• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.157-162
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• 2002

The efficient timer-controlled irrigation and the favorable fruiting position were investigated far highly quality melon fruits from Feb.18 to July Si 1999. The nutrient solution was supplied either at every hour from 6：00 to 18：00 (T-1) or at 6：00, 8：00, 10：00, 11：00, 12：00, 12：30, 13：00, 13：30, 14：00, 14：30, IS：00,16：00, and 17：00 (T-2). A fruit was set at the first node of the fruit bearing branch from the 10, 12, or 13th node of the main stem. Pot weight was maintained at almost n constant level, regardless of the daily integrated solar radiation in T-2. Soluble solids content (SSC) and fresh weight of fruit were not significantly different among the irrigation treatments at each harvesting time. At the first harvest, SSC and fresh weight of fruit were not significantly different between the fruiting positions within the irrigation treatment. At the second harvest, SSC was higher in T-2 than T-1. The SSC was low in the fruit of the loth node in T-1, while it was not significantly different between fruiting positions in T-2. Fruit fresh weight was the highest at the 12 and 13th nodes in T-1, and the 13th node in T-2. Fresh and dry weights of leaf except petiole, regardless of harvesting time, increased as the node position was higher, The higher the fruiting position was, the lower the leaf weight was. Therefore, it is recommended to irrigate more frequently during the mid-noon. Fruits can be harvested earlier at the lower nodes in the spring crop production.

• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.205-216
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• 2002

This study was conducted to examine the effect of long-day (LD) period before short-day (SD) treatment on the vegetative growth of greenhouse-grown cut chrysanthemum cv. Reagan Improved at Wageningen Agricultural University, The Netherlands. Rooted cuttings of cut chrysanthemum cv, Reagan Improved were transplanted on 6th, 13th, 20th of September and all of them were treated with LD before SD treatment on 27th of September, The periods from transplanting until final harvest were 70, 77, and 84 days for 1, 2, and 3 week-LD treatment, respectively. The final plant height increased in the plot of 3 week-LD period and decreased in the plot of 1 week-LD period before the SD treatment. Total fresh weight and the leaf area were increased more in the plot of 3 week-LD period than that of 1 week-LD period, but the absolute growth rate after SD treatment was the same on plant growth rate and increase of the number of leaves in all treatments. The final dry matter production (g.m$^{-2}$ ) was increased more in the plot of 3 week-LD period than that of 1, 2week-LD period before SD treatment. Plant height and fresh weight were followed by the condition of LD period. In addition, dry mass production was highest in 3 week-LD period.

• Korean Journal of Medicinal Crop Science
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• v.5 no.4
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• pp.314-317
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• 1997

This study was carried out to determine the effect of various fertilizer levels on the growth and yield of Scutellaria baicalensis Georg cultivated after the barley in the southern coastal areas of Korea under the non-mulching condition by direct sowing culture. The flowering date of medium dressing plot $(N\;:\;P_2O_5\;:\;K_2O=9\;:\;13.5\;:\;9 kg/10a)$ and heavy dression plot $(N\;:\;P_2O_5\;:\;K_2O=12\;:\;18\;:\;12kg/l0a)$ were July 23. The flowering date of the medium and the heavy dressing plot was delayed by 3days compared with that of non-fertilizing plot. The growth characteristics such as stem length, diameter of main stem, number of branch per plant, main root length, main root thickness and dry weight of stem leaves were more increased at medium dressing plot than that of other fertilizer levels. The root dry weight of in Scutellaria baicalensis Georg cultivated after barley was highest at the fertilizing plot of N, $P_2O_5\;:\;K_2O$ = 9 : 13.5 : 9kg/10a. The dried-root yield was 178kg in medium dressing plot, 167kg in standard dressing pot, and 126kg in non-dressing plot. The dried-root yield of medium dressing plot was 7% and 41% higher than that of standard dressing pot and non-dressing control plot, respectively.

