• Korean Journal of Agricultural Science
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• v.24 no.2
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• pp.126-131
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• 1997

This experiment was conducted to obtain the basic information on ability of germination at low temperature with 26 cultivars of Korea including USA cultivars and to identify the optimal sowing depth in dry-direct seeded rice. Varietal difference in germination rate and days to emergence at low temperature($13^{\circ}C$) was observed. Average germination was 81.2% and range of germination rate showed 64.3 to 94.8%. In days to germination there was varietal difference. Average days to germination was 17.4 days and those range showed 14 to 24days. Negative high correlation was observed between the ability of germination and days to germination. Considering germination and days to germination. Jakwangdo, Nagdongbyeo, Cheongmeongbyeo, Calom, Anjungbyeo, Gyehwabyeo, Daegwanbyeo, Dongjinbyeo and Seohaebyeo were selected as a adaptable cultivar. High correlation was observed among the lodging index and sowing depth, stem diameter, height of central gravity, breaking strength. Seedling emergence was increased and days to emergence was shortened at the seeding depth of 1 and 3cm. Lodging index was decreased as seeding depth was deep and so the reasonable seeding depth would be around 3cm in direct seeded rice.

• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.117-121
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• 2001

This study was carried out to investigate the effects of rice cultivation of no-tillage seeding on the physicochemical properties and rice yield in the paddy soil of Milk vetch (Astragalus sinicus L.) established. The number of Milk vetch establishment was 256 per $m^2$ in the before experiment but 440 per $m^2$ in the after experiment. The seed numbers of Milk vetch were sufficient that Milk vetch seed were not sown again in the next year. Soil physicochemical properties of the plot of Milk vetch cultivation were similar to the conventional plot. The amount of weed occurrence was 87g dry weight per $m^2$ in the conventional but not occurrence in the sowing of Milk vetch establishment. Rice yield was 4.9ton per ha in the conventional and 4.5 ton per ha in the soybean seeder sowing of Milk vetch establishment.

• Korean Journal of Weed Science
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• v.18 no.2
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• pp.154-160
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• 1998

This study was conducted to develop a foliar applied herbicide mixture covering wide spectrum weeds in dry direct seeded rice. Uniform precision central composite design(UPCCD) was employed to evaluate the effect of herbicide mixture among cyhalofop-butyl(cyhalofop), bispyribenzoxim and pyrazosulfuron-ethyl(pyrazosulfuron) having different weed control spectrum and to determine the best application rates of the three herbicide mixtures. The partial additive effect was observed in the mixture of cyhalofop and bispyribenzoxim with pyrazosulfron against Echinochloa crus-galli Beauv var crus-galli L., attributed to the negative interaction between cyhalofop and bispyribenzoxim system. Additive effect was observed in the mixture of bispyribenzoxim and pyrazosulfuron against Cyperus serotinus R. and Aneilema keisak H. but cyhalofop had no effect on these weeds. The most appropriate rate of the mixture of cyhalofop with bispyribenzoxim and pyrazosulfuron was 100 : 12 : 10g ai/ha exhibiting $ED_{90}$ against three weeds such as E. crus-galli, C. serotinus and A. keisak.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.6
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• pp.534-540
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• 1992

Climatic condition and seeding depth affect the seedling stand and early growth in the direct-seeded rice cultivation on dry soil. This experiment was conducted to elucidate the effects of the day /night temperatures and the seeding depths on the seedling emergence and mesocotyl elongation of rice seed. Three combinations of the day/night temperatures(25/2$0^{\circ}C$ 20/15$^{\circ}C$ and 20/1$0^{\circ}C$) were employed with seeding depths 1, 3, 5 and 7cm at the Phytotron of the Crop Experiment Station in 1991. It appeared that seedling emergence ratio increased and days to seedling emergence decreased in the high temperature (25/2$0^{\circ}C$) and the deep seeding depth (5 and 7cm) condition. The seedling emergence ratio did not. show the, difference up . to the seeding depths of 3cm and below, but the ratio decreased from the seeding depths of 5cm and above. Plant height and leaf number were almost the same up to the depths of 3cm at 30 days after seeding, but those of the seeding depths of 5cm and 7cm were remarkably reduced in all temperature combinations. Mesocotyl and lower internode elongation were seen in the high temperature(25/2$0^{\circ}C$) with the seeding depths of 5cm and 7cm. In the seeding depth of 6cm, of the tested varieties, Tamjinbyeo and Odaebyeo showed the highest emergence ratio. Generally, leaves of all tested varieties appeared approximately in the soil depth of 3cm, so the reasonable seeding depth will be around 3cm in the direct-seeded cultivation on dry soil.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.6
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• pp.731-737
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• 1995

This experiment was carried out at National Crop Experiment Station in 1994 to obtain basic information of growth characters and yield of rice under various nitrogen split application methods on different soil textures in direct seeding on dry paddy. Hwaseongbyeo sown on April 27 by flat drill seeding, and irrigation was done at 3 leaf stage after seedling establishment. Number of seedling stand was 159~177 seedlings per $m^2$ regardless of soil texture and nitrogen application method. Number of panicle per unit area in loam was higher than in sandy loam, and it also was higher in top dressing plots, which were 3 times application at rate of 40-30-30% (3rd leaf stage -7th leaf stage -panicle initiation stage) and 4 times application 10-30-30-30%(basal-3rd leaf stage -7th leaf stage -panicle initiation stage), than in conventional method. Leaf colour, leaf area index and dry matter production at heading stage were highest at top dressing plots among the nitrogen application methods in both sandy loam and loam. Lodging index in top dressing plots increased by low breaking weight with long culm. There were field lodging of degree 3 in top dressing plots. Rice yield in sandy loam, loam increased by 7~9%, 6~9% in top dressing of nitrogen, respectively.

