• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.6
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• pp.439-442
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• 2001

This study has been conducted from April 25, 1999 to June 25, 1999 in Jeju Province in order to determine the influence of seeding date on growth, yield and chemical composition of Kenaf (Hibiscus cannabinus L.) Delaying the seeding date from April 25 to June 25 decreased the plant height of Kenaf from 278.5 cm to 205.7 cm. As for the number of leaves, number of withering leaves, number of branches, and stem diameter decreased as the seeding date was delayed. As the seeding date was delayed, fresh forage yield decreased from 98.5MT/㏊ to 45.9MT/㏊, dry matter yield from 20.7MT/㏊ to 8.2MT/㏊, crude protein (CP) yield from 2.9MT/ha to 1.3MT/ha and total digestible nutrients (TDN) yield form 1l.6MT/㏊ to 5MT/㏊. However, both leaf yield and stem yield were nearly the same tendency. Delaying the seeding date from April 25 to June 25 increased crude protein contents of leaves from 21.5％ to 24.4％, crude fat contents from 5.2％ to 6.1％, nitrogen free extract (NFE) contents form 39.9％ to 41.2％ and TDN contents from 64.3％ to 69.7％. However, delaying seeding date decreased crude fiber contents from 20.8％ to 17.5％, and crude ash contents from 7.9％ to 7.0％. Based on the these findings, optimum seeding date for forage production of Kenaf seems to be about 25 April in atmospheric phenomena and volcanic ash soils of Jeju island.

• Journal of Sericultural and Entomological Science
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• v.35 no.1
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• pp.21-27
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• 1993

Yongchonppong is liable to withering of leaf and it is lowering leaf value for the feed. In this respect, covering of the vinylon gauze over the feed has been carried out in the branch rearing system to sustain leaf value as itself. The covering of the vintlon gauze over Yongchonppong marks 7% and 9% increment of cocoon yield in dry season, spring rearing season, as compared to the non-covering of the vinylon gauze over Kaeryangppong and Yongchonppong, respectively. There was no significant differences in cocoon shell percentages of them. In more humid environment than average relative humidity in Korea the rearing results of "Yongchonppong" was improved by covering with vinylon gauze after feeding compared with the non-covered rearing. However, the vinylon guage covering was not effective for improving the rearing results of "Kaeryangppong". No effect of the vinylon gauze covering was seen in the area where it frequently rains and raining season lasts. In case of the non-covering of the vinylon gauze, Yongchonppong reduces repidly in the first three hours of exposure to the air, as compared to Kaeryangppong. The water content reductions rate of Yongchonppong in 6 hours of exposure to the air marks 7% to so when the dry vinylon gauze cover and 17 to 26% when the wet vinylon gauze covers, as compared to 58.8% of it for the noncovering of the vinylon gauze.f the vinylon gauze.

• Korean Journal of Weed Science
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• v.31 no.4
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• pp.375-383
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• 2011

This experiment was carried out to confirm characteristics of macro granule (GG) for herbicidal efficacy by using remote-controlled aerial application (RCAA) to control annual and perennial weeds in rice paddy field, and phytotoxicity to rice and non target plants of formulation types. Herbicidal efficacy of GG applied by using RCAA was 93.6~96.6% in flooded direct sowing cultivation. There was no difference in phytotoxicity between the hand and the power applicator methods in terms of height, number of tiller and yield component. Herbicidal efficacy of GG applied by using RCAA was 92.7~97.3% in machine transplanting rice field. There was no difference in phytotoxicity between the hand and RCAA methods in terms of height, number of tiller and yield component. When suspension concentrate (SC) and GG were applied directly on Chinese cabbage, lettuce, cucumber, pepper, soybean and wild sesame, several symptoms of injury such as, the inhibition of growth, yellowish, leaf fall and withering was observed.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.618-627
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• 2015

Soil salinity is the most critical factor for crop production at reclaimed tidal saline soil. Subsurface drainage system is recognized as a powerful tool for the process of desalinization in saline soil. The objective of this study was to investigate the effects of subsurface drainage systems on soil salinity and corn development at Saemangeum reclaimed tidal saline soil. The field experiments were carried out between 2012 and 2014 at Saemangeum reclaimed tidal land, Buan, Korea. Subsurface drainage was installed with four treatments: 1) drain spacing of 5 m, 2) drain spacing 10 m, 3) double layer with drain spacing 5 m and 10 m, and 4) the control without any treatment. The levels of water table showed shorter periods above 60 cm levels with the deeper installation of subsurface drainage system. Water soluble cations were significantly greater than exchangeable forms and soluble Na contents, especially in surface layer, were greatly reduced with the installation of subsurface drainage system. Subsurface drainage system improved biomass yield of corn and withering rate. Thus, the biomass yield of corn was improved and the shoot growth was more affected by salinity than was the root growth. The efficiency of double layer was not significant compared with the drain spacing of 5 m. The economic return to growers at reclaimed tidal saline soil was the greatest by the subsurface drainage system with 5 m drain spacing. Our results demonstrated that the installation of subsurface drainage system with drain space of 5 m spacing would be a best management practice to control soil salinity and corn development at Saemangeum reclaimed tidal saline soil.

