• Korean Journal of Soil Science and Fertilizer
• /
• v.8 no.4
• /
• pp.177-181
• /
• 1975

The pot experiment was conducted primarily to clarify the relationship between lime application and they amount of potassium for the basal and top dressings on paddy rice. (Orizae sativa L. cultivar; variety Jinheung) The soils mixed with lime and without lime were separately filled in to 0.2827 a. open-bottom concretepots. The soil with lime was treated with slaked lime, at two weeks before transplanting to correct soil pH. around 7.0. The total amount of potassium 12 kilograms per 10a was applied by two or three split doses during transplanting, 19 days after transplanting and primodial stages. The results of experiment obtained are summarized as follows: 1. The application of potash in the rate of 4kg per 10a or less for basal dressing and the remaining amount of potash for top dressing at 19 days after transplanting and primodial stage or one top dressing, at primodial stage have increased the yield of paddy with increased number of panicles per hill, milliequivalent ratio of $K^-/Ca^{++}+Mg^{++}$ in leaves in the later stage of growth, number of ripened grains per panicle, and rate of grain maturity. 2. On the other hand, the greater the amount of potassium given for the basal dressing (over 4kilograms per 10a), the smaller number of tillers and panicles were resulted. And the tendency was considered chiefly due to high salt concentration at the early stage of rice growth.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.33 no.2
• /
• pp.195-200
• /
• 1988

This experiment was carried out to evaluate the flooding injury and yield compensating ability by uppernode tillers formed during the recovery periods. Rice plants grown in experimental field transplanted on 1st, June were completely flooded for 3 days by the artificial flooding device in each different growth stage such as middle tillering stage (20 days after transplanting), young panicle formation stage, meiotic stage and heading stage. And the farmer's rice fields which had various transplanting dates were completely flooded for 3 days by typhoon 'Thelma' from 16th to 18th, July, 1987. Percent of dead leaves and yield reduction of rice in experimental field flooded at the different growth stages were resulted that the earlier growth stages were the lower damage because of the low temperature in the earlier growth stage, but it showed opposite tendency in farmer's rice field flooded in high temperature season by typhoon 'Thelma'. Rice yield compensating ability attained to 66% of check plot yield was greatly depend on uppernode panicles induced after damage of original young panicles. Uppernode panicle produced 236 kg per 10a in polished rice by securing 690$^{\circ}C$ of accumulated mean temperature and 210 hours of sunshine during the ripening periods when headed up to 15th of September.

• Korean Journal of Agricultural Science
• /
• v.42 no.2
• /
• pp.111-116
• /
• 2015

Combined applications of rice bran with pine leaves were tested to examine the inhibitory effects to paddy weeds and increased yield of rice for developing techniques of environment-friendly weed management in paddy rice fields. Weed control efficacy at 60 days after treatment was improved to 88.8% by combined application of rice bran with pine leaves, while weed control efficacy by single application of rice bran showed 67.5%. The other weed control efficacy combined with chestnut leaves and barley straws were 76.3% and 69.9% respectively. Combined application of rice bran with pine leaves was more effective to broadleaf weeds such as Monochoria vaginalis. Weed control efficacy by combined application with pine leaves was 100% until 70 days after rice transplanting and maintained weed control effect up to 90 days after transplanting. Rice yield by combined application of rice bran with pine leaves was 526 kg/10 a, which was higher yield than by combined application with barley straws, single application of rice bran, natural snail application and hand weeding.

• Korean Journal of Organic Agriculture
• /
• v.19 no.spc
• /
• pp.119-122
• /
• 2011

Among the developed bio-degradable polymer films as compared with transparent film(White), black polymer film was significantly more effective for controlling weeds in red pepper. Also, we found that white and black polymer mulching had 81.8% and 97.9% of managing weed controlling effects in rice, respectively. Compared to non-mulched rice paddy with water supply, the non-mulched rice paddy without any water supply has stopped its growth at 41 days after transplanting, while polymer-mulched rice paddy without water supply had about 60% of normally growing rice plants. This shows the polymer treatment has a remarkable effect on water and power saving, solution of herbicidal resistance, avoidance of herbicidal influence to eco-system etc. When the naturally decomposing polymer was used, a temperature was elevated as high as $4.7^{\circ}C$ on maximum and $2.6^{\circ}C$ on average. Also the naturally decomposing polymer accelerated rooting by 7 days and lowered a stress level from transplanting. The weed control effect mulched by polymer was remarkable as 98.7%. The polymer now, after 294 days treated on the rice paddy, has been completely decomposed.

