• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.3
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• pp.12-19
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• 2008

This study was conducted to investigate the draft data for the habitat environment and massive propagation method of Miscanthus changii, which is classified as rare species. The in-site analysis of the native soil give a indication of pH 5.24~5.48, electric conductivity (EC)0.03~0.02 $dS{\cdot}m^{-1}$, organic matter (OM) 1.13~1.15%, Ca 3.4 $mg{\cdot}kg^{-1}$, K 0.25 $mg{\cdot}kg^{-1}$, Mg 0.53 $mg{\cdot}kg^{-1}$, N 0.23%, P 2.15 $mg{\cdot}kg^{-1}$ showed low and 0.33~9.12 $cmol{\cdot}kg^{-1}$ CEC. Growth and tiller number in rhizome propagation of Miscanthus changii showed that horticulture media (perlite 1+vermiculate 1+peat moss 1) is the most suitable soil to habitat. As for seed propagation, germination percentage is 0% (0/20) at first seeding, 2% (1/50) at second seeding and 2.1% (6/280) at third seeding. The average germination percentage was below 2%. This is the reason why Miscanthus changi disappear at habitat of poor soil environment and low germination. We gained 61 plants that 60 rhizome propagation and 1 by seed propagation, renatural to habitat.

• Korean Journal of Materials Research
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• v.17 no.1
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• pp.18-24
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• 2007

Mullite-PSZ composite was prepared by sol-gel method using $Al(sec-OC_4H_9)_3,\;Si(OC_2H_5)_4,\;ZrOCl_2\;8H_2O\;and\;Y_2O_3$. The sinterability ana mechanical properties of powder compacts sintered at $1,650^{\circ}C$ for 4 hrs were investigated for various PSZ contents. In result Al-Si spinel formed at $980^{\circ}C$ from amorphous dried gel, and zirconia as well as mullite crystal formed above $1,200^{\circ}C$. The sintered body was densified to $97{\sim}98%$ except the specimen containing 25vol% PSZ which showed the relative density of about 95% obtained by sintering at $1,650^{\circ}C$ for 4 h. The flexural strength of the sintered body was a maximum value of 290 MPa in 20 vol% PSZ, which was also considerably larger than the value of 200 MPa without PSZ. The value of the fracture toughness increased linearly with increase of PSZ content and showed a maximum value of $4.3MPam^{1/2}$ in 25 vol% PSZ, Namely this value was remarkably larger than the $value(2.6MPam^{1/2})$ of pure mullite without PSZ.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.132-139
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• 2010

To manage the effluent nutrients amounts from rice paddy fields using free range ducks or rice bran, we evaluated the effects of a purifying paddy field which is no fertilizer, no pesticides, and dense rice seedling having a concept of constructed wetland. The experimental paddy field was located at downstream in the watershed of ducks using rice culture area in Milyang. The purifying paddy of land design were treated with seeding method, and vegetation type. As land design, direct seeding on plane, and direct seeding on high-ridge field in 2007. Planting rice only, and planting rice with water hyacinth were treated as vegetation type in purifying paddy in 2008. The purifying paddy fields were effective to reduce amount of T-N and T-P contents in effluent to 33.2~45.3%, and 53.1~55.4%, respectively. The direct seeding on high-ridge treatment, having long residence time of effluent water was more effective than plane plot as T-N 0.29 $g^{-1}m^{-2}d^{-1}$, and T-P 0.031 $g^{-1}m^{-2}d^{-1}$. The planting rice with water hyacinth treatment was effective than planting rice only as T-N 0.23 $g^{-1}m^{-2}d^{-1}$, and T-P 0.049 $g^{-1}m^{-2}d^{-1}$. The optimum area of purifying paddy field to treats all effluent were found out 3.2~4.7% of rice culture area using free range ducks, and rice bran at upper stream.

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.99-104
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• 1995

This experiment was conducted to evaluate effective weed control in direct-seeded rice under dry fields. The results obtained are as follows. Cyhalofop/bentazone EW and cyhalofop/pendimethalin EC were very effective for the weed control but cyhalofop/cinosulfuron WP and cyhalofop/azimsulfuron SC were tended to exhibit the lower weeding effect. The plant height and the tiller number of rice were not greatly affected by herbicides, but rice yield was greatly influenced by them. The control efficacy was observed the extend of 94% until 60days after seeding under the treatment of systematic herbicides such as foliar applied pendimethalin propanil EC at 15days after seeding mowed by pyrazosulfuron molinate GR at 5days after irrigation. Irrigation at 25days after seeding was able to control annual weeds by the extent of 25% and exhibited control effect of 94% on systematic treatment of herbicides compared with that of 35days after seeding.

