combination of quinclorac with propanil was more synergistic than that of quinclorac with molinate.

• Weed & Turfgrass Science
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• v.5 no.3
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• pp.111-125
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• 2016

Cordgrass (Spartina spp.) is recognized as a highly invasive plant in estuaries throughout the world because of remarkable versatility and resiliency, significant reproduction, strong adaptability, rapid spreading, and vigorous growth. In this review, therefore, to provide insights on the effective management practices, the previous research works were summarized and discussed. Spartina spp. is a perennial halophyte, warm-season (C4) grass that reproduces both sexually through seeds and asexually by rhizomes. Management strategies for cordgrass have included various physical, biological, and chemical controls. Herbicides are usually the most cost-effective means of control. Currently, glyphosate, imazapyr, fluazifop and haloxyfop have been practically used. To improve the control efficacy, a combination of two more than methods (example, mowing-spraying) is needed to be applied consistently every year for at least 3 to 4 years and to be sprayed with enough dry time (>4-6 hr) at an early growth stage (before flowering). Consistently repeated application of same herbicide have to be avoided to prevent an unexpected emergence of herbicide-resistant lines. On the other hand, Spartina spp. have many positive functions for agricultural and eco-engineering purposes. Thus, we have to give more intensive research for effectively managing advantages and disadvantages of Spartina plantations.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.3
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• pp.216-219
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• 2000

A field study was carried out to compare the performances of mulching with recycled paper, oil-treated paper and urea-coated paper in spring season potato culture. Soil temperature, weed occurrence, and the growth and yield of potato (cv. Sumi) were compared with unmulched control. The average soil temperatures at 5cm soil depth during the first 10 days after planting were 18.9$^{\circ}C$, under paper mulch and 20.6$^{\circ}C$, under oil-treated paper mulch, being lower 0.8$^{\circ}C$ and higher 1.2$^{\circ}C$, respectively, than unmulched control. Paper mulch lowered maximum soil temperature by 4.6$^{\circ}C$, on a fine day, while oil-treated paper mulch elevated it by over 6.6$^{\circ}C$, Urea-coated paper was decomposed fester than the mulch paper without urea coating. The former was decomposed 50% by 80days after mulching, but the later only 20%. In all mulch treatments, weeds were effectively controled throughout the potato growing season. The percent emergence of potato was not different significantly among treatments. However, a little lower emergence and poor early growth were observed under oil-treated paper mulch because of higher soil temperature. Except oil-treated paper mulch, the paper mulches with and without urea coating showed no difference in growth and yield of potato from the unmulched control. The growth and yield performances were poorest under oil-treated paper mulch. Oil-treated paper mulch would result in difference growth and yield performances if potato is planted earlier than April IS in the present experiment. Further researches are needed for this aspect.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.3
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• pp.260-269
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• 1986

This experiment was conducted to investigate the effect of mulching materials on the emergence rate, root dry weight and grain weight of sesame using variety Poong Nyun Ggae and also their effects on physical properties of soil, evapotranspiration and weed growth on the respective plots were studied. The effect of soil water holding capacity at mulching with polyethylene film and straw increased 5.4%, 2.8% to non-mulched plot respectively. The maximum soil temperature was raised up to 4$^{\circ}C$ by applying clear film and was dropped down to 7$^{\circ}C$ by straw. The minimum soil temperature was raised up to 2$^{\circ}C$ by clear film and was dropped down to 3$^{\circ}C$ by straw. In the early stage, the soil physical properties of clear film mulching were better than those of non mulching, and so was in emergence rate. In the late stage, soil strength was high at non mulching, and soil porosity, soil aeration and water infiltration rate were high at film and straw mulchings. Total root dry weight was great at clear film mulching, and root dry weight was concentrated mainly in the upper 10 cm of soil profile. The amount of weeds collected was the least at black film mulching. There were of little difference in evapotranspiration among treatments. The grain yield of sesame was increased to 57% by polyethylene film and 25% by straw mulching.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.2
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• pp.155-158
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• 1999

