• 한국잡초학회지
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• 제12권3호
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• pp.200-222
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• 1992

The results of recent researches for improvement of seedling stand in direct seeded rice on the dry paddy in Korea were summarized as the following ; a variety to be cultivated should be chosen the characteristics of high percentage germination under low temperature, shorter period of shoot emergence, and better growth of the mesocotyl and shoots. Meanwhile, there was 40% increase in seedling stand at the treatment of removal of the seed awn under using the drill seeder. After seeding the rice seed covered with soil of 3cm depth was better seedling emergence and also there was the hightest seedling emergence at the 70% of moisture content of the soil. In addition, the application of the Release containing GA 10% enabled to increase the seedling stand and furthermore it was effective under deep seeding depth. The optimum seeding date should be seeded around May 10 when mean air temperature is above 12-13$^{\circ}C$ so that may establish more less 70% in seedling stand. Based on an appropriate seedling stand of 150/$m^2$, the optimum seeding rate was 5kg/10a. It was the best in seeding method using drill seeder and the most desirable recommended seeding method was the drill seeder in terms of seedling stand. In order to improve seedling stand water management was more effective in canal irrigation and in drainage at 6hr after irrigation following by the seeding process. On the other hand, for the increase of seedling stand under flooded condition a variety might have characters being better germination at low concentration of dissolved oxygen and vertically deeper growing of the crown root. Also, seedling stand was able to increase with the seed coating of $CaO_2$in the flooded soil. It was possible to be seeded on the early part of May being mean air temperature of avove 10$^{\circ}C$ and the optimum seeding rate was 5kg/10a. For an effective water management water would be flooded up to 3cm depth for 2-3 weeks after seeding. The rice plant grown under the direct seeded cultivation might be not so much strong in lodging resistance compared to that grown under the transplanting and moreover direct seeded rice cultivation under flooded condition would be more weak growth of the rice plant than that on dry paddy. Meanwhile, the lodging would be affected by the seeding rate, the soil depth after seeding. and seeding method even in the same variety. In particular, roots in the lodging pattern of direct seeded rice cultivation under flooded condition were largely distributed on the soil surface so that resulted easily in the lodging. In general, the lodging resistance would be greater as seeding rate and amount of N fertilizer application are lower and soil depth after seeding is higher. Among the introduction of different seeding method the high ridged drill seeding method on dry paddy soil resulted in the lowest in the lodging index and also it was lower in the drill seeding method than in the scattering seeding method under flooded condition. In case of more than 150 seedlings per $m^2$ there was a severe lodging due to high lodging index at the 3rd and 4th internodes. The effective lodging prevention was able to at the treatment of the Inabenfide at 45 days before heading and the Uniconazol at 15 days before heading which caused the shortage by 10-15cm in culm length. Also, fertilizer management using split application of nitrogen would be contributed the reduction of lodging at the rate of 20-30-20-20-10%(basal-5th leaf stage-7th leaf stage-panicle initiation stage-heading stage) on the dry paddy soil.

• 한국작물학회지
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• 제44권3호
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• pp.248-252
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• 1999

This study examined the effects of growth retardants and midsummer drainage on lodging-related characters in direct seeding rice culture on flooded paddy surfaces. Treatments included in this study were continuous flooding, two time midsummer drainages (TTD), and inabenfide or trinexapac-ethyl application after TTD. Culm length was reduced most by 11.4cm in trinexapac-ethyl treatment after TTD, followed by 4.1cm in inabenfide treatment after TTD compared to TTD treatment. A significant reduction in culm length occurred at the 3rd internode in inabenfide treatment applied at 40 days before heading (DBH), while trinexapac-ethyl application at 8 DBH reduced the 3rd>2nd>1st internode. The culm diameter of the 4th internode was increased by the application of trinexapac-ethyl following TTD compared to TTD treatment. Thickness of culm wall was significantly increased by trinexapac-ethyl but not by inabenfide applications. Lodging index was the highest in continuous flooding and the lowest in trinexapac-ethyl treatment after TTD. Subsequently, field lodging did not occur in plots treated by trinexapac-ethyl. Rice plants subjected to midsummer drainage or growth retardants showed higher ripened grain ratio and 1000-grain weight, resulting in higher rice yield. These results indicate that trinexapac-ethyl, which can be applied at the relatively later growth stage after proper judgement of lodging occurrence, could be a useful tool for reducing lodging in direct seeding rice culture on flooded paddy fields.