• Korean Journal of Weed Science
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• v.17 no.2
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• pp.139-146
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• 1997

The experiment was conducted at Gyeongbuk Provincial Rural Development Administration in 1996 to obtain basic information on weed ecology and effective weed control in direct-seeded rice fields under different seeding types and seeding times. A large number of upland weeds such as Echinochloa crus-galli, Digitaria sanguinalis, Capsella bursa-pastoris and Stetaria viridis etc occurred at early growth stage, while Eleocharis kuroguwai, Aneilema keisak and Cyperus serotinus dominated at late stage in dry seeded rice field. In wet seeded rice field, the dominance of E. crus-galli was lower and the occurrence of M. vaginalis and A. keisak were higher than in dry seeded field. Amount of weed occurrence in dry seeded field was 1.8 to 2.4 times greater than in wet seeded field and it increased with delaying seeding time. Increasing rate of weed occurrence through whole life cycle was the highest at 20 days after seeding (DAS) to 40 DAS, regardless of seeding types and seeding times. Simpson index in wet seeded field was higher than in dry seeded field and it gradually increased as growing of dominant species. For F-value test, it was recognized as statistical significant in seeding types, seeding times and interaction of two factors.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.3
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• pp.238-246
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• 1994

This experiment was carried out to determine the effects of seeding date and fall harvest method on the growth characteristics, forage yield and quality of winter rye(Seca1e cereale L.) at the forage experimental field, College of Agriculture and Life Sciences, SNU, Suweon from 5 September 1992 to 21 May 1993. The experiment was arranged in a split plot design with three replications. Main plots consisted of three harvests, no defoliation, cutting and grazing. Sub-plots consisted of seeding dates, early(5 September), mid(25 September) and late(l0 October). The results obtained are summari7d as follows; I . A 3-day difference in the first heading of rye was observed between no defoliation and fall grazing, while there was a 6day difference between early and late seeding dates. Therefore, the effect of seeding dates on the fist heading date of rye was larger than that of fall harvest methods. 2. CP content of rye with fall grazing was slightly higher averaged 16.5% compared with both fall cutting and no defoliated 1ye(15.6%). Mean CP content of rye at the early, mid and late seeding dates was 14.2, 14.5 and 19.1 %, respectively. 3. ADF content of rye was slightly higher with both fall cutting(29.99) and no defoliation(29.5%) than that of fall grazing(28.0%). ADF content of rye at the early, mid and late seeding dates was 30.7, 29.1 and 27.7%, respectively. Effect of fall harvest methods and seeding dates on NDF content of rye were similar to the observations made on ADF. 4. RFV and IVDMD of rye were lower with both no defoliation and fall cutting than fall grazing. but those of rye slightly increased with seeding dates progressed. 5. Dry matter yield of rye was the highest of 6,779 kg/ha with fall cutting, while the lowest yield of 6,240 kg/ha was obtained from no defoliation But no significant difference was found among the harvest methods. Dry matter yield of rye was significantly declined with later seedings. It is concluded that the highest forage yield of rye be possible from two harvest systems of fall and spring with earlier seeding rather than from one harvest system of spring.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.1
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• pp.1-8
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• 1996

The objective of this study is to obtain the basic data for investigating the effects of organic reserves on winter survial or regrowth yield. Forage rape (Brussicu napus L.) was sown at 10 day> interval from Sep. I to Nov. 1. Field-grown palnts were sampled on the before wintering (Dec. 4) and on the wintering period (Jan. 16) to analyze the nitrogen and non-structural cahohydrate reserves. The rate of winter survival and regrowth yield were also measured in the spring of next year. On the before wintering, the dry matter yields from the plots sown on Sep. 1, Sep.11 and Sep. 21 were 860, 596 and 260 kg/lOa, respectively. No. harvest was canied out on the plots sown after Oct. 1 because the growth state was not enough to cut. Both of nitrogen and starch contents per plant significantly increased as the seeding date was later. On the wintering period, the contents of nitrogen reserves in roots were 176.8. 120.1, 71.7, 84.0, 72.1, 45.3 and 33.3 mg/plant, those of starch reserves were 199.0. 55.8, 21.8, 92.6, 86.5, 36.4 and 29.0 mglplant, resepctively, in the plots sown on Sep. 1, Sep. 11, Sep. 21, Oct. I, Oct. 11, Oct. 21 and Nov. 1. The rates of winter survival were 40, 36, 33, 85, 87, 59 and 49% and regrowth yields were 161, 86, 65, 520, 451, 121 and 33 kgD.M/lOa, respectively, in each plots. 'Ihese results clearly showed that seeding date has a close influence on the level of organic reserves and forage yield, and that the possibility of continuous utilization on the before and alter wintering is extremely limited by seeding date.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.23-27
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• 1988

