• Asian Journal of Turfgrass Science
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• v.9 no.1
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• pp.11-42
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• 1995

The investigation was made on the relationship among vegetation, net productivity, regrowth and soils of Moonheri-Wasoori, Soodowon-Sungilkyo and Mt. Kumhak grasslands in Chulwon area. The following conclusions have been made as the results of this study. The vascular flora of the grassland in Moonheri-Wasoori was composed of 102 species, the most of which were Medicago denticulata, Miscanthus sinensis, Arundinella hirta, Festuca ovina and Cassia nomame. The flora of Soodowon-Sungilkyn grassland was composed of 74 species, the most of which were Arundinella hirta, Miscanthus sinensis, Carex nanella, Festuca ovina and Cassia nomame. It of Mt. Kumfiak grassland was composed of 78 species, the most of which were Arundinella hirta, Carex nanella, Festuca ovina, Miscanthus sinensis and Aster scaber. These five species contributed greatly to the standing crop of live material which was in excess of 60% of it. The peak standing crop of each 413.7, 307.6 and $348.7g /m^2$ in Moonheri-Wasoori, Soo- dowon-Sungilkyn and Mt. Kuruhak grasslands wars reached in August under flooded conditions as a result of the growth of dominant species, Medicago denticulata and Arundinella hirta. The net prodution of organic matter was slight in some intervals but occurred throughout the growing season After cutting of grasses, the regrowth of new leaves mainly depended on growing stage and edaphic factors. Characteristics of the natural grassland soils, especially, concerning water, total nitrogen, avail-able phosphorus and exchangeable calcium were clarified and might be depend upon the quantity of plant production. Nitrogen, phosphorus and calcium concentration of leaves of Medicago denticulata, Arundinella hirta and Miscanthus sinensis were higher than of stems. Even if diem we diffurmem in the a-mb of nutrients among Medicago denticulata hirta and Miacanthus sinensis for single species and stands. they were covered by variations within species in the present survey. Key words: Competition, Production, Productivity, Regrowth, Soil Properties, Vascular Flora.

• Korean Journal of Medicinal Crop Science
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• v.3 no.3
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• pp.226-232
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• 1995

Extraction methods and instrumental analytical conditions were compared to establish a fast and appropriate analytical method to determine saikosaponins in Bupleurum falcatum. Using HPLC, analysis of diene-saikosaponin treated with 2% acid was faster than that of saikosaponin itself. Among various extraction methods, extraction by standing in methanol at room temperature showed highest efficieny, and extraction with boiling methanol was shorter in analytical time and showed good chromatogram. And we could analyze many samples faster using HPTLC but the analytical accuracy was low. In extraction and analysis of saikosaponins, extraction with boiling methanol and acidic treatment was fast and easy analytical method. And for selecting useful lines in component breeding, we think TLC method was better.

• Korean Journal of Environmental Biology
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• v.17 no.1
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• pp.117-124
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• 1999

Nutrients removal by water hyacinth, Eichhornia crassipes (Mart.) Solms from nutrient enriched waters and swinery wastewater were evaluated. The contents of nitrogen and phosphorus of dried water hyacinth increased from 1.4 to 3.3% and 0.21 to 0.80% when water hyacinth available N and P in the culture medium were increased from 0.7 to 5.0 mgN/1 and 0.06 o 1.5 mgP/l. respectively. Maximum N and P contents were found to be 4.1 and 0.90%, respectively. The significant relationship was observed between the standing crop of water hyacinth and the biomass yield per unit area and time. Biomass yield increased gradually until standing crop reached 15 kg wet wt./m$^2$, and then rapidly decreased. The high biomass yield of up to 0.5 kg/m$^2$/day was obtained in the range of 7 to 20 kg/m$^2$of standing crop. The potential removal rates of N and P by the water hyacinth during summer were found to be 2,250 to 2,710 mgN/m$^2$/day and 570 to 595 mgP/m$^2$/day, respectively, when 15 kg/m$^2$in standing crop and nutrient concentrations of culture medium were ranged from 1.24 to 6.2 mgP/1 and 3.2 to 32.5 mgN/1, respectively, Inorganic N and P concentrations of swinery wastewater were in the range of 82 to 121 mgN/1 and 22 to 79 mgP/1, respectively. Nitrogen and P removal rates of water hyacinth cultured in swinery wastewater were found to be in the ranges of 2,000 to 2,600 mgN/m$^2$/day and 157 to 254 mgP/m$^2$/day, respectively, at 10 times diluted water of swinery wastewater.

