• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.3
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• pp.205-216
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• 1998

In order to investigate the short-term effect of cattle slurry N application on dry matter yield of reed canarygrass(Phalaris arundinacea L.) in uncultivated rice paddy during the harvested years in 1993~1995. Annual cattle slurry N was applied at the levels of 0, 90, 180, 270 and 360 kg $ha^{-1}$ in 3 cuttings, 0, 120, 240, 360 and 480 kg $ha^{-1}$ in 4 cuttings, and 0, 150, 300, 450 and 600 kg $ha^{-1}$ in 5 cutting, respectively. The results were summarized as follows; 1. The dry matter yields of all cutting frequencies in 1993 were higher than in other harvested years. 2. Significantly higher dry matter yields were obtained as 13.10 tons $ha^{-1}$ at level of 360 kg $ha^{-1}\;yr^{-1}$ in 3 cuttings, 12.50-12.83 tons $ha^{-1}$ at levels of 360-480kg $ha^{-1}\;yr^{-1}$ in 4 cuttings, and 12.52-12.56 tons $ha^{-1}$at levels of 450-600 kg $ha^{-1}$ $yr^{-1}$in 5 cuttings, respectively. 3. Efficiency of dry matter production(kg DM $kg^{-1}$ N) to cattle slurry N application tended to decrease with higher levels of cattle slurry N application and cutting frequencies. Higher efficiencies of dry matter production to cattle slurry N application were obtained as 15.2 kg at N level of 90 kg $ha^{-1}\;yr^{-1}$in 3 cuttings, 19.8 kg at level of 120 kg $ha^{-1}\;yr^{-1}$ in 4 cuttings, and 10.0 kg at level of 150 kg $ha^{-1}\;yr^{-1}$ in 5 cuttings, respectively. 4. The highest relative yields(RY) in different cutting frequency were 38.1% for 2nd cut in 3 cuttings, 41.8% for 3rd cut in 4 cuttings, and 30.1% for 4th cut in 5 cuttings, respectively. 5. The estimated ranges of marginal dry matter yield(Ymar.) were 11.5~12.1 tons $ha^{-1}$ at the ranges of economic N level of 261.0~304.6 kg $ha^{-1}\;$yr^{-1}$ in 3 cuttings, 10.4~11.5 tons $ha^{-1}$ at the ranges of economic N level of 205~302.9 kg $ha^{-1}\;yr^{-1}$ in 4 cuttings, and 11.1~11.6 tons $ha^{-1}$ at the ranges of economic N level of 303.8~354.4 kg $ha^{-1}$ 5 cuttings, respectively. 6. Ranges of economic slurry N level(Necon.) in all cuts were 67.9~95.0 kg $ha^{-1}$ in 3 cuttings, 14.3~119.8 kg $ha^{-1}$in 4 cuttings, and 50.9-125.2 kg $ha^{-1}$ in 5 cutting, respectively. 7. The 3 cuttings per annum was a proper cutting frequency for the increase in dry matter production of reed canarygrass using uncultivated rice paddy.

• 한국벤처창업학회:학술대회논문집
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• 2008.11a
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• pp.135-168
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• 2008

The Korean semiconductor industry has made a great contribution to growth of Korean economy for the last decades by maintaining a top position in terms of Korean total annual export volume. However, the advanced semiconductor equipment and materials that are used for the production of semiconductor devices still depend on the suppliers from Europe, Japan, and America who have an influential position in the Korean semiconductor industry. The objective of this study is to empirically investigate the attributes determining the extent of autonomy in decision making for the Korean subsidiaries of multinational corporations in the semiconductor industry. This study found there were differences in the extent of autonomy in decision making in terms of the global strategies the multinational corporations pursue. This study surveyed employees at the Korean subsidiaries and joint venture companies of semiconductor multinational corporations and collected 726 survey questionnaires. Several statistical analyses including frequency analysis, reliability analysis, factor analysis, multiple regression analysis and ANOVA were performed using the collected sample data. Based on the analyses, this study found as follow: Firstly, from the factor analysis, this study found Korean subsidiaries faced three sources of uncertainties stemmed from political conditions, competent conditions, demand and supply conditions. The internal resources were characterized by the independencies of production capability, financial capability, marketing capability and human resource management capability. The operational performance was determined by total revenue, net profit and market share growth. Secondly, it was found the uncertainties from political condition and competent condition and the independencies of financial capability and marketing capability partially influenced the extent of autonomy in decision making. The independencies of production capability and human resource management capability significantly influenced the autonomy of decision making in the most areas. It was also found an increase of total revenue, net profit and market share growth partially affected the extent of autonomy in decision making of the Korean subsidiaries. Finally, it was found that the polycentrism of global management by multinational corporations seemed to bring a higher extent of autonomy in decision making than ethnocentrism or geocentrism of global management. Based on the results, this study provided managerial implications regarding the extent of autonomy in decision making for Korean subsidiaries of multinational corporations in order to help management to enhance their business capabilities.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.4
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• pp.196-205
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• 2011