This experiment was conducted to determine germination ability, life cycle, regrowth ability of Portulaca oleracea L. The newly harvested seeds from P. oleracea flowered before July 15 were able to germinate, but percent germination decreased markedly as the flowering time was later than July 15, showing no germination of seed collected at Sept. 12 which were flowered at August 30, 76.5% of seeds can be germinated in the light as seed stored in room condition for 90 days, but in dark condition, it needed 2 years of seed storage for germination. Low temperature treatment at $2^{\circ}C$ for 5 days enhanced seed germination of P. oleracea in both light and dark conditions. The maximum vagetative growth was observed at 30 to 75 days after seeding. The late seeding time such as July 1 shortened the period of vegetative growth. However, regardless of the seeding times, the first flowering was observed at about 40 days after seeding. Leaf numbers, shoot lengths, fresh and dry weights were greatly affected by the seeding dates, showing that the earlier seedings produced significantly higher shoot length, fresh and dry weight, leaf numbers and branch numbers than those of the late seedings. When all branches were removed on 68 days after seeding, their regrowth ability was 50.3% and cuttaged branches showed 78.1% regrowth as compared to intact plant.

• Journal of Ginseng Research
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• v.22 no.4
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• pp.229-236
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• 1998

The incidence of fungi and their possible contribution to low vigour were examined in a collection of ginseng (Panax quiquefolius) seed from Ontario. When examined after one winter of stratification in the field and storage at 4f for five months in the laboratory, the collection exhibited low vigour (plant stand 16.7% of seeding rate six weeks after seeding) and high incidence (94%) of discolored or soft seed. Fungi isolated (and incidence) from 1,304 endosperm halves recovered from surface-sterilized seed were, in order of abundance, Fusarium rostrum (22.2%), Chaetomium crispuum (14.3%), Funriud oxysporum (9.0%), Fusarium sdani (9.0%), iwmor sp. (8.4%), Alternaria sp. (8.1%), Zowieua lucotricha (7.8%), Cylindruarpn sp. (0.9%), Fusarium avenacmm (0.9%), and Vdudla iliata (0.4%). Most of these fungi, including known and potential pathogens of ginseng (species of Alerraria, Cylindrocarpon, Fusarium, and Trichodirma), were associated with both healthy and diseased seed. Application of Benlate (benomyl), Thiram (thiram), or UBI-2584 (tebuconazole) to seed caused slight to pronounced reduction in emergence and did not significantly affect plant stand six weeks after seeding. The study demonstrated the high level of infection by fungi, including known and potential pathogens of the cry, in an arbitrary collection of ginseng seed from commercial sources, and the phytotoxicity of the fungicides tested when applied to moist stratified seed. The lack of efficacy of the fungicides precluded determination of the contribution of seedborne fungi to low vigour of the seed.

• Korean Journal of Weed Science
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• v.18 no.3
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• pp.179-185
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• 1998

This study was conducted to investigate changes in weed occurrence and dominance as affected by seeding dates in water seeded rice paddy under field following two years of no-tillage condition. The pre-emergence weeds in no-tillage paddy were controlled by glyphosate application at 7 days before seeding. The rice seeds were seeded on April 20, May 10 and May 30, respectively with 40kg/ha of seeding rate. The weed species in the paddy occurred included three species (Echinochloa cursgalli, Aneilma keisak, Ottelia alismoides) of annual weed, one species (Alopecurus aequalis) of biennial weed and five species (Eleocharis kuroguwai, Leersia japonica, Sagittaria pygmaea, Sagittaria trifolia, Potamogeton distinctus) of perennial weed respectively. Aneilma keisak was found to be dorminant on April 20 and May 10 but Eleocharis kuroguwai on May 30 based on number of weeds. The number and dry weight of weeds occurred were higher on May 10 as compared to in other seeding dates, while proportion of perennial weeds increased as the seeding date was delayed. In particular, weed dorminance varied marketly with seeding date. The Simpson's indices were 0.736 on April 20, 0.261 on May 10 and 0.281 on May 30, respectively.