• Journal of Korean Society of Forest Science
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• v.12 no.1
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• pp.45-54
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• 1971

Ecological studies on the effect of an accidental fire on the composition of the post-fire vegetation in relation to the productivity system were made at the burned site on Mt. Samak located at Duckduwon-Ri, Sumyun, Chun Sung-Kun, Kangwon-Do, the same plots used in the previous study carried out in 1967. The result are summarized as follows. 1. In the productivity system, the standing crop measured was as follows; Carex Lanceolata var. Nana, Miscanthus purpurscens etc. were contained in the herbs and their individual number was larger than that of the woody plants. (Table 1). In the woody plants, Quercus Acutissima was the most abundant, showing larger number of tree than Quercus dentata. The S.D.R. value of the family Poaceae was the highest among the herbs and in the test plots, it was 4 times larger in number than in the controlled plots. (Table 3, Fig. 4, 5). 2. In the unburned sities, 5 dominant species were selected and by calculating their S.D.R., it was shown that woody plants, S.D.R. is 4.43 while it is 11.52 with herbs. (Table 4, Fig. 6). 3. When making comparisons with the standing crop on the higher around, it was found that the test plots had 522.45 gm more than the controlled and 1470. 53gm more than those on lower ground. These results were considered to indicate that high temperature caused by fire resulted in the increase of germination rate of seeds as it was seen in the previous study and it further stimulate the growth of the perennial plants. (Table 6, 7) 4. In the number of species, the standing crop was increased in the order of Genus Miscanthus and Genus Carex. and in the woody plants Genus Lespedeza was increased in the standing crop. 5. It was found that in the rest plots, total summed height was greater by about 6000cm than that in the controlled plots. 6. In conclusion, the forest fire gave a great loss to tall trees and woody plants burning them together with unmatured seeds. In the succession of the 2nd year it was considered that the growth of the perennial plants had been stimulated on the barned sites.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.90-90
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• 2022

Nicaragua is located in Central America, climatic conditions are considered tropical dry forest. Statistics reflex that in Nicaragua exits 24,000 rice farmers. National rice production only covers 73% of the national consumption. It exists two sowing system: irrigation and rainfed. Varieties used in both systems are mid-late maturity (120-135 days), there are 14 released varieties for irrigation, eight for rainfed, and eight landraces used in rainfed. The current breeding system (introduction of lines from Colombia) has increased the national production, however, has some limitation due to the lack of enough variability, reducing the proability of finding good genotypes and therefore the possibility of satisfying 100% of the demand. The purpose of this study was to analyze the problems that must be resolved in the short and long term to improve rice productivity in Nicaragua. In this paper we explain some proposal for an improvement plan. The selection of varieties with high adaptability to various cultivation environmental conditions it is necessary, also to thoroughly manage seed purity to supply certified seeds. In rice cultivation technology, it needs to improve seedling standing and weeding effect by improving soil leveling and water-saving cultivation technology. Also, proper fertilization and planting density must be established in irrigated and rain-fed areas. Furthermore, capacity must be strengthened by collecting and training with the most recent agricultural technology information, as well as by revitalizing the union rather than the individual farmer. It is necessary to develop varieties highly adaptable to the Nicaraguan cultivation environment, as well as to expand irrigation facilities and cultivation technology suitable for weather conditions in rain-fed areas. Last, it is necessary to maintain the consistency of agricultural policy for continuous and stable rice production in response to climate change events such as drought or intermittent heavy rain.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.20
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• pp.74-86
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• 1975

Experiments were carried out to know some physiological characters of several rice varieties such as Suweon 213-1, Suweon 214, Palkweng, Akibare and Nongbaek. In experiments, total standing crop, leaf area and total net production of dry matter were higher in the variety of Suweon 213-1 than the other varieties. RGR, NAR and CGR showed the highest at heading period of Suweon 213-1 than the other varieties. Efficiency of solar energy utilization also showed the highest through the entire growing period of Suweon 213-1. The amount of net production and dead parts could be estimated by the successive application of the productive structure.