To investigate the contribution of macroalgae to biogeochemical nutrients and carbon cycles, we measured the uptake rates of nutrients and $CO_2$ and characteristics of fluorescence of Saccharina japonica (Laminaria japonica Areschoug) using an incubation method in an acrylic chamber. From January to May 2011, S.japonica was sampled at Ilkwang, one of well-known macroalgae culture sites around Korea and ranged 46~288 cm long and 4.8~22.0 cm wide of whole thallus. The production rate of dissolved oxygen by S. japonica (n=25) was about $6.9{\pm}5.8{\mu}mol\;g^{-1}$ fresh weight(FW) $h^{-1}$. The uptake rate of total dissolved inorganic carbon ($TCO_2$), calculated by total alkalinity and pH, was $8.9{\pm}7.9{\mu}mol\;g^{-1}\;FW\;h^{-1}$. Mean nutrients uptake were $175.6{\pm}161.1\;nmol\;N\;g^{-1}\;FW\;h^{-1}$ and $12.7{\pm}10.1\;nmol\;P\;g^{-1}\;FW\;h^{-1}$. There were logarithmic relationships between thallus length and uptake rates of nutrients and $CO_2$, which suggested that younger specimens (<100-150 cm) were much more efficient at nutrients and $CO_2$ uptake than old specimens > 150 cm. There was a positive linear correlation ($r^2$=9.4) existed between the dissolved oxygen production rate and the $TCO_2$ uptake rate, suggesting that these two factors may serve as good indicators of S. japonica photosynthesis. There was also positive linear relationship between maximal quantum yield ($F_v/F_m$) and production/uptake rates of dissolved oxygen, $TCO_2$ and phosphate, suggested that $F_v/F_m$ could be used as a good indicator of photosynthetic ability and $TCO_2$ consumption of macroalgae. Maximum relative electron transport rate ($rETR_{max}$) of S. japonica increased as thallus grew and was high in distal part of thallus which may be resulted from the increase of photosynthetic cell density per area. The annual $TCO_2$ uptake by S. japonica in Gijang area was estimated about $1.0\sim1.7{\times}10^3C$ ton, which was about 0.02-0.03% of carbon dioxide emission in Busan City. Thus, more research should be focused on macroalgae-based biogeochemical cycles to evaluate the roles and contributions of macroalgae to the global carbon cycle.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.2
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• pp.109-116
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• 2012

