• Korean Journal of Soil Science and Fertilizer
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• v.22 no.2
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• pp.93-99
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• 1989

To investigate the effects of barley straw on microflora, acetylene reducing activity, enzyme activity and sugar in relation to nitrogen fixation in submerged soil. The obtained results were summarized as follow: Of the nitrogen fixing microorganisms, the number of Azotobactor tended to increase with the application of barley straw as the rice grew. The number of Clostridia were increased at the tillering stage of plant and decreased thereafter, and that of Blue-green algae tended to increase at the heading stage and to decrease thereafter. On the other hand, the number of Blue-green algae tended to increase by the application of barley straw. Acetylene reducing activity was decreased in the heading stage and increased in the harvesting stage. There was no difference of acetylene reducing activity between the application of barley straw and control. In submerged soil treated with barley straw, enzyme activity of ${\beta}$-glucosidase was increaded significantly but that of phosphatase was not entirely affected. Of the change of enzyme activity, the observation of ${\beta}$-glucosidase was increased at the heading stage and decreased thereafter, and the activity of phosphatase tended to decrease in the submerged soil when rice plants were not cultured and to increase in the submerged soil when rice plants were cultured. Protease tended to increase in the heading stage and increase in the tillering stage and heading stage with the application of barley straw. The change of sugar was decreased and hexose was increased in the tillering stage with the application of barley straw.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.2
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• pp.151-159
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• 2012

Direct seeding of rice is a time- and laborsaving method, compared to machine transplanting. However, the area planted to direct-seeded rice is decreasing because of instability of seedling establishment, lodging, occurrence of weedy rice, and deterioration of grain quality. A newly developed wet-hill-seeding of rice, a type of direct seeding method, has shown features of growth similar to machine transplanted rice. This study was carried out to compare tillering pattern, heading characteristics and grain filling traits between transplanting and wet-hill-seeding in rice. Tillering of wet-hill-seeded rice was more vigorous than that of transplanted rice showing maximum tiller number 30~100% higher than transplanted rice. Wet-hill seeded rice showed later heading and shorter heading duration than transplanted rice. To find out the relationship between heading characteristics and grain filling traits, every panicle was tagged for flowering date, and the panicles on each heading date were inspected for grain filling traits. Wet-hill seeded rice and transplanted rice exhibited no significant difference in culm length, panicle length, the percentage of grain filling and perfect brown rice on each heading date during total heading period. Therefore, we conclude that wet-hill-seeding method is not inferior to machine transplanting in terms of seedling establishment, growth, grain filling and head rice yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.1
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• pp.83-90
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• 2010

Crop characteristics of 179 sorghum (Sorghum bicolor L. Moench) resources collected in Korea were investigated in order to establish basic data for the improvement of crop breeding. Spike types of 179 sorghum resources were classified as 5 types of open-loose type, broom-tillering type, half broom-tillering type, extreme-compact type and compact type, of which broom-tillering type was the highest ratio of 38.0% (68 plant resources) of 179 germplasm. In the existence and nonexistence of spike awn in 179 sorghum resources, 28.5% (51 plant resources) showed existence of spike awn, whereas the rest of 71.5% (128 plant resources) had no spike awn. Seed type was classified as 5 types, of which circle-shape showed the highest ratio of 43.0% (77 plant resources) and the lowest was inclined-circle shape by 7.3% (13 plant resources). Seed color was classified as 4 colors of brown, white, whitish brown, and yellowish brown, of which yellowish brown was the highest ratio of 84.4% (151 plant resources) among them. Days from seeding to heading date showed the range from 67 to 88 days with the average of 77.4 days and the highest frequency proportion of it was the group from 76 to 80 days, which occupied 37.4% (67 plant resources) of 179 germplasm. 179 sorghum resources showed high variation in the range of culm length with the average of 253.8 cm and group from 92 cm to 360 cm of culm length showed the highest frequency proportion of 20.6% (37 plant resources). Spike length showed the range from 15 to 49 cm with the average of 28.8 cm and the highest frequency distribution of it was the group from 31 to 35 cm with the proportion of 26.3% (47 plant resources), whereas the lowest was below 15 cm with the proportion of 0.6%. Days from seeding to physiological maturity showed the range from 110 to 146 days with the average of 125.5 days and the highest frequency proportion (39.7%) of it was the group from 111 to 115 days, while there were also occupied with 2 plant resources below 110 days and 23 plant resources over 141 days among 179 germplasm. Number of grains per spike showed the range from 163 to 4,532 grains with the average of 2,068.6 grains and group from 1,601 to 2,000 grains per spike was the highest frequency distribution with the proportion of 25.7% (46 plant resources). 1000 grains weight showed the range from 10.6 to 38.1g with the average of 25.6g and group from 26.0 to 30.0g was the highest frequency distribution with the proportion of 44.1% (79 plant resources).

• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.4
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• pp.69-79
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• 1982

The objective of this study is to contribute to drainage planning in the most realistic and economical way by establishing the relationship between rice yield reduction and overhead flooding by muddy water of each growth stage of paddy, which is the most important factor in determining optimum drainage facilities. This study was based on the data mainly from the experimental reports of the Office of Rural Development of Korea, Reduction Rate Estimation for Summer Crops, published by Ministry of Agriculture and Forestry of Japan and other related research documenta- tion. The results of this study are summarized as follows 1. Damages by overhead flooding are highest in heading stage and have the tendency of decrease in the order of booting stage, panicle formation stage, tillering stage, and stage just after transplanting. Damages by overhead flooding of each growing stage are as follows: a) It is considered that overhead flooding just after transplanting gives a little influence on plant growth and yield because the paddy has sufficient growth period from floo ding to harvest time. b) Jt is analyzed that according to the equation y=11 12x 0.908 which is derived from this study, damages by overhead flooding during tillering stage for 1, 2, 3 successive days are 11.1 %, 20.9%, and 30.2% respectively. c) Damages by overhead flooding after panicle formation stage are very serious because recovering period is very short after damage and ineffective tillering is much. Acc- ording to the equation y=9. 58x+10. Ol derived from this study, damages by overhead flooding fal 1,2,3,5 successive days are 19.6%, 29.2%, 38.8%, 57.9% respectively. d) Booting stage is the very important period in which young panicle has grown up almost completely and the number of glumous flower is fixed since reduction division takes place in the microspore mother cell and enbryo mother cell. According to the equation y=39. 66x 0.558 derived from this study, damages by overhead floodingfor 0.5, 1, 3, 5 successive days are 26.9%, 39.7%, 72. 2% and 97.4%, respectively. Therefore, damages by overhead flooding is very serious during the hooting stage. e) When ear of paddy emerges, flowering begins on that day or the next day; when paddy flowers, fertilization will be completed 2-3 hours after flowering. Therefore overhead flooding during heading stage impedes flowering and increases sterilizing percentage. From this reason damages of heading stage are larger than that of booting stage. According to the equation y-41 94x 0.589 derived from this study, damages by overhead flooding for 0.5, 1, 3, 5, successive days are 27.9%, 63.1 %, 80.1%, and 100% 2. Considering that temperature of booting stage is higher than that of beading stage and plant height of booting stage is ten centimeters shorter than that of heading stage, booting stage should be taken as a critical period for drainage planning because possi- bility of damage occurrence in booting stage is larger than that of heading stage. There-fore, it is considered that booting stage should be taken as critical period of paddy growth for drainage planning. 3. Overhead flooding depth is different depending on the stage of growth. In case, booting stage is adopted as design stage of growth for drainage planning, it is conside red that the allowable flooding depth for new varieties and general varieties are 70cm and 80cm respectively. 4. Reduction Rate Estimation by Wind and Flood for Rice Planting of the present design criteria for drainage planning shows damage by overhead flooding for 1 to 2, 3 to 4, 5 to 7 consecutive days; damages by overhead flooding varies considerably over several hours and experimental condition of soil, variety of paddy, and climate differs with real situation. From these reasons, damage by flooding could not be estimated properly in the past. This study has derived the equation which shows damages by flooding of each growth stage on an hourly basis. Therefore, it has become possible to compute the exact damages in case duration of overhead flooding is known.

