• Korean Journal of Weed Science
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• v.7 no.1
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• pp.98-106
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• 1987

The effect of carbofuran (2, 3-Dihydro-2,2-dimethyl-benzofuran-7-ylmethyl carbamate) on rice growth was evaluated as a direct growth stimulant of rice. For this, several laboratory and field trials conducted from 1981 to 1986 at the Yeongnam Crop Experiment Station. Carbofuran solution affected the germination of rice seed. The growth of seminal roots was adversely affected by the increase of carbofuran concentrations while the length of single root became longer with the concentration increment up to 50 ppm. Carbofuran application (0.18g ai/$m^2$) at the rice nurserybed significantly enhanced the rice growth and recovered from the Low temperature damage. The enhancement effect was more pronounced at the plot that applied carbofuran before rice seeding as soil incorporation than top-dressing. The effect of growth enhancement further extended to transplanted lowland rice. This effect was greater at double cropping area (late of June transplanting) compared to single cropping area (May transplanting). Among important agronomic traits, the increment of panicle number was the most important direct effect for increasing rice grain yield by carbofuran application. Carbofuran application also exhibited the reducing effect against low temperature damage at reductive division stage and at rice heading stage and against submergence damage at booting stage through enhancement of fertile grain ratio, ripening ratio or photosynthetic activity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.805-809
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• 1997

The influence of cool temperature occurred during the booting stage in 1993 on quality of rice grain was compared with that in favorable weather of 1994. The mean and minimum air temperatures during the reproductive growth stage at the paddy field of Jinbu Substation, National Crop Experiment Station were 2.2~7.4$^{\circ}C$ and 2.0~8.9$^{\circ}C$ lower respectively in 1993 compared to those of 1994. Grain fertility and brown rice yield were 11.8％ and 0.4t /ha, and 84.3％ and 5.5t /ha in 1993 and 1994, respectively. There was no difference in amylose content between two years. However, protein content of brown rice in 1994 were 1.6％ lower than that of 1993. There was no difference in alkali digestion value of milled rice between two years. Gel consistency of rice flour was 45mm in 1993 and 59mm in 1994. Amylogram characteristics of rice flour produced in 1993 showed lower peak hot, cool, and breakdown viscosities, and higher consistency and setback viscosities. The palatability of cooked rice by sensory panel test was considerably better in 1994 rice than in the rice of cool year.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.4
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• pp.309-314
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• 1990

A pot experiment was carried out to find the effects of chemicals and its application time on the sterility and other agronomic characters of rice. Two rice cultivars, Samgangbyeo, a Tongil type, and Chuchungbyeo, a japonica type rice were treated with maleic hydrazide (6000ppm), ethephon (6000ppm) and GA3 (10ppm) at five different growth stages. The application times of chemicals were comprised of two different stages of stem elongation and booting and panicle emerging stage. Grain sterility and panicle length were measured for panicles per pot. Culm length was measured for pot basis. MH induced complete grain sterility in rice, but caused severe plant damage (phytotoxicity) ; restricted spike emergence and drying out of plant leaves, sheath and panicles. Ethephon induced 50-60% grain sterility in rice with the least in plant damage. GA3 was not effective in inducing grain sterility in rice, but it increased culm length. The earlier application of chemicals, the higher sterility was induced. Both MH and ethephon reduced culm length and grain yield. Also observed was the varietal response in the occurrence of to chemicals Samgangbyeo showed the higher response to chemicals than Chuchungbyeo.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.3
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• pp.311-317
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• 1986

To obtain the basic informations on the variation of rice grain shattering under different environmental conditions, several experiments were carried out from 1982 to 1985. The degree of grain shattering was significantly differed depending upon the harvesting time after heading in some rice varieties. It appeared that the ratio of grain shattering was greatly affected by the drying period after harvesting; the ratio of grain shattering of sun-dried seeds for 6 days after harvesting was higher than those of the just harvested seeds. Grain shattering was increased at high level of nitrogen and decreased with delay in transplanting date. Yearly differences in grain shattering was more clearly recognized in easy-shattering varieties in comparison with those of non-shattering varieties. Rice grain shattering also increased by the low temperature treatment (l7/15$^{\circ}C$, day/night) at booting stage, 5 to 11 days before heading. A rice variety, Milyang 23, belong to easy shattering group was more pronounced at the low temperature condition with shading. In general, it was always possible to classify the cultivar differences between easy-shattering and non-shattering groups regardless of any environmental condition. Thus results suggested that rice grain shattering will be largely governed by genetic factors.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.5
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• pp.383-390
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• 1993