• Korean journal of applied entomology
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• v.40 no.4
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• pp.327-335
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• 2001

In order to establish a whitefly control system using conventional groups of insecticide(carbamate, organophosphorus and pyrethroid insecticides), three alternative application methods were designed on the medium growth stage of cucumber. To discriminate the effectiveness of these sequences observed were the residual activity of insecticides, frequency of insecticide applications, residue of insecticides in cucumber leaves, development of insecticide resistance in whitefly, and yield of fruits. Spraying furathiocarb, a carbamate insecticide, was very effective in reducing the frequency of application for the control of white flies. The effectiveness of furathiocarb was enhanced by the potentiation process to carbofuran, the long residual activity, and the lower development rate of insecticide resistance. Methion, an organophosphorus insecticide, did not show resistance development after successive use but resulted in short residual activity. However, other organophosphates, profenofos and phenthoate, lost their activity by the resistance development. Decreasing activity was common to pyrethroids, deltamethrin and zetacypermethrin due to resistance. From these results it could be drawn a conclusion that furathiocarb, a carbamate insecticide, was the most desirable among conventional insecticide groups for the management of greenhouse whitefly population on the cucumber. To prevent an outbreak of the insect pest by various cause, it was recommended to choose acetamiprid, a nicotinoid, which showed very good control efficacy to the resistance insects to conventional insecticides.

• Korean Journal of Environmental Agriculture
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• v.6 no.1
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• pp.38-43
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• 1987

This study was carried out to investigate the effect of ozone gas on paddy rice at the different nutrition levels. Jinjubyeo variety of rice plant was exposed to 0.3 ppm ozone gas for 3 hours. It was cultivated at three different application levels, optimum, -50%, and +50% of optimum of nitrogen, phosphorus, and potassium, respectively. After ozone gas fumigation, percentage of damaged leaf, malondialdehyde contents, activity of peroxidase, and nutrient contents of rice plant were observed. The results obtained are as follows. 1) Percentage of damaged leaf was increased at the both additional 50% application of nitrogen and 50% reduction of potassium. 2) Malondialdehyde contents of leaves were increased with the ozone gas exposure. 3) Percentage of damaged leaf was increased at the lower level of $K_2O/N$ ratio in leaves. 4) Nitrogen, phosphorus, and potassium contents in rice leaves were decreased with the ozone gas exposure. 5) The peroxidase bands on gel in electrophoresis were changed by the ozone gas exposure.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.2
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• pp.220-227
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• 1997

Water deficit stress during early soybean[Glycine max (L.) Merrill] growth stage is the most important environmental factor limiting productivity. Eight soybean genotypes were grown in replicated pot under well-watered(control: near 0 bar) and drought(-5 and -10 bars) conditions. Soybean plants were subject to drought stress for 20 days at 10 days after seed emergence. Significant genotypic variation was observed for leaf area(LA) and total dry weight (TDW). At the end of water stress, LA and TDW of Hwanggeumkong and Paldalkong, which had large LA in the non-stressed control, were more sensitive to water stress than those of the other cultivars, while those of Suwon 93 with small LA were insensitive. Leaf proline and abscisic acid(ABA) contents increased after water stress. However, changes in proline and ABA contents were not consistently related to the changes in LA as affected by water stress. As the soil water potential decreased, the yield reduction of Hodgson 78 showing large decrease in LA and TDW in response to water deficit was severe when compared to that of Baegunkong with small decrease in LA and TDW. Relatively greater yield stability and higher average yield across soil water potential were observed in Baegunkong. Of specific interest was the small reduction in yield of Paldalkong in spite of its significant decrease in LA and TDW.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.89-93
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• 1997

To determine the optimum levels of soil phosphorus and potassium for the carrot growth and to investigate the relationship between the quality of carrot root and, P and K contents in soil, carrot was planted in $1m^2$ bottomless pot with five levels of P and K. Maximum root weight was harvested in the plots with 425mg/kg of available P as $P_2O_5$ and $0.72cmol^+/kg$ of exchangeable potassium as K in soil at carrot shoot elongation stage. The concentrations of P and K in harvested carrot root were high in the plots with 359-396 mg/kg of available $P_2O_5$ and $0.79-0.87cmol^+/kg$ of exchangeable K. Sugar content in carrot root increased to available $P_2O_5$ 284 mg/kg in soil and it decreased as soil potassium increased.