• Korean Journal of Weed Science
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• v.17 no.4
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• pp.368-374
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• 1997

Investigated ware the decomposition of mulch paper, weed occurrence, and rice growth and yield in transplanting rice culture with paper mulching in 1996 and 1997. The mulch paper were developed from domestic old corrugated container. In the experiment of 1996 where 25 percent of nitrogen fertilizer was applied as tillering fertilizer at 15 days after transplanting, it took about 28 to 40 days for the mulch paper to reach 50 percent decomposition according to types of mulch paper and fertilizer amount. The decomposition was faster in 18kg N/10a fertilization plot than in 12kg N/10a fertilization plot, and slower in the mulch paper treated with polyamidepolyamine epichlorohydrin resin(PPE) for the reinforcement of wet strength than in the mulch paper without PPE. In the experiment of 1997 where nitrogen fertilizer was not applied at tillering stage and instead 70 percent of nitrogen fertilizer was supplied as basal fertilizer, it took more than 42 days for the mulch paper(PPF treated) to reach 50 percent decomposition. Paper mulching was found to be very effective in controlling the paddy weeds at early stage of rice growth, but the efficacy, of weed control decreased especially in the mulch paper without PPE at later stage of rite growth due to the occurrence of Ludwigia prostrata in 1996. Few weeds occurred even in non-mulched plot without herbicide in 1997, rending difficulties in evaluating the efficacy of mulch paper in weed control, However, it could be deduced from the durability of mulch paper that paper mulching would have had sufficient efficacy of weed control. Rice yield was only 185kg/10a in the plot without mulching and weed control, but 657kg/10a and 771kg/10a in the paper(PPE treated) mulching plot with 12kgN/10a and 18kgN/10a, respectively, in 1996. The paper mulching plot showed rice yield similar to the weed control plot with herbicide in 1997. It would be concluded that paper mulching could ensure effective weed control and as high yield as the conventional rice cultivation with herbicidal weed control if the corresponding amount of basal nitrogen fertilizer is increased instead of omitting the nitrogen fertilizer at tillering stage.

• Korean Journal of Environmental Agriculture
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• v.22 no.3
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• pp.192-196
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• 2003

Objective of this study was to investigate the influences of harvest index and percolation water quality as irrigated the discharge waters from an industrial and a municipal wastewater treatment plants and seawater (1:5 seawater: tap water) as alternative water resources during tillering stage for drought stress. There were four different treatments such as the discharge water from an industrial (textile dyeing manufacture plant) wastewater treatment plant (DIWT), discharge water from the municipal wastewater treatment plant (DMWT), seawater (1:5) and groundwater as a control. For the initial chemical compositions of alternative waters, it appeared that higher concentrations of COD, $Mn^{2+}$, and $Ni^+$ in DIWT were observed than reused criteria of other country for irrigation, and concentrations of $EC_i$, Cl, and $SO_4$ in seawater were higher than that for irrigation. Harvest index was not significantly different between DIWT and DMWT with different irrigation periods in two soil types, but that of seawater (1:5) is decreased with irrigation periods in clay loam soil and not different between 10 days and 20 days of irrigation periods in sandy loam soil. For percolation water qualities, values of sodium adsorption ratio (SAR) are increased with prolonging the irrigation periods of seawater (1:5) and DIWT, but those of DMWT were almost constant through the cultivation periods regardless of the irrigation period in both soil types. EG of percolation waters is eventually increased with prolonging days after irrigation regardless of irrigation periods in both soil types. Therefore, it might be concluded that there was potentially safe to irrigate the discharge water from municipal wastewater treatment plant relative to harvest index, SAR and $EC_i$ values of the ground water through the rice cultivation period at tillering stage for drought period.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.3
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• pp.195-200
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• 1990

