• Journal of Climate Change Research
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• v.9 no.3
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• pp.293-302
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• 2018

This study was carried out to provide basic information on efficient preservation and management of an Abies koreana forest through analyzing the ecological characteristics by slope in Seseok, Mt. Jirisan. Soil moisture content at southern and northern slopes was 29.9% and 21.7%, respectively, and there was no significant difference among soil properties between southern and northern slopes. The importance value of A. koreana in the southern and northern slopes was high for tree and subtree layers, respectively. It is noteworthy that many seedling and saplings of A. koreana were present on the southern slope. The species diversity was 0.413 for the tree layer, 0.632 for the subtree layer, and 0.609 for the shrub layer on the southern slope and 0.396 for the tree layer, 0.783 for the subtree layer, and 1.215 for the shrub layer on the northern slope. Evenness and dominance ranged from 0.371 to 0.609 and 0.629 to 0.391 on the southern slope and from 0.380 to 0.968 and 0.620 to 0.032 on the northern slope, respectively. The mortality of A. koreana was 9.6% on the southern slope and 24.4% on the northern slope, a distinct difference between the slopes. The mortality type at two slopes was the highest proportion of standing dead. Annual mean tree ring growth of A. koreana on the southern slope (1.76 mm/yr) was higher than that on the northern slope (1.64 mm/yr).

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.1009-1020
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• 1996

Direct-seeded rice can have comparable yield with transplanted rice if its inherent problems can be solved. It is a labor-saving technology and can significantly reduce production cost because seedling nursery , pulling , and transplanting are omitted. Turnaround time between cropping is reduced hence the possibility of a third annual crop. But direct-seeded rice is very vulnerable to pest attack (by birds, rats, and golden snails), desiccation, weed infestation, and prone to lodging resulting to unstable crop establishment and inconsistent yield. These problems can be solved by anaerobic seeding (sowing pre-germinated seeds under the soil). It requires precise seed placement into the soil to optimize its benefits. We developed a four-row anaerobic direct seeder (US $ 200 commercial price) for this purpose . It consist of a structural framework mounted with a drum -hopper metering device, flotation type drivewheels, spring-loaded and adjustable furrow closers, and furrow open rs, and a plastic rainguard. It can sow in line pre-germinated seeds into the soil thus permitting the use of mechanical weeders for a chemical-free weed control. Its performance was comparable with the Japanese two-row anaerobic seeder (costing US$400) in terms of seed placement and crop establishment. It was tested with five cultivars. Seeding rate varied from 38 kg/ha to 80kg/ha. Crop establishment ranged from 64 to 99 percent while grain yield varied from 3.0 t/ha to 5.4t/ha. A six-row anaerobic seeder was also developed and adapted to a powertiller for increased capacity , field efficiency , and easier operation. The anaerobic seeder is useful to farmers shifting to direct seeding to reduce rice production cost and to researchers conducting agronomic studies in direct-seeded rice. Blueprint of the machine is available free of charge from IRRI.

• Korean Journal of Environmental Agriculture
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• v.42 no.3
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• pp.177-183
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• 2023

Rendering, is attracting attention as a technology that can stably and quickly process livestock carcasses. However, large amounts of livestock carcass solid residues are discharged in this process and limited methods are available for recycling them. In this study, rendered animal carcass solid residues were pyrolyzed to produce carbonized materials (350℃; RACR-C) and their chemical properties were investigated. Further, RACR-C were applied to cabbage cultivation for investigating their crop growth characteristics and soil improvement effects. RACR-C contained large amounts of fertilizer components such as nitrogen and phosphorus, and showed no toxic effects on the seedling growth of crops. The content of water-soluble nutrients released from RACR-C under the reaction time increased rapidly within 30 min, but was insignificant compared to the total content. Thus, most fertilizer components in RACR-C were not readily soluble in water. The optimal application amount for applying RACR-C to cabbage cultivation based on the changes in cabbage growth, inorganic content, and soil chemistry was 200 kg/10a. Overall, pyrolysis of solid residues after rendering livestock carcass to produce carbonized material as a soil improver is an effective method to recycle the waste discharged from the rendering process.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.1
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• pp.26-33
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• 1996