• Korean Journal of Weed Science
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• v.5 no.1
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• pp.24-34
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• 1985

To estimate the fundamental situation of weed emergence and it's competition to paddy rice (critical competition period and threshold level) in the southern paddy area in Korea, two rice cultivars (Pungsanbyo and Tongjinbyo) under two cropping periods (Mono- and After-barley-cropping) were experimented. As a result, the dominant weed species (Monochoria vaginalis and Scirpus juncoides Roxb.) and the better emerging conditions (rather at the monocropping and cv. Punsanbyo) were identified. Also, the main components of yield decrease (25-55% of the weed-free check) of both cultivars as affected by weed competition were the number of spikelets, panicle and ripening rate in monocropping, and the ripening rate and grain weight in after-barley-cropping, respectively. Under the situation of combinated dominance with Monochoria v. and Scirpus j. among others, the duration of critical competition periods was enlarged.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.6
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• pp.383-387
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• 2004

Effects of oyster shell powder as a liming material were investigated in an apple orchard. Soil texture of the apple orchard was silty clay loam (Upyeong series with 7% of slope) and topsoil pH was 5.6. Treatments of 1,590 kg oyster shell powder $ha^{-1}$ and calcium-magnesium carbonate as much as oyster shell powder were included in the experiment. With treatments of oyster shell powder and calcium-magnesium carbonate, the length, number and diameter of new branches and the diameter of main, secondary and side branches increased in comparison with control. With oyster shell powder application, soil pH increased from 5.6 to 6.8 at the harvest. In addition, it increased exchangeable Ca from 2.6 to $4.2cmol_c\;kg^{-1}$. But it didn't make any difference in chlorophyll, sugar and malic acid contents. The apple weight per fruit of oyster shell powder application was 9 g more than that of control. Apple yield was highest ($37,000kg\;ha^{-1}$) in the oyster shell powder treatment, and the yield increase was significantly different at 5% level LSD. We concluded that the oyster shell powder can be an alternative of lime and effective to restore soil nutrient balance in apple orchard soil.

• Korean Journal of Organic Agriculture
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• v.7 no.2
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• pp.179-188
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• 1999

The effects of earthworm casts as a plant growth media on the growth of orchardgrass seedlings and the changes of physico-chemical properties in worm casts mixture soils were investigated during the growth period of 1998. Worm casts were mixtured with vermiculite, perlite and peat moss, and mixture ratios of worm casts with commercial recommended soil were 100:0(control), 75:25, 50:50, 25:75, and 0:100, respectively. The results were obtained as follows; 1. Plant length(PL) was increased in higher mixture ratios of worm casts and peat moss than those of other mixture ratios of commercial recommended soils. 2. Number of tillers(NT) were significantly increased in mixture ratios of worm casts and peat moss(50:50) and 100% of vermiculite. 3. Root length(RL) was significantly differences between mixture ratios at the worm casts, and the highest value was obtained at all mixture ratios of worm casts and perlite. 4. Dry weight of leaf(LW) was not significantly differences at mixture ratios of 50:50 in all treatments. Especially, between the mixture ratios of worm casts with peatmoss(25:75) and peat moss(75:25) were not significantly differences in dry weight of leaf(LW). The highest value of dry weight of leaf(LW) was obtained at mixture ratios of peat moss and worm casts. 5. Dry weight of tillers(SW) was not significantly differences at mixture ratios of 50:50 in all treatments, and peat moss(75:25) and vermiculite(75:25), respectively. 6. biological yield(BY) at all treatments were increased by yield components of dry weight of tillers(SW), dry weight of root(RW) and length of root(RL). 7. The biological yield of orchardgrass seedlings was greatly increased with mixture ratios of worm casts and peat moss over the 50%.