This experiment was carried out in the green house at Tokyo University of Agriculture in 1992 to investigate the relationship between lodging resistances and specific morphological characters and to examine the effects of nitrogen top-dressing and growth retardant on changes of the endogenous ethylene content in rice plant. Inabenfide did not affect significantly yield, yield component, chlorophyll content, and $CO_2 assimilation but, decreasing plant height when growth regulators were applied at booting stage, decreasing internode elongation, and increasing culm thickness and diameter of the third and fourth internode. While, nitrogen top-dressing usually showed to effect increasing vegetative growth such as plant height, tiller number, and morphological characteristics but, were not significantly affected the chlorophyll content and $CO_2 assimilation. Ethylene evolution was dramatically changed with nitrogen top-dressing and growth retardant. Application of Inabenfide at 15 days before heading inhibited ethylene evolution in the all nitrogen levels. Higher nitrogen top-dressing showed higher ethylene evolution than that of low nitrogen level. High positive correlation was detected between nitrogen application and ethylene evolution.

• Journal of Biosystems Engineering
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• v.16 no.1
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• pp.37-48
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• 1991

Rice plants are subjected to various forces such as natural force of wind and mechanical force of cultivating machines. Rheological behavior of the rice stem can be expressed in terms of three variables : stress, relaxation and time. The objectives of this study are to examine stress relaxation, creep and recovery characteristics on the rice stem in case of axial and radial loading. Stress relaxation with time was studied on three levels of loading rate and on four levels of applied stress. The results were summarized as follows : 1. The hysterisis losses of the rice stem distinctly observed at the radial compression in comparison with axial compression. The hysterisis loss implied that the stem to absorbed energy without being deformed beyond the yield point. 2. Ageneralized Maxwell model consisting of three elements gave a good description of the relaxation behavior of the rice stem. Rate of loading was more significant on the observed relaxation behavior within the short relaxation time, but there were little influences of rate of loading on the relaxation time. 3. The stress relaxation intensity and the residual stress increased in magnitude as the applied stress increased, but the relaxation time was little affected by the applied stress. 4. The coefficients of the stress relaxation model showed much differences in the radial compression and the axial compression, especially the higher relaxation stress of the third element was observed in the radial compression. 5. The behaviors of rice stem in creep and recovery test also might be represented by a four element Burger's model. But the coefficients of the creep model were different from those of the recovery model. 6. The steady-state phenomena of creep appeared at the stress larger than 20 MPa in Samkang and 1.8 MPa in Whajin. 7. The elastic modulus of the stem showed the range from 40 to 60 MPa. It could be considered, as a result, the rice stems had viscoelastic properties.

• Magazine of the Korean Society of Agricultural Engineers
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• v.23 no.2
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• pp.35-44
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• 1981

This experiment was conducted to find out the consumptive use of irrigated water for calculation of duty water in paddy rice. Tall statured Japonica rice varieties, Nongbaek (early), Jinheung (medium) and Akibare (late), and short statured Tongil typed varieties, Josaeng Tongil(early), Suweon 264 (medium) and Suweon 258(late) were planted on the experimental farm of Kon-Kuk University in 1979. The results obtained in this study were as follows: 1. During the experimental period, the daily mean temperature was almost similar, the relative humidity was higher as much as 2.8%, the amount of rain fall was 100mm less and the pan evaporation was 70mm less compared with those of 30 years average, respectively. 2. The paddy soil was silty loam, which was suitable for the rice cultivation. 3. Varietal differences were find out for plant height, culm length, number of tillers, number of panicles, heading date, matured grain ratio, 1000-grain weight and rough rice yield. This difference might he the cause of varietal difference of the consumptive use of irrigated water during the rice growing period. 4. The evapotranspiration was gradually increased after transplanting and showed the peak from booting to heading stage of rice varieties. The average evapotranspiration through the whole growing period was 5.67-5. 80mm/day for tall statured Japonica varieties, and 5.99-6. 39mm/day for short statured Tongil typed varieties. 5. The ratio of evapotranspiration to pan-evaporation through the whole growing period was 1.49-1.50 for Japonica varieties, and 1.60-1.66 for Tongil typed varies. 6. Average amount of percolation in paddy field was 3. 62mm/day through the whole growing period of rice plant. 7. K-value in Blaney & Criddle formula was 0.94-0.98 for Japonica varieties and 1.02-1.08 for Tongil typed varieties, and coefficient consumptive water use (Kc-value) was 0.95-1.02 for Japonica varieties and 1.04-1.12 for Tongil typed varieties in this study. The modified coefficient for consumptive water use, which was calculated from data collected through the country including this study, was as follows;

• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.2
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• pp.157-162
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• 1998

This experiment was carried out to investigate the effects of harvesting date and additives on the quality of fall sown oat(Avena sativa L.) silage at the department of animal resources science, college of life resources science, Woosuk University, Wanju &om August, 1997 to March, 1998. The experiment was arranged in a split plot design with three replications. The main plots consisted of the harvesting date such as 15 Oct., 23 Oct. and 2 Nov. and different additives as subplots(control, wheat bran, formic acid, lactic acid bacteria, and wilting). The results otained are summarized as follow : The fiesh and dry matter yield of oat were increased by harvesting date delayed, then fiesh and dry matter yield at 2 Nov. were highest as 36,733 and 7,29Okg/ha, respectively. The dry matter content of oat silage was increased significantly by harvesting date delayed(P< 0.05), and DM content of wheat bran and wilting treatment was high at every harvest date. The DM loss was lower in LAB, formic acid and wheat bran treatment, but on significant difference was found among harvesting date(P< 0.05). Average pH of silage harvested at 23 Oct. was lowest as 4.06, and the quality(CP, NDF, ADF, and IVMDM) of oat silage was decreased by harvesting date delayed. The content of acetic acid was no difference among harvesting date, but butyric acid was decreased and lactic acid was increased at 23 Oct. harvest. The result of this study indicate that oat harvested at booting-heading stage of maturity with wilting wheat bran, and LAB could be recommended as producing high quality of oat silage.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.1
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• pp.61-70
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• 2004

Silage additives are needed to increase the quality of whole crop rice silage which seldom produce without the additives due to both high pH and butyric acid concentrations. Little information, however, is available about the silage fermentation of whole crop rice added with silage additives in Korea. This study was conducted to determine the optimum levels of silage additives by evaluating the effects of latic acid bacteria (LAB) and formic acid concentrations on the silage quality of whole crop rice harvested at different mature stages. Field study was established early in May until October 7th on a rice field at Yupori, Sinbuk-yeup, Chunchon, Kangwon-Do. "Ilpum" mutant rice was harvested at six different mature stages; booting stage (17 Aug.), milk-ripe stage (27 Aug.), dough stage (7 Sep.), yellow ripe stage (17 Sep.), dead ripe stage (27 Sep.) and full ripe stage (7 Oct.). Each sample was ensiled in three different ways; with 1) LAB (0.05, 0.1 and 0.2% of sample wt), 2) formic acids (0.2, 0.3 and 0.4% of sample wt.) and 3) no additive. The additive levels did not affect dry matter content, crude protein, fiber and total digestable neutriant concentrations at all stages. Addition of additives significantly decreased the silage pH and butyric acid concentrations which tended to be more decreased with higher levels of additives. Latic acid concentrations were higher with the use of additives, especially with LAB. The lower concentrations of ammonia-N were observed in additive treatments at all stages, but the concentrations of ammonia-N did not differ according to the additve levels after yellow ripe stage (0.69, 0.60 and 0.71% of DM in 0.05, 01 and 0.2% of LAB, respectively; 0.64 0.59 and 0.75% of DM in 0.2, 0.3 and 0.4% of formic acid, respectively). These results indicate that the optimum addition levels of LAB and formic acid are 0.5∼0.1% and 0.2∼0.3%, respectively, on which the high quality of rice whole crop silage was produced. produced.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.2
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• pp.80-92
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• 1977

This experiment investigated the effect of various moisture levels on the top and root growth of barley and its yield. Resistant varieties to excess moisture injury shortened plant height, but tillered more, having creeping plant type compared with ordinary one, and greater portion of root of this varieties occured at the deeper soil depths with longer root length. However, susceptible one to excess moisture injury showed an inversed trend when compared with the untreated one. Oversaturated treatment compared with the untreated increased a little bit soil temperature and Eh of soil. Increased root activity and increased yield were obtained with resistant varieties compared with the untreated. Lower root activity and less yield than those of the untreated were observed in both extreme treatments. Yield reduction in both the extreme treatments was mainly due to reduction of tiller number, grain number and 1, 000-grain weight. Highest yield reduction was marked at the stage of internode elongation in the oversaturated and at the booting stage in the overdried treatment.