These experiments were conducted to determine the effect of high temperature and water managements on growth and yield of rice. Shoot dry weight and percent of fresh roots were decreased when rice plant was exposed to high temperature, and also high temperature treatment decreased yield components of rice through spikelet number at meiotic, filled grain ratio and percent of fertility at heading, and 1,000 grain weight at ripening stage. Nitragen content of the rice varities was decreased by high temperature treatment regardless different growth stage, although Si content increased. Grain yield of rice varieties significantly decreased due to high temperature when rice plants were treated at heading stage followed by ripening stage. meiotic, young panicle initiation, maximum tillering and tillering stage in order. Effect of the continual submerging on temperature increased by 1.1$^{\circ}C$ at daytime and by 3.7$^{\circ}C$ at nighttime, but flowing water irrigation which can maintain optimum temperature reduced plant height and increased dry weight and percent of fresh roots. Flowing water irrigation showed higher yield by 4-8% compared to continual submerging method through increment of yield components such as spikelet number, filled grain ratio and 1,000-grain weight.

• Korean Journal of Environmental Agriculture
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• v.1 no.2
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• pp.93-98
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• 1982

Effect of the application time on the persistence of IBP and isoprothiolane in rice plant was studied in the field and effects of the water depth and soil texture on their persistence were also tested as a pot experiment. When granules were applied to the rice paddy water, two fungicides were readily absorbed through the root system and rapidly translocated to the upper parts of the plant. The concentrations of two fungicides in rice plant reached to the maximum within 24 hr regardless of the application time. When applied at the maximum tillering stage, the persistence pattern of two fungicides in plant showed similar trends; that is, residue levels of two compounds declined rapidly upto 7 days after application but more slowly thereafter. When applied at the heading stage, the persistence pattern of IBP in plant was similar to the maximum tillering stage while isoprothilane was quite different; 3 ppm reached on 3rd days after application was maintained almost constant for further 25 days. There was no effect of the water depth on the persistence of two compounds in plant and IBP concentration in plant was also not affected by soil texture. However, isoprothiolane in plant was higher in sandy loam than in loam and clay loam. Isoprothiolane residues in plant were much higher than those of IBP.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.1
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• pp.32-40
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• 2003

To characterize diel pattern of methane transport via rice plant, methane emission was measured on specific days in rice growing stages; tillering, meiotic, heading and harvest stages, from a paddy under different water management and organic amendments. Methane emission was monitored every two hours a day from chambers with and without rice plants. Proportion of the rice plant-mediated methane emission at different stage increased till the maximum growth of LAI and dry weight, and decreased thereafter. The proportion of methane emission through rice plants on June 18-19 at tillering stage was 38.4, 36.5 and 64.3 percent for NPK, Rice straw compost, RSC, and rice straw on February, RS2, respectively. The proportion on July 30-31 at meiotic stage was 70.4, 74.3 and 74.4 percent for NPK, RSC and RS2, respectively. The proportion on August 20-21 at heading stage was 80.1, 84.5 and 74.8 percent for NPK, RSC and RS2, respectively. The proportion on September 28-29 at harvest stage was 69.9, 65.9 and 64.4 percent for NPK, RSC and RS2, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.3
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• pp.224-229
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• 1992

The objective of the study was to clarify the pattern of fertilizer absorption by tillering hybrid, IK$_1$/IRI. Nangano No.1 hybrid was included as non-tillering check hybrid. Hybrids were grown in pots and the plants were periodically analyzed for their chemical components like nitrogen, phosphorus, potassium, calcium and magnesium. The results obtained indicate that the amount of nitrogen, phosphorus and potassium absorbed by IK$_1$/IRI was slightly lower than that absorbed by Nangano No.1, except nitrogen in the maturity of IK$_1$ /IRI. However, no major differences were observed for the calcium and magnesium content between two hybrids. In most cases amount of nitrogen and calcium in the plant of two hybrids seemed to decrease as the plants mature, while amount of those chemicals in the ears increased. Nitrogen efficiency for IK$_1$ /IRI seemed a little lower than that for Nangano No.1.