• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.1
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• pp.107-114
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• 1983

The study was carried out to find out the reasonable fertilization method for rice in the area of Irish potato cultivated paddy where has various nutritional disorders and pest problems. The treatment consisted of three different application methods of potato sterns and leaves with 4 levels of nitrogen application in each method. The application of potato sterns and leaves caused more release of $NH_4$ -N in the soils but the growth of rice were slightly hindered by the strongly reduced soil conditions when the nitrogen had been applied more than 10kg/10a. The application of half-dried or semi-decomposed stems and leaves of potatoes were caused to increase ripening ratio and 1,000 grain weight of rice with a relatively high $SiO_2$/N ratio in the rice plant, so the yield of rice increased 3-5% than the plot without potato sterns and leaves. The potash and silicate fertilizer would seem to be effective in the area of Irish potato cultivating paddy field since the contents of extractable potassium and soluble silicate in the soils is lacked. The suitable amount of nitrogen on rice cropping seems to be about 7kg/10a.

• The Korean Journal of Ecology
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• v.17 no.1
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• pp.59-67
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• 1994

Differences in physicochemical characteristics of sediment and changes in density, height and dry matter of shoots along different water depths were investigated in the stands of Zizania latifolza populations of the littoral zone of Lake Paltangho, Korea. Any significant differences in sediment chemistry were not found along water depth, although sand content decreased slightly with increasing depth. Shoot density of Zizania latqolia decreased with increasing water depth. In shallower water, many of the short shoots died in the early growth stages. The morphology of shoots was taller and heavier in deeper water. The distributions of shoot heights became negatively skewed and leptokurtic as plants grew, and these changes occurred in the earlier growth stages in deeper water. The standing crop of shoots increased with increasing water depth. These results suggest that Zizania lattfolia has a growth strategy for adjustment to deep water through decreasing shoot density and increasing height.

• Korean Journal of Plant Resources
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• v.14 no.1
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• pp.43-47
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• 2001

For the purpose of sweet potato varietal improvement, yulmi, shinyulmi, gunmi, hongmi and seonmi, whose source and sink are different one another, were cultivated at different amount of fertilizers, and then defoliation at initial stage of tuberous root weight increase on the relation of source and sink was observed as follows. The response of stem, leaf and tuberous root weight by amount of fertilizer and defoliation rate of sweet potato varieties was different. Stem and leaf weight increased along with heavy dressing by the following order; shinyulmi> seonmi> hongmi> gunmi> yulmi. Tuberous root number was the most at $N-P_2O_5-K_2O=60-70-190kg/ha$ amount of fertilizer, showing seonmi the most number. The number of stem, leaf and tuberous root increased along with the lowered rate of defoliation. In case of $N-P_2O_5-K_2O=20-30-90kg/ha$ amount of fertilizer, tuberous root weight increased by increase of stem and leaf weight up to 50% defoliation and the difference of stem, leaf and tuberous root number was low as defoliation rate increases. The total dry weight matter was the most at heavy dressing amount of fertilizer.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.147-150
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• 2002

To investigate the effects of Harvesting time and additives on the quality of peanut silage, the silage was mixed in combination with peanut leaf and stem, rice and barley straw, inoculant etc. Harvesting time at peanut growth stage was the best at 90 days after flowering with 30 branches,81 g of 100-seed weight, and 77% of shelling rate with low diseases in leaf and stem. By delay of harvest, diseases and lodging were increased. The yield of forage was the highest at 90 days after flowering as 52 t/ha, and seed yield was at 110 days as 3.72 t/ha. The yields between forage yield and seed yield ($r^2$=0.62$^{**}$) were correlated positively. The value of silage as a forage came over 90 days after flowering in combination with peanut leaf+stem+vice straw+inoculant treatment. The treatment was increased dry matter (DM) yield and neutral detergent fiber (NDF), the coarse protein (CP), and total digestible nutrient (TDN) content of silage in comparing with control (peanut leaf+stem). The pH at the organic matter contents of silage in combination of peanut leaf+stem+rice straw+lactic acid treatment was 5.04 to 5.10, the content of butyric and lactic acid were 3.12 to 4.64%, 2.07 to 7.34%, respectively.y.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.143-146
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• 2002