• Korean Journal Plant Pathology
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• v.11 no.1
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• pp.94-97
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• 1995

In 1994, an abnormal rice growth was observed in a 0.5-ha scale farmer's field located at Chogye-Myeon, Hapcheon-Gun, Gyeongnam Province where rice cv. Hwayeongbyeo was seeded directly in dry paddy field conditions. The major symptoms were less stands per acreage, short leaf length, and hypertrophy of root tip portion. The disorder was identified as rice seeding bight caused by Rhizopus sp. The average plant stand per m2 in the infested field was 108, while it was 375 in the normal field, and leaf growth was retarded to less than one-third of healthy plant. The average leaf lengths of infected and healthy seedlings were 12.8cm and 38.9cm, respectively. When the infected seedlings were transplanted to pots, flooded-soil conditions developed no new root growth but upland conditions allowed 11.2 new roots emerging. The length of newly emerged root in infested soil was 5.3cm in upland and 7.1cm in intermediate flooding conditions. However, it was 10.9cm in non-infested soil with intermediate flooding conditions. When the plants were matured, the stem length of infected plants was reduced slightly as compared to normal plants, whereas the length of panicle was not significantly different between infected and healthy plants. The number of panicle per plant, however, greatly different with variation of infection degree. Grain quality such as the number of complete and incomplete grains per panicle, the complete grain weight per panicle, and the weight of 1000 grains was not significantly different.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.706-711
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• 1997

Low supply of water is generally the most serious factor limiting rice production. The experiment was conducted to identify the reasonable method for minimum irrigation under ridge direct seeding on dry paddy, at National Honam Agricultural Experiment Station, RDA in 1996. The results showed that the reduction ratio of irrigation water was high in order of furrow irrigation at 15-day>furrow irrigation at 10-day>flooding irrigation at 10-day>, and furrow irrigation at 5-day intervals. However, milled rice yield was high in the furrow irrigation at 5-day intervals and in flooding irrigation at 10-day intervals due to high ripened grain as compared with other treatments indicating two treatments were the most reasonable irrigation methods in terms of saving the labor cost and water supply as well as the admittable yield performance.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.3
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• pp.207-211
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• 1996

This study was conducted in the sandy loam soil to find out the effects of fly ash and zeolite applications on saving of irrigation water which was required great quantities during the cultivation days of dry seeded rice. Total water loss was reduced so rapidly in the early growth stage that n was the least in the 18th day after irrigation. After that day it was increasd due to the growth development and the rising temperature. In the daily mean of decreasing water level during the whole irrigation days, control was 47.7mm but the treatments of fly ash and zeolite were 31.8mm and 35.8mm respectively Amounts of the presumed irrigation water of fly ash and zeolite treatments were lower about 29.1% and 20.9%. respectively than that of control during the whole irrigation days These gaps between control and amendment treatments were greater in the early growth stage than in the late stage Hardness, bulk density and the ratio of solid phase in the soil after experiment were the highest in the fly ash treatment and those of control and zeolite treatments were showed the same trends each other. Amounts of water percoration of control and zeolite treatments in the soil were increased 8.2% and 2.6% respectively in comparision with those in the soil after amendment application, but that of fly ash treatment was decreased 42.5%, In contrast to the water percoration of control in the soil after experiment, those of fly ash and zeolite treatments were decreased 76% and 32%.

• Korean Journal of Weed Science
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• v.3 no.2
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• pp.143-150
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• 1983

Red rice (local name "Sore") as a weed has been a serious threat to rice production in direct-seeded rice culture in Ganghwagun, Gyeonggi province. In the Ganghwagun 508 ha out of 1,420 ha in the Samsanmyeon area is infested with red rice. The average lowland rice yield is about 4,300 kg/ha in the Ganghwagun, but the average upland rice yield is about 2,000 kg/ha in infested area. This study was carried out in order to clarify the ecological characteristics of red rice and factors affecting the competitive ability of five red rice varieties, collected from Samsanmyeon in 1981, with rice cultivar. Five varieties-Monggeunsare, Salsare, Ginkaragsare, Galsaegsalsare, Galsaegkaragsare-showed the same morphological characteristics of cultivated Japonica type, Chuncheongbyeo, but red rice tillers more profusely, is taller and lodges more easily than Chucheongbyeo. It shatters easily about 10-15 days after heading date, and at this time the hull is discolored in yellow or dark brown. There are many types of red rice with short or long owns on the spikelet, occasionally with or without own on the spikelet in the same hill, and the grains are short or long. In red reice leaf blast occurs more severely than in cultivated Indica/Japonica type, Teabaegbyeo, particulary serious in Monggeunsare. When red rice invaded in direct-seeded rice, number of panicles of rice became reduced more than other yield components.