A nutrient solution culture experiment was conducted in the greenhouse at Suwon Campus. Kyung-Hee University from May 23 to July 11. 1995, to determine the effects of potassium application on seedling growth of Kwanganok and Hwengsungok cultivars of corn. Potassium was treated with four different levels, which are 0.248.496 and 744ppm for treatments without potassium (-k), standard potassium concentration (K), double(2k) and triple (3k) of standard potassium concentration, respectively. Plants were harvested at weekly interval for seven weeks. at which time plant height, leaf area and dry matter yield of corn seedling were measured, only chlorophyll content was taken for five weeks from three week after planting. Seedlings growth of Kwanganok and Hwengsungok cultivars was greatly retarded from planting to harvesting time in 3k treatment. The plant height, leaf area and dry matter yield of both cultivars during the whole period were decreased in order of K>2F>-K>3K, but dry matter yield of Kwanganok cultivar was decreased in order of 2K>K>-K>3K. Chlorophyll content of Kwanganok and Hwengsungok cultivars was irregularly fluctuated during growing period. but generally highest in K treatment and lowest in 3k treatment. The crop growth rates of seedlings of both cultivars were slow until the 3rd week after planting. but very fast thereafter. In general, CGR of both cultivars was higher in K and 2k treatments than -k and 3k treatments.

• Journal of Korean Society of Forest Science
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• v.58 no.1
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• pp.34-40
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• 1982

Main consideration of this trial is to know whether the planting work should be possible to do not only in the early spring but also in the summer or autumn, for giving the guide to get the work plan and to broaden the employing season of the skilled forest worker. Seedling of Pinus koraiensis, Larix leptolepsis, Pinus rigida, Pinus rigida${\times}$ P. taeda(wind) and Chamaecyparia obtusa as the test species had been planted in 15 days interval from the middle of March to the end of November. The seedling survival was investigated in the spring time of coming year because the winter damage could be problems. At the same time the climate data was measured daily and the shoot growth of test species were also measured in other near plantation at 15 days interval to know the influence to survival. From these results the spring and autumn planting is showing the good survival and the summer planting seems to give the difficulties. The spring planting in the southern temperate zone could be stared earlier as the end of February or beginning of March because the soil temperature are increasing up more $5^{\circ}C$ from this time. But the summer planting from the beginning of May until the end of August in better to avoid with excluding specially the good season of rainfall distribution because of the shoot growth of green confer seedling and the leave sprouting of Larix leptolepsis are so vigorously growing up from the begining of May and its wood structure is too weak to compensate the water loss. But among the test species Pinus koraiensis and Chamaecyparis obtusa have more possibility to plant in the summer season. The autumn planting seems to be very reasonable to accept newly in the trial region. This may be the reasons of still high soil temperature to grow the seedling root and of hardened school to resist from the dry winter wind. But it will be carefully that the strongly exposured site could be to avoid for the autumn planting in case of specially Pinus rigida${\times}$P. taeda and Chamaecyparis obtusa. From these discussion the guide table 1 for planting season with the test species is proposed and can be used for planing and employing in the trial zone.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.365-372
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• 2011

This study aimed to examine foundational data for container seedling production with the subject of Daphniphyllum macropodum community in Mt. Naejang National Park. To achieve the goal, it investigated the growth characteristics of young tree seedlings growing in places with different light intensity environment. Regarding the growth environment of Daphniphyllum macropodum community, it was typical heavy rain summer climate, and the soil was silt loam with the organic content as 11.42~15.61%, total nitrogen as 0.50~0.76%, cation exchangeable capacity (C.E.C) as 18.92~23.32 cmol/kg, and pH as 4.85~5.58. About light intensity environment changed by research plots, relative transmittance of solar radiation was 71~76% in plot A, 37~42% in plot B, 65~70% in plot C, and 28~33% in plot D. The seedlings tended to be intensively distributed either under the crown of their mother tree or in the slope site, and plot A and C where light intensity environment is relatively more favorable showed 1,550 tree/ha and 1,250 tree/ha. Total biomass production of Daphniphyllum macropodum seedlings was 5.37 g in plot A and 5.29 g in plot C, so they were higher than 4.42~4.51 g in plot B and D with relatively less favorable light intensity environment. The T/R ratio was 1~2, leaf area rate was $139.71{\sim}183.50cm^2{\cdot}g^{-1}$, leaf area ratio was $39.68{\sim}60.66cm^2{\cdot}g^{-1}$, and leaf dry weight ratio grew higher in the range of $0.28{\sim}0.33cm^2{\cdot}g^{-1}$ as the intensity of radiation became less. It is thought that in the generation and growth of Daphniphyllum macropodum seedlings, the intensity of light has more effects than the organic content in soil. And it is also thought that in the application of container seedlings production, light environment management over 65~70% to full sun light intensity will affect significantly the initial growth of Daphniphyllum macropodum.