• Journal of Plant Biology
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• v.18 no.3
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• pp.129-134
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• 1975

It was studied of relation between biomass of reed communities (Phragmitis communis) and several environmental factors concerned with such as chlor ine, pH, humus content in soil and depth of seawater submerged. Two sites where were the different geographical conditions were set up. One site had two plots: H plot, at theshallows of seawater, was not submerged except at full tide or at heavy rainfall, and M plot, at medium depth of seawater, submerged at every common tide at inside of a bank along the west seashore of Mu-An-peninsula. The other site also two plots: M' plot, at medium depth, submerged about 10 hours at each tide, and L plot, at deep seawater submerged every tims at tide at the outside of a bank along the eastside estuary of Youngsan river. Maximum standing crop of the reed community was shown on 25th of June: biomass at H M, M' and L plot were respectively 4.65, 3.60, 0.98, and 0.67 kg dry weight per $m^2$. Density of individual at H, M, M' and L plot was 67, 78, 244 and 333 plants per $m^2$. Net production of the terrestrial parts of rred community on the outside of the bank were lesser as much as a sixth than that on inside, but the density of the plant on outside of the bank was higher as much 4 or 5 times than that on inside. It was assumed that the growth of reed plant was inhibited by high chlorine, high pH, less humus in soil and submergence of seawater for long period.

• Korean Journal of Environmental Biology
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• v.30 no.3
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• pp.193-199
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• 2012

We performed qualitative and quantitative surveys on the distribution of seaweed species and dominant species with their standing crop and temporal variations in Hauido tidal flats in order to understand the role of seaweeds in a coastal wetland ecological system that may be used for conservation and management of coastal wetland ecological system. A total of 9 species were found at 7 stations of the study area; 4 species of Chlorophyta (Ulva compressa, U. prolifera, U. pertusa and Ulothrix flacca), 3 species of Phaeophyta (Ectocarpus arctus, Scytosiphon lomentaria and Myelophycus simplex) and 2 species of Rhodophyta (Gracilaria verrucosa and Caulacanthus okamurae). Major dominant species were U. compressa, U. prolifera and U. pertusa (Chlorophyta), Scytosiphon lomentaria (Phaeophyta) and Gracilaria verrucosa (Rhodophyta). Standing crops of U. compressa and U. prolifera were $2.94{\sim}45.25g{\cdot}dw{\cdot}m^{-2}$ and $6.19{\sim}91.9g{\cdot}dw{\cdot}m^{-2}$, respectively, in spring. Seaweed habitat was characterized by textural differences that the percentage of coarse particles and organic material were a little higher in seaweed flourishing areas than in seaweed barren areas.

• Journal of Environmental Science International
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• v.21 no.3
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• pp.313-326
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• 2012

Three embankments, namely Changpo, Bokkil and Guil, in Chunggye Bay were investigated to assess the influence of environmental changes to phytoplankton size structure, distribution of species and standing crops. Three stations was sampled near at each embankment in Nov. 2006, Feb. 2007, May 2007 and Aug. Phytoplankton were classified into net-size (>20${\mu}m$) and nano-size (<20${\mu}m$). In summer, the freshwater discharge seemed to have influence in the decrease of salinity and in the increase of turbidity, ammonium and phosphorus concentrations. Chl a concentration and phytoplankton abundance in Feb. 2007 were observed to be generally higher in all stations compared to other periods. Net-size phytoplankton was observed to be higher in Feb. 2007 and May 2007 compared to nano-sized phytoplankton. However, there was shift in phytoplankton composition in Nov. 2006 and Aug. 2007. Phytoplankton under seven class (Bacillariophyceae, Chlorophyceae, Chrysophyceae, Cryptophyceae, Cyanophyceae, Dinophyceae, Euglenophyceae) was identified during the study period. It was found out that the major phytoplankton class was Bacillariophyceae. Phytoplankton was more diverse in autumn compared to any other season. Cyanophyceae was increased in summer. In rainy season, change in physical factors (salinity, transparency) seemed to have more influence on phytoplankton growth compared to inorganic nutrients.

• Korean Journal of Medicinal Crop Science
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• v.2 no.2
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• pp.105-109
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• 1994

This experiment was conducted to know the labor saving effect and reducing production cost by agricultural mechanization in the cultivation of Bupleurum falcatum. Labor reducing effects of the drilling seeder by hand and the machine attached to two wheel tiller were 97%, but emergency rate was highest in the former. Dry root yield per plant was increased by low amount of seed sowing but that yield per unit area was increased at much seeding amount in the seeder attached to the tiller. The drilling seeder by hand was showed highest standing ratio of seedling and produced yield to 84.1kg of root yield per 10a. Labor saving effect was the best at the multipurposes mechanized harvester and labor saving and famer's income ratio were increased to 69% and 50% respectively. Labor time and cost were reduced to 74% and 69% respectively by mechanization of sowing and harvest cultivation practice on Bupleurum falcatum.