This study was carried out to determine the forage quality, production, and regrowth of Phragmites communis as a native grass according to growth stages. Experiment 1 was conducted in Ansan from May 2009 to April 2010 (7 stages), and experiment 2 was conducted in Cheonan from May to November 2011 (10 stages). In experiment 1, forage quality decreased rapidly with advance of growth from May. When harvested on late May, July, September and April of the following year, the contents of crude protein were 7.7%, 4.6%, 3.7%, and 2.2%, respectively. Relative feed value (RFV) were 80.2, 65.1, 61.8 and 52.8, and lignin contents were 7.1%, 9.9%, 12.0%, and 13.2%, respectively. In experiment 2, significantly higher forage yields were observed when harvested from late June to mid July. On the other hand, forage quality decreased with delayed harvest as was in experiment 1. Good regrowth of Phragmites communis was observed when harvested earlier than in August. When harvested on late May, June, July, August, September, October and November, the dry matter (DM) yields were 7,329 kg/ha, 12,527 kg, 9,593 kg, 8,279 kg, 7,649 kg, 5,822 kg and 5,540 kg, and in vitro digestible DM (IVDDM) yields were 3,924 kg/ha, 5,264 kg, 4,273 kg, 3,322 kg, 3,352 kg, 2,195 kg and 1,887 kg, respectively. Forage quality grades of Phragmites communis were 4th grade in May, 5th grade from June to Sept., and 6th grade in Oct., Nov., or in Apr. of the following year. However, all regrown Phragmites communis ranked the 4th in quality. In conclusion, we recommend that Phragmites communis should be harvested from late June to mid July (no later than the end of July) to obtain good forage quality with digestible nutrient contents greater than rice straw. Regrowth of Phragmites communis was poor, and more than 70% of annual forage yields were out of the first harvest. Therefore, we recommend only one harvesting per year for good regrowth and stable production of Phragmites communis.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.4
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• pp.207-215
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• 2019

This study was conducted to establish spring sowing techniques in preparation for the impacts of climate change on sowing time and wintering rates of winter forage crops such as barley, oat and IRG. Oat showed the highest yield in 2017 which had relatively dry climate condition. And when sowing in late Febrnary 2017 yielding 9,408kg/ha were obtained, yielding 4,011kg/ha more than IRG's sown in the same period. In 2018 which had relatively wet climate condition, four barley species decreased in the production from the previous year. Oat also had decreased by 70% from 9,408kg/ha to 2,851kg/ha. On the other hand, IRG maintained the production in the mid-5,000kg/ha range. It was also found that IRG had the least variability due to external influences regardless of seeding period for 2 years. Mixed sowing with IRG and oat in 50:50 ratio was the highest dry matter, 6,584kg/ha, and IRG was 18.5% and Oat was 2.3 times higher than single planting.

• Magazine of the Korean Society of Agricultural Engineers
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• v.22 no.4
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• pp.82-95
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• 1980