• Journal of Environmental Impact Assessment
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• v.30 no.6
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• pp.361-379
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• 2021

About 10% of trees damaged by the development projects are to be transplanted when conducting the Environmental Impact Assessment. However, various problems have been raised during transplantation. In this study, we confirm the stakeholder's perceptions of the problems that occur during transplantation. The survey was conducted from October 9 to 25, 2020. Among the stakeholder groups, 36 respondents participated in the consulting institute group, 44 from the review institute group, and 83 from the developer·agency group (total of 163). All three groups responded that it was necessary to transplant some of the damaged trees even if the development charge increased because the damage caused by the development project was serious. The most serious problem was 'high mortality'. The response rate was high that all three groups should plant the same species with the same quantity as an alternative method in case of withering. In order to reduce the mortality rate, small-sized trees were transplanted and transplanted trees were expanded to include planted species and landscape trees. In addition, the number of transplanted trees was high in response to calculating the transplantratio to the number of native tree damaged. The percentage of respondents who said that it was necessary to allocate a separate manager was also high. The results will be used as basic data to improve problems that occur during transplantation of damaged trees.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.278-278
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• 2022

Recently, the yield potential of high yield Tongil-type rice varieties has greatly increased, reaching 817kg/10a(Geumgang No.1). Moreover, in order to promote rice consumption and strengthen the competitiveness of the rice processing industry, the R&D of high yield Tongil-type rice varieties for each processing purpose, such as rice noodles, grain feed and industrial materials, has been continuously carried out. However, because Tongil-type rice varieties or lines are generally very vulnerable to cold damage, cold tolerance test can be said to be absolutely necessary to improve the cultivation safety. This study is the result of the seedling and field cold tolerance characteristic tests carried out in 2021 of high yield Tongil-type rice breeding lines. For the cold tolerance characteristic test of seedlings, total 303 high yield rice breeding lines for processing were treated in cold water of 13℃ and irrigation depth of 4cm for 10 days from the third-leaf age, then it was evaluated by comparing the degree of discoloration and withering with the checked varieties(Boramchan, Hanahreum No.2). Also, for the test of field, total 186 high yield rice breeding lines for processing were treated in cold water of 17℃ by keeping pouring day and night from 30 days after transplanting to ripening stage, then it was evaluated by comparing the degree of discoloration, delay of heading, shortening rate of stem length and percent of fertile grain etc. with the checked varieties. And the cold tolerance evaluative criteria were classified as strong(1~3), medium(4~6) and weak(7~9) in overall cold tolerance. (Seedling test) As for the degree of cold tolerance of the check variety, 'Boramchan' and 'Hanahreum No.2' showed a response of 'medium' and 'weak', respectively. However, there was no 'strong' line in the high yield rice breeding lines, 2 lines showed a 'medium' response, and 301 lines showed a 'weak' response. Therefore, except for a few lines(0.7%), most lines(99.3%) showed a 'weak' response. (Field test) In terms of the overall cold tolerance of the check variety, both 'Boramchan' and 'Hanahreum No.2' showed a 'medium' response. Similarly, there was no 'strong' line in the case of high yield rice breeding lines, 20 lines showed a 'medium' response, and 166 lines showed a 'weak' response. Therefore, except for some(10.8%) lines, most(89.2%) lines showed a 'weak' response. From the above results, we selected about 100 individuals with less seed shattering and degeneration of the ear tip, and with a relatively high percent of fertile grain, and are continuing to select lines with improved cold tolerance in the F4~F5 group in this year. As such, most of the Tongil-type rice varieties have poor cold tolerance and thus have low cultivation safety at low temperatures. However, it is important to select improved lines through generational progress because there are some lines that still have a certain level of cold tolerance among them.

• Journal of Korean Society of Forest Science
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• v.90 no.4
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• pp.565-572
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• 2001

The spatial genetic structure of Needle fir(Abies holophylla Max.) seedlings on forest gap within a Needle fir forest at Mt. Odae in Korea was analyzed on the basis of ISSR(inter-simple sequence repeats) marker analysis. The gap size was $1,500m^2(50m{\times}30m)$, and we sampled 416 one- or two-year-old seedlings by 2m intervals. Some trees at the upper crown layer except Needle firs and all trees at the middle and lower crown layers were removed, and Needle firs at the upper crown layer showed very weak growth strength or to be withering to death. The results of spatial autocorrelation using 31 polymorphic ISSR markers revealed that it was genetically homogeneous within spatial distance of 15.6m and the randomness of genetic distribution was from 15.6m to 31.2m. The genetic patch size of seedlings in forest gap might be restricted by the density of mother trees, making allow for the average height of adult Needle firs, the seed dispersal area, and the average distance between adults. For the directionality of seedling distribution, we investigated the variography using 'genetic configuration' which was the value of configuration in Multidimensional Scaling by genetic distance. In directional variogram, the increment of spatial distance from East to West direction was inversely proportional to genetic homogeneity. We presumed that this anisotrophy of seedling distribution at this forest gap resulted from the directionality of seed dispersal rather than the difference of fecundity between mother trees or the microhabitat variation, taking the evenness of forest floor condition, a vast seed production and the random distribution of seedlings at the studied site into consideration.