• The Korean Journal of Ecology
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• v.26 no.1
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• pp.5-12
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• 2003

Seed germination rate and seedling growth were measured on 6 different species(Phytolacca americana, Eupatorium rugosum, Rumex acetocella, Echinochloa crusgalli, Cassia mimosoides var. nomame, Setaria viridis) treated with leaf extract of E. rugosum. Total phenolic compound and heavy metal were analyzed on leaf and soil with and without E. rugosum. The growth of P. americana seedlings were stimulated by 10% and 25% of E. rugosum water extract treatment. The content of total phenolic compounds in soil was lower than that of leaf extract, and 25% was confirmed as threshold concentration in natural systems because the total phenolic compounds were not significantly different between the control soils and the soil treated with 10%, and 25% extract. Total phenolic compound concentrations of the leaf extracts were highest (1.66 mg/l) with E. rugosum grown under the Quercus forest canopy and lowest (1.09 mg/l) for the plant grown in the mixed forest edge. Leaf extracts of plants selected in different sampling sites (Forest interior, Forest edge, under Pinus Canopy and Quercus Canopy) were significant, while soil extracts were not. Seed germination of R. acetocella and S. viridis were significantly inhibited at over 50% concentrations of E. rugosum, but C. mimosoides var. nomame was not affected at any concentration. The radicle and shoot growth of the native species group were reduced two times more than those of the exotic species group by the treatment of extracts. Especially, the seed germination percentage and dry weight of E. rugosum were greater than those of the control group by treatments with extracts of 10% and 25%. Analysis of aqueous extracts from E. rugosum by HPLC identified 6 phenolic compounds: caffeic acid (460.9 mg/l), benzoic acid (109.7 mg/l), protocatechuic acid (7.3 mg/l), ρ-hydroquinone (6.0 mg/l), cinnamic acid (2.7 mg/l) and hydroquinone (0.23 mg/l). The seed germination of P. americana was also inhibited dramatically by protocatechuic acid and cinnamic acid even though the content of caffeic acid (460.9 mg/l) was the highest among analyzed phenolic compounds. The heavy metal content of soil without A. altissima was higher than that of soil with E. rugosum. Particularly, Al, Fe and Mn was considerably high and most of the heavy metal were accumulated in leaves where a high level of total phenolic compounds was found.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.4
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• pp.183-189
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• 2000

This study was carried out to analyze ecophysiological responses for seedling of Quercus serrata, Quercus mongolica and Quercus variabilis that are the typical species of deciduous broadleaved forests in Korea. And executed experiments in the climatic control room to provide necessary information to ecological forest management and methods of natural regeneration through the analysis of seedling responses. The details of experimental analysis were growth processes of 4 months after seeding that vary with the condition of three light intensity[relative light intensity(RLI) 8%, 20%, 52%] and three soil moisture[water suction(WS) Ψ=100 hPa, Ψ=280 hPa, Ψ=330 hPa] gradient, growth factors after harvesting and the nutrition condition of leaves. The results of this study are followings: 1) Early growth was prosperous after germination for the species which have more weight of acorn. 2) The formation of lammas shoot was favourable with Q. variabilis and Q. mongolica. And the rate of the occurrence was the highest in the RLI 20%, and it was remarkably reduced in the RLI 8%. 3) As the height growth of seedling of all 3 species were greater in the RLI 20% and 8% than that of the RLI 52%, they showed strong shade tolerance. 4) The increase of light intensity promoted the diameter at root collar growth, and development of main and lateral roots with all 3 species. 5) It showed that the increase of light intensity in the experimental radiation condition raised special leaf area weight(mg/cm$^2$) and leaf area productivity(mg/cm$^2$). Consequently, these resulted in the increase of leaf thickness and total dry biomass per the unit area of leaf. 6) As the increase of light intensity, the minerals contents of leaves such as N, P and K were lowered, and the increase of soil moisture resulted in the increase of P, K, Ca and Mg.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.4
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• pp.283-291
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• 2000