• Korean Journal of Environmental Agriculture
• /
• v.15 no.2
• /
• pp.198-206
• /
• 1996

Leaching of $^{54}Mn$, $^{60}Co$, $^{85}Sr$ and $^{137}Cs$ in paddy soil was studied using lysimeter cultures in a greenhouse. The radionuclides were applied to the water surfaces shortly before transplanting and five different times between transplanting and harvest. Fertilizer KCl and slaked lime were added simultaneously in the rate of 83kg and 200kg, respectively, per l0a following the first application after transplanting. Percolating water was sampled until two days before harvest. Concentrations of the radionuclides in percolating water decreased in the order of $^{85}Sr$ > $^{54}Mn$ > $^{60}Co$ > $^{137}Cs$ on the whole. Time taken to reach the maximum was the shortest for $^{137}Cs$(< one week) and the longest for $^{54}Mn$ and $^{85}Sr$. Six days' water dropping started 47 days after transplanting reduced the concentrations of $^{54}Mn$, $^{60}Co$, $^{85}Sr$ and $^{137}Cs$ by factors of 30-180, 3-75, 2-4 and 3-6, respectively, depending on the application time. After the significant decrease, $^{54}Mn$ concentration tended to gradually increase but $^{137}Cs$ did to the contrary Percent leaching varied 0.09-6.2% for $^{54}Mn$, 0.009-0.9% for $^{60}Co$, 1.4-14.4% for $^{85}Sr$ and 0.002-0.06% for $^{137}Cs$, with the application time. The highest leaching came from the application at 40 days after transplanting for all the radionuclides. The addition of KCl and lime increased percent leaching of the radionuclides by factors of 9, 85, 4 and 9, respectively.

• Journal of Bio-Environment Control
• /
• v.28 no.3
• /
• pp.185-196
• /
• 2019

Abstract. This research was conducted to figure out the optimal size of the plug cell and seedling raising period in 'Nongwoo' and 'Nonghyeop' cultivars. In the first experiment on effect of plug cell size on growth of squash, seedlings were transplanted into hydroponic cultivation beds at different growing stages: Those in 32-cell trays with 3-4 true leaves at 25 days after sowing, those in 50-cell trays with 2 true leaves at 15 days after sowing, those in 105-cell trays just before a true leaf development, and those in 162-cell trays with only cotyledons at 8 days after sowing. In the second experiment on effect of seedling raising period on growth of squash, it was conducted to have different sowing dates. But the same transplanting date, based on the results of Experiment 1, and compared the differences in growth and fruit productivity as affected by plug cell size in the same way with experiment 1 including the cultivars and environmental conditions. After setting the transplanting date in advance, the number of days for sowing were calculated back for each treatment. In the first experiment, plant height was the greatest in 105-cell trays followed by 162, 50 and 32-cell trays in both cultivars. The best fruit quality was found in different treatments depending on the cultivars, although it was the lowest in 32-cell trays in both cultivars. The fruit quality was not significantly different among those from cell sizes. Therefore, when raising seedlings in 105-cell trays, the period of raising seedlings can be shortened as compared with the conventional 32-cell trays, and this change could reduce the workforce required for growing and transplanting seedlings. In the second experiment, after transplanting, shoot height and leaf width in the first measurement in both cultivars were greater in the 32-cell treatment. However, the last measurement after four weeks showed no significant difference in plant height, but significantly greatest leaf width in the smallest cell treatment, even as compared with that in 32-cell treatment. In case of 'Nongwoo', length and weight of the first harvested fruit showed the highest values in the treatment of 105-cell trays. In case of 'Nonghyeop' the 162-cell treatment along with the 105-cell treatment showed greatest length and weight of the first fruits. From these results, zucchini plug seedlings can be raised in plug trays with reduced cell sizes than the conventional 32-cell trays with improved fruit productivity.