This paper complies the results of the studies so far made on the subsoil improvement of subsurface drainage systems for wet paddy fields (those were located in the Gum-Ho area in Kyung Buk province) which had poor permeability and a high water table. In general, a drainage problem is an excess of water on the ground surface which can effect the productivity and bearing capacity of the soil. With drain pipe systems, (According to their depths and spacing) it may be possible to correct that problem. The experimentation consisted of three test plots, two of which included drain pipe systems with varing depths and width spacing of the pipes. The third plot (C) was an ordinary plot being exempt of a drain pipe system. In detail, the depth of plot A was 80 cm, and the width spacings began at 2. Om and increased by 2. Om up to 10. 0m. The depth of plot B was 60cm and the width spacing was the same as plot A. These tests were performed to research specific details; such as crop yeild, bearing capacity of the soil, the amount of underdrainage, surface cracks, root distribution, the water table level, the consumptive water depth and the soil moisture content. The test period lasted three years, from 1977 thru 1979. The results obtained were as follows: 1. During the test period, the weather conditions for the area tested were in accordance with the annual average for that area. Furthermore the precipitation factor during the spring cultivation season, the intermediate drainage period and the harvest drainage period was of optimum conditions for controling surface cracks, because of less precipitation than evaporation. 2. The difference in the level of the ground water table in plots A and B was hardly noticable, but the difference in the test plots and the ord. plot was greatly noticable. The test plots (A, B) were 30 to 40cm lower than the ordinary plot. On the whole, the ground water table of the ord. plot always stayed at a level of 15-20cm beneath the surface of the soil, the ground water table of the test plot A showed The difference in the depth of the pipe lower than the test plot B, while the test plots showed a remarkable descending effect. 3. The soil temperature in plot A was slightly core than in plot B with a difference of 0. 47$^{\circ}$C, but plot A was 1. 6$^{\circ}$C higher than the ord. plot during the flooding period, but after drainage the temperature difference climed to 2. 0$^{\circ}$C. 4. During the 3rd test year, the values of the cracks were recorded with the values of 59cm in plot A, 42cm in plot B and 15cm in the ordinary plot. Plots A and B had increased 2.5 times the value of the first year while the ordinary plot had remained the same. 5. The root weight of the rice was measured at a value of 77.2 gr. for plot A, 73.5 gr. for plot B and 65.3 gr. for the ord. plot. Therefore, the root growths in plots A and B were much more energetic than in the ord. plot. 6. The consumptive water depth measured during the 3rd year resulted in the values of 26. 0mm per day for plot A, and 24.9 mm per day for plot B, respectively. Therefore, both plot A and plot B maintained the optimum consumptive water depths, but the ordinary plot only obtained the value of 12.3 mm per day, which clearly showed less than the optimum consumptive water depth which is 20 to 30 mm/day. 7. The soil moisture content is in direct relationship to the ground water level. During drainage, test plot A decreased in its ground water level much more rapidly than the other two plots. Therefore, plot A had a much less soil moisture content. But this decreased water level could be directly effected by the weather conditions. 8. The relationship between the bearing capacity and the soil moisture content were directly inversely proportional. It can be assumed that the occurence of soil creaks is limited by the soil moisture content. Therefore, the greater the progress of the surface creaks resulted in a greater bearing capacity. So, tast plot A with a greater amount of surface cracks than the other test plots resulted in a greater bearing capacity. But, the bearing capacity at the harvest season could be effected by the drainage during the intermediate drainage period and by the weather conditions. 9. Comparing the production of the test plots to the ord. plot; there was an increased value of 840kg for plot A, 755kg for plot B and 695kg for the ord. plot in the rough rice. Therefore, plot A had an increase of 20% over the ordinary plot. The possibility of producing double crops was investigated. The effects on barley production in the test plots showed a value of 367kg per 10 acres, which substantiated the possibility of double crops because that value showed an increased value over the average yearly yield for those uplands. 10. So as a result, it can be recommended that by including a drain pipe system with the optimum conditions of an (80cm centimeter) depth and a (l0m) spacing will have a definite positive effect on the over all production capacity and quality of wetpaddy fields.

• Journal of Ecology and Environment
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• v.29 no.6
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• pp.585-591
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• 2006

We measured the litterfall quantity and investigated the nutrient dynamics in decomposing litter for three years at the LTER sites installed in a deciduous broadleaf natural forest in Mt. Gyebangsan, South Korea. Litterfall production was significantly different among the sampling dates, whereas it was not significantly different among the years. The total annual mean litterfall production for three years was 6,593 kg $ha^{-1}$ $yr^{-1}$ and leaf litter accounted for 82.6% of the litterfall. The leaf litter quantity was highest in Quercus mongolia, followed by leaf of other species, Betula schmidtii, Kaplopanax pictus, Acer pseudo-sieboldianum, etc., which are dominant tree species in the site. The mass loss from the decomposition of leaf litter was fastest in Cortinus controversa (100%), followed by A. preudo-sieboldianum, K. pictus, and B. schmidtii. 100% of litter for C. controversa, 96.1% for A. pseudo-sieboldianum, 92.8% for K. pictus decomposed, while 66.2% of litter for Q. mongolia decayed for 1,003 days. The lower rate of the mass loss in the litter of Q. mongolia may be attributed to the difference in substrate quality, such as lower nutrient concentrations compared with those of other tree species. The concentrations of N, P, and Ca for five litter types increased over time, while the concentrations of K and Mg decreased over time. Compared with the nutrients in the litter of Q. mongolia, the nutrients (N, P, K, Ca, Mg) in the litter of other species, C. controversa, A. pseudo-sieboldianum, and K. pictus, were released more rapidly. The results showed that the mass loss and the nutrient dynamics in the litter are variable depending on the tree species even in the same site conditions.

• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.4
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• pp.3170-3180
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• 1973

This study of the subject will review past and present irrigation development in Korea. Particular attention will be given to water pricing structure and a case study on the purpose of rational operation and management of irrigation water and organizations, and the optimum irrigation water and organizations, and the optimum irrigation water fee inorder to reduce farmers burden and to rationalize the farmland associations management so as to achieve development of the rural environment. In 1971, the reservoir of the Farmland Improvement A sociation (FIA) produced only 775 millison $m^3$ of irrigation water or 77% of planned capacity of 1,015 million $m^3$. It was caused by inefficient maintenance of irrigation facilities; for instance, about 21% of reservoirs, pumping stations and weirs in Korea have been silted by soil erosion which hinder to water production according to an ADC survey. The first Irritation Association was established in 1906, whcih was renamed the Farmland Assoeiation by the Rural Development Enouragement Law in 1970. By the end of 1971, 411,000 ha of rice paddies were under the control of 267 associations nationwide. The average water price assessed by Associations nationwide rose from 790 won per 0.1 ha. in 1966 to 1,886 won in 1971. The annual growth rate was 20%. The highest water price in 1971 was 4,773 won her 0.1 ha. and the lowest was 437 won. This range was caused by differences in debt burden, geographic conditions and management efficiency among the Associations. In 1971, the number of Associations which exceeded the average water price of 1,886 won per 0.1 ha. was 144, or 55.1% of all Association. In determination of water price, there are two principles; one is determined by production cost such as installation cost of irrigation facilities, maintenance cost, management cost and depreciation ect. For instance, the Yong San River Development project was required 33.7 billion won for total construction and maintenance cost is 3.1 billion won for repayment, maintenance and management cost per year. The project produces 590 million $m^3$ of irrigation water annually. Accordingly, the water price per $m^3$ is 5.25 won. The other principle is determined by water value in the crop products and in compared with production of irrigated paddy and non-irrigated paddy. By using this method, water value in compared with paddy rice vs. upland rice(Average of 1967-1971) was 14.15 won per $m^3$ and irrigated paddy vs. non-irrigated paddy was 2.98 won per $m^3$. In contrast the irrigation fee in average association of 1967-1971 was 1.54 won per $m^3$. Accordingly, the current national average irrigation fee(water price) is resonable compared with its water value. In this study, it is found that the ceiling of water price in terms of water value is 2.98 won per $m^3$ or 2,530 won per 0.1 ha. However, in 1971 55% of the associations were above the average of nationwide irrigation fees. which shows the need for rationalization of the Association's management. In connection with rationalization of the Association's management, this study recommends the following matters. (1) Irrigation fee must be assessed according to the amount of water consumption taking intoaccount the farmer's ability. (2) Irrigation fee should be graded according to behefits and crop patterns. (3) Training personnel in the operation and procedures of water management to save O&M costs. (4) Insolvent farmland association should be integrated into larger, sound associations in the same GUN in order to reduce farmers' water cost. (5) The maintenance and repair of existing irrigation facilities is as important as expansion of facilities. (6) Establishment of a new Union of Farmland Association is required to promoted proper maintenance and to protect the huge investment in irrigation facilities by means of technical supervision and guidance.

• Korean Journal of Environment and Ecology
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• v.36 no.2
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• pp.177-201
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• 2022