This study was undertaken to learn what ratio of clipping top was the most optimum for minimizing of the decrease of root yield of over 50g in sweetpotato at early cultivation. The test variety was "Shinyulmi" which was transplanted for early cultivation on April 18. The ratios of cripping top were 5, 10, 15, 20, and 25 percents. The date of clipping top was June 20 when the shoots were transplanted for double cropping. The total length of vine, the number of branches per plant, the number of tuberous roots over 50g and average root weight over 50g were not affected by clipping top. The ratio of root yield over 50g was lower over 20 percents of clipping top. The fresh weights per plant of top and bottom were similar as compared control with 15 percents of clipping top. In conclusion, the optimum ratio of clipping top was 15 percents for maximizing of the production of the shoots in sweetpotato for double cropping. cropping.

• Korean Journal of Plant Resources
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• v.12 no.4
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• pp.269-275
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• 1999

For the purpose of sweet potato varietal improvement, yulmi, shinyulmi, gunmi, hongmi, and seonmi, whose source and sink are different, were cultivated at different planting densities, and then defoliation at initial stage of tuberous root weight increase on the relation of source and sink was observed as follows. The response of stem and leaf and tuberous root weight by planting density and defoliation rate of sweet potato varieties was different. Stem and leaf weight per m$^2$ increased along with dense planting by the following order; shinyulmi> seonmi> hongmi> gunmi> yulmi. Tuberous root number per m$^2$ was the most at 75$\times$20cm planting density, showing seonmi the most number. The number of stem and leaf and tuberous root increased along with the lowered rate of defoliation. In case of 75$\times$10cm and 75$\times$20cm planting density, tuberous root weight increased by increase of stem and leaf weight up to 50% defoliation and the difference of stem and leaf and tuberous root number was low as defoliation rate increases. The tuberous root and total dry weight matter was the most at 75$\times$20cm planting density. The increase and decrease of source synchronized with those of sink at 75$\times$10cm and 75$\times$20cm, however the relationship occurred less at 75$\times$30cm.

• Korean Journal of Weed Science
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• v.18 no.4
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• pp.304-313
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• 1998

Foliar retention of pyribenzoxim (1% EC) was measured using the fluorescent dye rhodamine B, and related to efficacy and phytotoxicity to barnyardgarss (Echinochloa crusgalli) and rice (Oryza sativa cv. Chucheong), respectively. Effects of nozzle types (8002E flat-fan and disk-type), addition of adjuvant, variation of herbicide concentration or spray volume were compared. In barnyardgrass, foliar retention of pyribenzoxim at a recommended condition (application rate : 30g ai/ha, spray volume : 1000 L/ha) was 2.3 to 2.7 or 1.4 to $1.5{\mu}g$ ai/g fresh foliage when sprayed using the disk-type nozzle with or without adjuvant, respectively, and 0.6 to 0.7 or 0.3 to $0.5{\mu}g$ ai/g fresh foliage when sprayed using the flat-fan nozzle with or without adjuvant, respectively. The slope of increase in foliar retention was 1.0 to 1.8 when application rates increased from 10 to 60g ai/ha at 1000 L/ha, while that was 1.6 to 2.4 when spray volume increased from 330 to 2000 L/ha at $30{\mu}g$ ai/L concentration. Foliar retention of pyribenzoxim had a close relationship with herbicidal activity; regardless of spray conditions, retention to provide 90% control was about $0.8{\mu}g$ ai/g fresh foliage, and below this retention amount, efficacy decreased almost linearly. In rice, foliar retention at the recommended condition was 1.9 to 2.3 or 1.2 to $1.3{\mu}g$ ai/g fresh foliage when sprayed using the disk-type nozzle with or without adjuvant, respectively, and 0.6 to 0.9 or $0.3{\mu}g$ ai/g fresh foliage when sprayed using the flat-fan nozzle with or without adjuvant, respectively. The slope of increase in foliar retention was 1.0 to 2.8 when application rates increased from 30 to 120g ai/ha at 1000 L/ha, while that was 1.3 to 4.4 when spray volume increased from 1000 to 4000 L/ha at $30{\mu}g$ ai/L concentration. Despite the great difference in retention, rice phytotoxicity was not observed in any of these spray conditions, suggesting retention differences within 4-fold increase of application rate or spray volume do not affect rice safety. When pyribenzoxim 1EC was sprayed in tank-mix with several other commercial pesticide formulations, its retention to rice foliage tended to increase by 30 to 50%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.6
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• pp.486-491
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• 2002