• Korean Journal of Environment and Ecology
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• v.26 no.5
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• pp.707-718
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• 2012

This study was conducted to monitor 4 years of changes in the vegetation structure starting from 2007 when restoration began and propose vegetation management ideas for the riparian ecological restoration areas in the purchased land around Nakdonggang(River). The study was conducted in each of 15 locations ($208,342m^2$) in the riparian ecological restoration areas in November 2007, September 2008, October 2009 and September 2010. The analysis results of the changes in planting species and population showed that, in the case of trees, Acer pseudo-sieboldianum, Quercus acutissima, Acer ginnala, Quercus aliena, Quercus variabilis indicated relatively little changes in their numbers and Quercus dentata, Cornus walteri, Morus alba, Styrax obassia, Sorbus alnifolia var. macrophylla indicated a 100% withering rate. Most shrubs withered due to the oppressive pressure of herbs and climbing plants. The planting density decreased over 4 years on average 28 plants/$100m^2$ to 20 plants/$100m^2$ to 16 plants/$100m^2$. Shortly after the restoration, The the amount of growth was reduced by restoration stress. however as time goes on after the restoration tended to stabilize. The changes in the basal area showed a decrease from $507.1cm^2/100m^2$ in 2007 right after restoration to $301.8cm^2/100m^2$ in 2008 and afterwards showed an increasing trend by going to $324.9cm^2/100m^2$ in 2009 and $372.7cm^2/100m^2$ in 2010. To improve the planting structure of the riparian ecological restoration area, the selection of tree species that have been considered for soil moisture and the differentiation of suitable planting structures that have been considered for local conditions were needed.

• Korean Journal of Soil Science and Fertilizer
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• v.13 no.1
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• pp.39-44
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• 1980

To study the effects of sulfur dioxide on the plant; Barly, wheat, soybean sweet potato, cucumber, egg plant, red pepper, tomato, lettuce, water melon, castor bean, grape and lily were exposed to the different levels of sulfur dioxide gas(0.1, 0.25, 0.50, $1.0mg/{\ell}/hr$) The symptoms of damage, ratios of destroyed leaf, sulfur content and absorption amounts of the gas by leaves were investigated 1. According to the increasing concentration of the gas ratios of destroyed leaf were increased in all plants. The ratios of destroyed leaf were shown by egg plant at $0.1mg/{\ell}/hr$ of $SO_2$ were 30 percent, and no visible injuries were shown by the wheat potato, castor bean, water melon, lily at $0.25mg/{\ell}/hr$. 2. Gray and red brown spots between the vein nerve shown by barly and wheat leaf; leaf burn by soybean, potato, sweat potato, castor bean, egg plant, red pepper, tomato and grape; leaf withering from the leaf tips by the lettuce, water melon, lily. 3. The volums of the gas absorption by cucumber, egg plant, red peper, castor he an were more than $10{\ell}/hr$, however less than $2{\ell}/hr$, be lettuce, water melon, grape, barly and wheat. 4. According to the increasing concentration of sulfur dioxide gas, sulfur contents in leaf were increased in all plants, however volums of absorption gas were decreaed. 5. According to the increase of sulfur content in leaf, ratios of destroyed leaf were increased. 6. Positive correlation was shown between total and water soluble sulfur content in leaf.

• Journal of the Korean earth science society
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• v.34 no.6
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• pp.515-523
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• 2013

The eastern coast of South Korea is expected to be damaged by volcanic ash when Mt. Baekdusan volcano erupts. Even if the amount of volcanic ash is small, it can be fatal on the agricultural sector withering many plants and causing soil acidification. Thus, in this paper, we aim to estimate agricultural losses caused by the volcanic ash and to visualize them with Google map. To estimate the volcanic ash losses, a damage assessment model is needed. As the volcanic ash hazard depends on the kind of a crops and the ash thickness, the fragility function of damage assessment model should represent the relation between ash thickness and damage rate of crops. Thus, we model the fragility function using the damage rate for each crop of RiskScape. The volcanic ash losses can be calculated with the agricultural output and the price of each crop using the fragility function. This paper also represents the estimated result of the losses in Gangwon province, which is most likely to get damaged by volcanic ashes in Korea. According to the result with gross agricultural output of Gangwon province in 2010, the amount of volcanic ash losses runs nearly 635,124 million wons in Korean currency if volcanic ash is accumulated over four millimeters. This amount represents about 50% of the gross agricultural output of Gangwon province. We consider the damage only for the crops in this paper. However, a volcanic ash fall has the potential to damage the assets for a farm, including the soil fertility and installations. Thus, to estimate the total amount of volcanic ash damage for the whole agricultural sectors, these collateral damages should also be considered.