• 한국작물학회지
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• 제50권1호
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• pp.16-21
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• 2005

This study was conducted to establish the elaborate nitrogen fertilization method to enhance N use efficiency in direct-seeded rice on flooded paddy. The nitrogen uptake by rice plants was insignificant until 25 days after seeding, and increased gradually thereafter. During this early growth stage, rice plants absorbed only the $4\%$ of basal applied N, while the $45\%$ of N fertilizer remained in the paddy soil. The absorption of basal N by rice plants was almost completed at 46 days after application. Nitrogen top-dressed at 5-leaf stage was well matched to crop nutrient demand, so it could be absorbed so actively in 8days after application. As a result, we could cut down the amount of N fertilizer to $36\%$ of the basal N level without significant difference in yield. Plant recoveries of fertilizer $^{15}N$ applied with different application timings were $7.8\%$ for basal, $9.4\%$ for 5-leaf stage, $17.1\%$ for tillering stage, and $23.4\%$ for panicle initiation stage, respectively. When urea was applied with nitrogen fertilization practice based on basal incorporation (BN), plant recovery of $^{15}N$ at harvest was $31.0\%$, which was originated from $13.7\%$ for grain, and $21.3\%$ of the fertilizer $^{15}N$ remained in the soil, and the rest could be uncounted. Plant recovery of fertilizer $^{15}N$ applied with nitrogen fertilization practice based on topdressing at 5-leaf stage (TN), where N rate was reduced by $18\%$ compared with BN, was $35.1\%$ (grain $15.6\%$), and $19.9\%$ of the fertilizer $^{15}N$ remained in the soil, and the rest could be uncounted. TN showed a higher $^{15}N$ recovery than BN because it was to apply N fertilizer at a time to well meet the demand of rice plant direct-seeded on flooded paddy. We concluded that TN would be the nitrogen fertilization method to enhance N use efficiency in direct-seeded rice on flooded paddy.

• 한국잡초학회지
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• 제2권2호
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• pp.141-145
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• 1982

IAA의 종자침지처리(種子浸漬處理)에 의하여 수도(水稻)에 대한 CNP와 Butachlor의 약해(藥害)를 경감(輕減)시킬 수 있는 가능성(可能性)을 검토(檢討)하기 위하여 담수직파(湛水直播)와 건답직파조건(乾畓直播條件)에서 기초실험(基礎實驗)을 수행(遂行)하였다. 1. 담수직파조건(湛水直播條件)에서 IAA 0.1, 1.0, 10.0ppm 에 수도종자(水稻種子)를 침지처리(浸漬處理)하므로써 CNP와 Butachlor에 의한 수도피해(水稻被害)의 경감효과(輕減効果)가 나타남에 따라 수도(水稻)의 초장(草長) 및 건물중(乾物重)은 IAA 무처리(無處理)에 비하여 현저히 증가(增加)되었다. 2. 건답직파조건(乾畓直播條件)에서는 IAA 0.1, 1.0ppm에 수도종자(水稻種子)를 침지처리(浸漬處理)하므로써 수도(水稻)에 대한 CNP와 Butachlor의 피해(被害)는 크게 경감(輕減)되었다. 3. 담수조건(湛水條件)에서 Butachlor를 처리(處理)하거나 건답직파조건(乾畓直播條件)에서 CNP를 처리(處理)한 경우에 IAA의 약해경감효과(藥害輕減効果)는 더욱 현저한 경향(傾向)이었다.

• Weed & Turfgrass Science
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• 제1권4호
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• pp.31-37
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• 2012

담수직파재배에서 사마귀풀과 자귀풀 경합밀도에 따른 벼 수량감소 정도를 예측하고 제초제 사용여부 결정을 위한 경제적 방제수준을 설정하여 저투입, 친환경적인 정밀 잡초관리 체계를 확립하고자 시험을 수행하여 얻어진 결과는 다음과 같다. 쌀수량 감소정도는 사마귀풀의 경우 경합밀도가 $m^2$당 8본일 때 8%, 96본일 때 45% 이었고 자귀풀의 경우 $m^2$당 8본일 때 20%, 96본일 때 77% 이었다. 벼와 잡초의 경합에 따른 쌀수량 예측모델은 사마귀풀의 경우 Y=553.2 kg/(1+0.00913X) $R^2$=0.912 이었고 자귀풀의 경우 Y=567.9 kg/(1+0.04434X) $R^2$=0.961 이었다. 초종별 경제적 방제수준은 사마귀풀의 경우 $m^2$당 3.0본 이었고, 자귀풀의 경우 $m^2$당 0.6본 이었다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1995년도 추계 학술대회지
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• pp.62-63
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• 1995

• 한국작물학회:학술대회논문집
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• 한국작물학회 1995년도 추계 학술대회지
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• pp.60-61
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• 1995

• 한국잡초학회지
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• 제16권4호
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• pp.282-291
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• 1996