Spikelet number and its components of rice plant are closely associated with nitrogen accumulation and biomass production during panicle formation stage. To elucidate this relationship and also compare the differences of the sink formation efficiency among cultivars, spikelet number, its components, nitrogen content, nonstructural carbohydrate content, and plant dry matter were investigated under 5 nitrogen levels with two split application methods and shading treatments by using three rice varieties. The nitrogen amount in shoot at panicle initiation stage and at 15 days after panicle initiation showed significant positive correlation with primary rachis branches per square meter, and that at 15 days after panicle initiation and at heading stage with secondary rachis branches per square meter, Primary and secondary rachis branches per square meter showed positive significant correlation with the shoot dry weight at panicle initiation stage and at 15 days after panicle initiation stage, respectively, The amount of degenerated secondary rachis branches and spikelets per square meter showed significant negative correlation with the dry weight and nonstructural carbohydrate increase of stem during 15days after panicle initiation, and the contents of nonstructural carbohydrate at 15 days after panicle initiation. Spikelets per unit area showed significant positive correlation with nitrogen amount in shoot and shoot dry weight at heading stage. The sink formation efficiency expressed as the spikelet number produced by the unit amount of nitrogen in shoot at heading stage was higher in Nampoongbyeo than Choocheongbyeo and Hwaseongbyeo. Sink formation efficiency was negatively correlated with the dry weight increase of shoot and stem during reproductive stage. but not significantly with that of leaf in all varieties. Sink formation efficiency was not significantly correlated with nonstructural carbohydrate, but was significantly negatively correlated with structural carbohydrate increase during reproductive stage.

• Korean Journal of Plant Resources
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• v.26 no.5
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• pp.539-547
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• 2013

This study investigates the change of chemical components, antioxidant and antimutagenic activity in Glycyrrhiza uralensis Fischer stems and leaves (GU) by the various processing methods, as follows: fresh (GU-1), dried under the shade (GU-2), blanched (GU-3), roasted 3 times (GU-4), roasted 4 times (GU-5). The components have been identified and quantified through the use of gas chromatograph-mass spectrometry (GC-MS). At results, cis-1,3-dimethyl-2-methylenecyclohexaneat at 19.7 min and n-hexadecanoic acid at 21.5 min were detected in five kinds of extract. 3-O-Methyl-D-fructose at 17.8 min was observed in four extracts except in GU-1 and aminopyrazine at 19.8min was observed in four extracts except in GU-4. The total phenolics contents was high in GU-4(3.38 g/100 g). ABTS radical scavenging was high in GU-5($EC_{50}$, 0.57 ug) and DPPH radical scavenging was high in GU-4($EC_{50}$, 2.66 ug). The extracts of GU-3, GU-4, and GU-2 were most potent in anti-mutagenicity activity against 1-NP, Trip-P-1, and Trip-P-2, respectively. GU-3 and GU-4 also showed most potent effect of anti-mutagenicity on 2-AA and AFB1, respectively.

• Korean journal of applied entomology
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• v.62 no.3
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• pp.139-147
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• 2023

Leaf-spray in vitro bioassays appraise new aphicidal formulations for managing deleterious plant-feeding aphids. The formulation may utilize alternative and integrated strategies. However, leaf spraying even under controlled conditions may affect aphid reproduction and mortality. This study examines leaf spray applications for optimum and reproducible aphicidal results using tobacco leaves overlaid on cotton fabric or water agar surfaces. Infestation of the undersides of tobacco leaves with nymphs of green peach aphids was used in the assays. Spray distance and volume were optimized using water-sensitive paper to ascertain the best surface coverage. Overlays of the leaves on water agar caused less mortality and greater reproduction than the use of cotton fabric. The relative humidity of the insect-rearing chambers changed with the watering regime for the insect - rearing chambers with cotton fabric; 60% relative humidity was optimal. Relative humidity was not affected by the concentration of agar in the water agar chambers. Applications of the chemical aphicidal standard, Sulfoxaflor, under the optimized conditions exhibited similar times for lethality although the rate was faster with leaves on the cotton fabric than on water agar. These studies establish reproducible and sensitive techniques for assessing the lethality and effects on reproduction of potential aphicidal products.