Following the adoption of the global plant conservation strategies at the Conference of the Parties for Biodiversity Conservation, diligent actions to achieve each targets are actively carried out. In particular, the need for ecological conservation research to achieve targets 2 and 7 of GSPC-2020 has increased. The priority taxa to accomplish the objectives of GSPC-2020 are rare and endemic plants. In particular, endemic plants with limited distribution in specific regions are evaluated to face a high risk of extinction. To address the necessity to preserve endemic plants, we investigated the distribution of Prunus choreiana H. T. Im, a Korean endemic plant. After that, we examined the vegetational environment of the habitat of P. choreiana and evaluated its population structure. The productivity of its fruits and the effects of pollinators on fruit production were evaluated as well. The fruiting ratio was calculated based on the number of flowers produced. Lastly, we observed the annual growth characteristics of P. choreiana. The habitats of P. choreiana did not show a specific type of vegetation. All of them were located in a limestone area of Gangwon-do in the central Korean Peninsula and occupied a site where the coverage of the tree layer and the sub-tree layer was not high or did not exist. The population structure of P. choreiana contained a high proportion of mature plants capable of producing fruits and a low proportion of seedlings and Juvenile plants. We found that the production of fruits required pollinators and was affected by the performance of each plant. Although P. choreiana produces many flowers, only a maximum of 20% and only 2-6% on average bear fruits. These flowering characteristics may be due to pollinators' low abundance and activity during the flowering season (between mid-March and early April), suggesting that many flowers are needed to attract more pollinators. We rarely observed the re-establishment of seedlings in the population of P. choreiana. Despite that, we predict the population to persist owing to its long lifespan and periodic production of numerous fruits. However, if the tree layer and sub-tree layer in competing status with P. choreiana increase their crown density, they are expected to inhibit the growth of P. choreiana and affect the risk of its extinction. Therefore, the current changes in the vegetational environment of the habitats are expected to decrease the number and extent of P. choreiana in the long term. The results of this study may serve as primary and important data necessary for the achievement of GSPC-2020 objectives.

• Korean Journal of Organic Agriculture
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• v.16 no.1
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• pp.115-125
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• 2008

This study was conducted to determine adequate forage crop choice and optimal level of livestock manure, when different types and levels of the livestock manure were applied in corns or sorghum$\times$sorghum hybrids for the production of organic roughages by utilizing livestock manure. For the corn, yields of annual dry matter (DM) and total digestible nutrients (TDN) were highest in N+P+K-applied treatments, showing 17.3 and 11.7 ton/ha, respectively. Treatments applied 100% composted cattle manure (8.9 and 6.1 ton/ha) and 100% cattle slurry (9.4 and 7.5 ton/ ha) in contrast with chemical fertilizer-N had higher yields of DM and TDN than no fertilizer (4.8 and 2.7 ton/ha) and P+K-applied treatments (8.8 and 6.0 ton/ha). Particularly, treatments applied 150% composted cattle manure and 150% cattle slurry were markedly higher, which represented 11.4 and 7.6 ton/ha and 10.3 and 7.3 ton/ha, respectively. Crude protein (CP) contents for corns applied livestock manure ranged from 5.6 to 6.6%, which were significantly (p<0.05) higher than those of no fertilizer (3.9%) and P+K-applied treatments (5.5%). ADF (42.4%) and NDF (58.3%) contents for no fertilizer treatment were significantly (p<0.05) higher than those of other treatments. However, TDN contents were higher for livestock manure treatments than for no and/or chemical fertilizer treatments. In particular, TDN contents of treatments applied 150% composted cattle manure and 150% cattle slurry showed 72.3 and 70.8%, respectively and both treatments were significantly (p<0.05) higher than all of the other treatments. For the sorghum$\times$sorghum hybrid, yields of annual DM and TDN for 100% (12.4 and 7.4 ton/ha) and 150% (13.1 and 7.6 ton/ha) cattle slurry-applied treatments, and N+P+K-applied treatments (12.6 and 7.7 ton/ha) were significantly (p<0.05) higher than those of the others. In the others, 150% composted cattle manure (9.3 and 5.2 ton/ha) had higher annual DM and TDN yields than P+K-applied (8.4 and 4.8 ton/ha) and 100% composted cattle manure treatments (7.4 and 4.2 ton/ha), with no significant difference. Crude protein contents for sorghum$\times$sorghum hybrid applied P+K and cattle slurry were 8.8 and 8.6%, respectively. CP contents for both treatments were significantly higher than those of composted manure ($7.5{\sim}8.3%$) and no fertilizer (4.0%) treatments, but 100% livestock manure treatments had higher CP contents than 150%-applied treatments. ADF and NDF contents for N+P+K and cattle slurry-applied treatments were significantly (p<0.05) lower than the others. However, TDN contents were highest in N+P+K and cattle slurry-applied treatments, showing 61.2 and 58.3 to 59.4%, respectively. These results indicated that application of livestock manure instead of chemical fertilizer to the soil of forage crops might not only improve yields of DM and TDN, but also reduce environmental pollution by producing organic roughages through recycling of livestock manure.