벼 담수 표면 산파 재배시 파종시기 및 제초제 처리시기에 따른 잡초 발생 양상과 몇 가지 제초제에 대한 약효 및 약해 반응을 검토한 결과는 다음과 같다. 1. 약해는 두 파종 시기별 모두 파종후 7일>파종후 12일>파종후 17일 처리순으로 나타났고, 특히 bensulfuron methyl+mefenacet+dymron 처리에서 심하였다. 2. 벼의 초기 생육은 파종 시기와 제초제 처리 시기가 빠를수록 억제가 컸다. 3. 잡초 발생 양상은 5월(月) 1일(日) 파종에서는 총 10종으로 화본과 1종, 광엽잡초 6종, 사초과 3종이었으며, 이들 중 대부분이 화본과였고 특히 피가 우점(優点)하였다. 5월 22일 파종에서는 총 7종이 발생하였고 화본과 1종, 광엽잡초 3종, 사초과 3종이었으며 피가 가장 많았다. 4. 공시 제초제의 파종 60일에 잡초 방제 효과는 5 월 1일 파종 구는 파종후 7일에서 17일까지 제초제 처리 시기가 빠를수록 피, 사마귀풀 등 일년생 잡초와 올챙고랭이 및 너도방동사니에 대해서는 높고, 올방개에 대해서는 공시 제초제를 파종후 7, 12일 처리보다 처리 시기가 늦은 17일 처리에서 높았다. 5. 수량(收量)은 파종후 7일 처리에서 약해가 심한 제초제의 처리 구와 파종후 17일 처리에서 방제 효과가 낮은 처리 구에서 유의적으로 감소하였다.

• 한국작물학회지
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• 제44권3호
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• pp.230-235
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• 1999

To study the effects of an urease inhibitor, N-(n-butyl)-thiophosphoric triamide (NBPT), and a nitrification inhibitor, dicyandiamide (DCD), on nitrogen losses and nitrogen use efficiency, urea fertilizer with or without inhibitors and slowrelease fertilizer (synthetic thermoplastic resins coated urea) were applied to direct-seeded flooded rice fields in 1998. In the urea and the urea+DCD treatments, NH$_4$$^{+}$ -N concentrations reached 50 mg N L$^{-1}$ after application. Urea+NBPT and urea+ NBPT+DCD treatments maintained NH$_4$$^{+}$ -N concentrations below 10 mg N L$^{-1}$ in the floodwater, while the slow-release fertilizer application maintained the lowest concentration of NH$_4$$^{+}$ -N in floodwater. The ammonia losses of urea+NBPT and urea+NBPT+DCD treatments were lower than those of urea and urea+DCD treatments during the 30 days after fertilizer application. It was found that N loss due to ammonia volatilization was minimized in the treatments of NBPT with urea and the slow-release fertilizer. The volatile loss of urea+DCD treatment was not significantly different from that of urea surface application. It was found that NBPT delayed urea hydrolysis and then decreased losses due to ammonia volatilization. DCD, a nitrification inhibitor, had no significant effect on ammonia loss under flooded conditions. The slow-release fertilizer application reduced ammonia volatilization loss most effectively. As N0$_3$$^{[-10]}$ -N concentrations in the soil water indicated that leaching losses of N were negligible, DCD was not effective in inhibiting nitrification in the flooded soil. The amount of N in plants was especially low in the slow-release fertilizer treatment during the early growth stage for 15 days after fertilization. The amount of N in the rice plants, however, was higher in the slow-release fertilizer treatment than in other treatments at harvest. Grain yields in the treatments of slow-release fertilizer, urea+NBPT+ DCD and urea+NBPT were significantly higher than those in the treatments of urea and urea+DCD. NBPT treatment with urea and the slow-release fertilizer application were effective in both reducing nitrogen losses and increasing grain yield by improving N use efficiency in direct-seeded flooded rice field.field.

• 한국작물학회지
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• 제45권4호
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• pp.232-236
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• 2000

To obtain a basic information on the development of effective control strategies for weedy rice in direct seeding rice cultivation, occurrence patterns of weedy rice as influenced by different cultural practices such as cultivation method, water management, seeding time, and tillage were investigated in field or pot experiments. High occurrence of weedy rice was observed in a continuous direct seeding paddy field as compared to machine transplanted one. Based on the percent of weedy rice panicle over three years trial, high ridged dry seeding was highest with 36.9%, followed by wet seeding with 30.9%, water seeding with 14.6% and machine transplanting rice with 0.8%, indicating 97.8% reduction in weedy rice occurrence by machine transplanting rice as compared with high ridged dry seeding. Germination of weedy rice was promoted to 83-94 % when rice panicle was flooded from September 30 to October 10 for 6 days and 74-88% for 9 days on October 20. Weedy rice occurrence was also substantially reduced by delayed seeding on June 10 and intensive tillage. The results suggest that machine transplanting rice be more effective cultural practice than flooding treatment, delayed seeding and intensive tillage when weedy rice problem occurs in direct seeded paddy field.