• Journal of the Korean Society of Tobacco Science
• /
• v.3 no.2
• /
• pp.103-108
• /
• 1981

This experiment was carried out to investigate effects of soil moisture content on the growth of tobacco plant at early stage after transplanting. Soil moisture was controlled to be 30%, 45%, 60%, 75% and 90% of the maximum water holding capacity (38.7%), and treated for 10, 20 and 30 days. Budding flowering and topping were delayed in the 30% and 45% treatment where soil moisture was deficient. Plant height, number of leaves, and length and width of the largest leaf were the best in the 75% treatment for 10 days, and development of the root and top was the best also in the same treatment. As the duration of low soil moisture treatment prolonged, intercellular space , became small. Nitrogen and potassium of the cured leaf showed the highest value in 30% and 45% treatments. Nicotine content of the cured leaf was high in the 90% treatment, and reducing sugar content of that was high in the 75% treatment for 10 days.

• Journal of the Korean Society of Tobacco Science
• /
• v.11 no.1
• /
• pp.19-25
• /
• 1989

Effect of removal time of mulched polyethylene film on the chlorine content of toP soil and on the chlorine absorption by burley tobacco Plants was investigated under the field condition in 1986 and 1987. Treatment consisted of 4 removal times (from 30 to 75 days after transplanting with IS days interval) and control (no removal). The chlorine content of top Boll at 15 days after removal of mulched polyethylene film(MPF) lowered temporarily, and the decrement of chlorine content of top soil was closely related to the sum of rainfalls after removal of MPF. The chlorine was accumulated much in upper leaves when the MPF being removed early, while the chlorine was accumulated much in lower loaves when the MPF being removed late, relatively. However, the removal of MPF had no effect on the chlorine content of whole leaf. The yield decreased with removal of MPF during growing period.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.14
• /
• pp.159-164
• /
• 1973

This study was carried out in the central part of Korea for three years from 1970 to 1972. Its aim was to investigate the variations of growth and yield of rice varieties of different cultivating methods (transplanting culture, direct sowing culture on irrigated paddy field, and direct sowing culture on non-irrigated paddy field. The results could be summarized as follows; 1. The number of days from sowing to heading by direct sowing culture on irrigated paddy field was remarkably shorter than transplanting culture. Direct sowing culture on non-irrigated paddy field was longer than transplanting culture. 2. The number of panicles showed direct sowing culture on irrigated paddy field was first, direct sowing culture on non-irrigated paddy field was second, and third transplanting culture. But the number of spikelets per panicle was first on the transplanting culture, second on the direct sowing culture on non-irrigated paddy field and third on the direct sowing culture on irrigated paddy field. 3. The weight of the brown rice showed that direct sowing culture on irrigated paddy field produced the highest yield among the cultivating method in all varieties. The transplanting culture increased more than the direct sowing culture on non-irrigated paddy field. The highly productive varieties were Sadominory, Akibale, Suwon 213-1 when the direct sowing culture on irrigated paddy field was used. 4. The correlation between the brown rice yield and the yield components were as follows; in each cultivating method, it showed highly significant positive correlation between the brown rice yield and the 1, 000 grain weight of hulled rice, and between the brown rice yield and the number of the spiklets per panicle in the transplanting culture, in the direct sowing culture On irrigated paddy field between the brown rice yield and the number of spikelets per panicle and between the brown rice yield and the number of panicles, in direct sowing culture on non-irrigated paddy field between the brown rice yield and number of panicles. 5. It showed highly significant negative correlation between the brown rice yield and the number of days from sowing to heading in the direct sowing culture on irrigated and non-irrigated paddy field, but it was showed very low negative correlation in the transplant culture.

• Korean Journal of Weed Science
• /
• v.7 no.3
• /
• pp.280-288
• /
• 1987

The experiment was carried out to clarify the root competition between rice and paddy weed. Sagittaria pygmaea, under field condition. Rice variety Joongwonbyeo(Tongil type) and Sangpoongbyeo(Japonica type) were transplanted and Sagittaria tuber was planted artificially at planting density of untreated control, 4, 8 and 16 tubers/$m^2$, respectively. The number of roots, root fresh weight and root activity of rice and Sagittaria were measured at 30, 45, 60 and 75 days after transplanting. The results obtained were as follows. The root growth of Joongwonbyeo was decreased greatly according to the increase of Sagittaria tuber density compared with Sangpoongbyeo. On the other hand, the root growth of Sagittaria competed with Joongwonbyeo was depressed at 45 days after transplanting, and the one competed with Sangpoongbyeo was depressed at 60 days after transplanting. It was concluded that the competition ability of Sangpoongbyeo against Sagittaria was greater than Joongwonbyeo mainly due to the tall height and large tillers. And also the root growth of Sagittaria competed with Joongwonbyeo was more depressed than that of Sangpoongbyeo.