Alfalfa grows wild in some parts of Korea, but specific information is lacking as to its growth characteristics, nutritive value and dry matter yeild. The objective of this study was to evaluate the usefulness of wild alfalfa(Medicago sativa L.) as a forage. Wild alfalfa and 'Vernal' were field sown at Keongsan, Keongbuk in the spring of 1995. Emergence for 'Vernal' was better than for wild alfalfa. It was observed that the flowering date of the wild alfalfa was delayed by 8 days. Regrowth of 'Vernal' was better than that of the wild alfalfa at each harvesting. After the last harvesting date, September 22, there was poor regrowth of the wild alfalfa, but regrowth of 'Vernal' was moderately vigorous growth. Weed infestation in the wild alfalfa plots was higher than in the 'Vernal' plots. Thle dry matter yields per hectare were significantly(P<0.05) higher for 'Vernal' than for the wild alfalfa. The CP content was slightly higher in the wild alfalfa in comparison to 'Vernal'. NDF and ADF contents were lower in the third cut, but they were not different in the 1st and 2nd cuttings.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.512-518
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• 1994

One of most laborious work in rice farming is transplanting of rice seedling which has been required preparation of nursury bed and care of seedling during one month period. In this research, direct seeding in dry paddy(DS) was practiced to compare with traditional tansplanting(TP) in Suwon and Milyang. Growth stages in DS were delayed as its planting time was about 36 days later than TP. Heading stage of DS at Suwon was delayed about 15 days as compared to transplanting culture. Rice yield in DS was decreased 8.2%(Suwon) and 0.11%(Milyang), repectively. Working-hour saving in DS was about 34.0%(Suwon) and 54.0%(Milyang). Production cost of DS was decreased 19%(Suwon) and 29% (Milyang), repectively. Amount of rice production per a unit working-hour in DS could incresed 37%(Suwon) and 113%(Milyang) compared to that of TP, respectively. Therefore, DS was decreased little in rice yield, but it could save working hour and production cost, significantly. Warm region like Milyang had more advantage in DS than Suwon. But, DS needs varietal selection for better emergence in low temperature, and more research in weed control and water management.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.977-986
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• 1996

The uncertainty of rains at the onset of wet season (WS) and the drought risk involved hinder growing more than one rainfed lwoland rice crop per year. Establishing transplanted rice well into the WS leaves insufficient moisture in the soil for subsequent crop. Rice establishment early in the season gives the farmer better opportunities to grow a crop after rice. An experiment was conducted startign in 1993 to evaluate dry seeding of rice through slit soil seeding. It is done utilizing the vertical metering slit seeder for conserving soil moisture coming from the first rains in the early WS to sustain germination and establishment of the seeding at least until the succeeding rains under therainfed lowland (RL) environment. The treatment consisted of slit-seeding the PSBRc 14 into the tilled and nontilled plots at 100kg/ha and at depths of <10 mm (shallow seeding) and 60-70m (deep seeding). The control treatment was broadcast seeded on tilled soil and harrow to cover the seeds The superior crop establishment observed in 1995 WS experiment on nontilled, slit-seeded plots confirmed the results observed in 1993 WS and 1994 WS experiments. Emergence in deep seeding was not significantly different from shallow seeding in nontilled plots giving an average yield of 2.1 t/ha in all slit-seeded plots. This offers an advantage of reduced energy in put in nontilled shallow seeding. However, heavy weed infestation has to be addressed at the early stage of rice in nontilled soil to get the full advantage from slit seeding. The consistently better crop establishment observed in slit seeding over that of broadcast seeding in the WS of 1993, 1994 and 1995 also demonstrates that the slit seeding technology can be adopted with confidence in the rainfed lowland field condition to reduce the risks involved in broadcast seeding.