The beneficial effects of mycorrhizal fungi on plant growth has largely been attributed to higher uptake of P and other mineral nutrients. However, the effects of mycorrhizal colonization on uptake of mineral nutrients are conflicting in various past investigations. This study was carried out to investigate the effect of P application rate on mycorrhizal colonization and nutrient uptake of Poncirus trifoliata (trifoliate orange) seedlings grown in non-cultivated volcanic ash soil of Cheju island. Five levels of P (40, 573, 1,106, 1,373. $1,640mg\;P\;kg^{-1}$) were applied with double superphosphate. Seedlings inoculated with mycorrhizal fungi were grown for 5 month in a greenhouse. As the level of P application increased, mycorrhizal colonization in the seedlings decreased, and the colonization was significantly reduced when available P was higher than $150mg\;P\;kg^{-1}$ levels. There was a significant correlation between mycorrhizal colonization and P uptake by trifoliate orange seedlings at lower P applications. The effectiveness of mycorrhiaze on P uptake was more significant at lower P applications. Uptake of N, K, Ca, Mg an Zn by trifoliate orange seedlings also increased as mycorrhizal colonization increased, but mycorrhizae could not enhance the uptake of Cu by trifoliate orange seedlings in volcanic ash soil of Cheju island.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.s02
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• pp.66-80
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• 1989

Salt injury in rice is caused mainly by the salinity in soil and in the irrigated water, and occasionaly by salinity delivered through typhoon from the sea. The salt concentration of rice plants increased with higher salinity in the soil of the rice growing. The climatic conditions, high temperature and solar radiation and dry conditions promote the salt absorption of rice plant in saline soil. The higher salt accumulation in the rice plant generally reduces the root activity and inhibits the absorption of minerals of rice plant, resulting the reduction of photosynthesis. The salt damages of rice plant, however, are different from different growth stage of rice plants as follows: 1. Germination of rice seed was slightly delayed up to 1.0％ of salt concentration and remarkably at 1. 5％, but none of rice seeds were germinated at 2.5％. This may be due to the delayed water uptake of rice seeds and the inhibition of enzyme activity, 2. It was enable to establish rice seedlings at seed bed by 0.2％ of salt concentration with some reduction of leaf elongation. The increasing of 0.3％ salt concentration caused to the seedling death with varietal differences, but most of seedlings were death at 0.4％ with no varietal differences. 3. Seedlings grown at the nursery over 0.1％ salt, gradually reduced in rooting activity after transplanting according to increasing the salt concentration from 0.1％ up to 0.3％ of paddy field. However, the seedlings grown in normal seed bed showed no difference in rooting between varieties up to 0.1％ but significantly different at 0.3％ between varieties, but greatly reduced at 0.5％ and died at last in paddy after transplanting. 4. At panicle initiation stage, rice plant delayed in heading by salt damage, at meiotic stage reduced in grains and its filling rate due to inhibition of glume and pollen developing, and salt damage at heading stage and till 3 weeks after heading caused to reduction of fertilization and ripening rate. In viewpoint of agricultural policy the overcoming strategy for salt injury is to secure sufficient water source. Irrigation and drainage systems as well as underground drainage is necessary to desalinize more effectively. This must be the most effective and positive way except cost. By cultural practice, growing the salt tolerant variety with high population could increase yield. The intermittent irrigation and fresh water flooding especially at transplanting and from panicle initiation to heading stage, the most sensitive to salt injury, is important to reduce the salt content in saline soil. During the off-cropping season, plough and rotavation with flooding followed by drainage, or submersion and drainage with groove could improve the desalinization. Increase of nitrogen fertilizer with more split application, and soil improvement by lime, organic matter and forign soil addition, could increase the rice yield. Shift of trans-planting is one of the way to escape from the salt injury.