• Korean Journal of Weed Science
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• v.4 no.1
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• pp.39-51
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• 1984

Effects of major phenolic acids identified from barley residues (straw, root) on the germination of rice and 3 paddy weeds such as Echinochloa crusgalli, Cyperus serotinus, and Potamogeton distintus were evaluated to obtain the basic informations on the development of naturally occurring herbicides. The predominant phenolic compounds extracted from barley residues in both straw and root were identified as p-coumaric, p-hydroxybenzoic, ferulic, vanillic, and salicylic acids by means of paper chromatography. Total phenol content of barley straw and root at the harvesting stage was 0.169% and 0.127% per dry weight, respectively. During the decomposing process, total phenol content slightly increased and then decreased. The germination of test plants was inhibited by treatments of 4 major authentic phenolic acids identified, most significantly on rice, and less on E. crusgalli, and C. serotinus. P. distintus, however, was markedly stimulated by them as the concentration increased, and then sprouted buds of pondweeds were changed to dark brownish color, resulting in the death as the treatment prolonged. The greater inhibitory effect appeared on shoot growth rather than germination. The aqueous extracts of barley residues showed the similar inhibitory effect on the germination and shoot growth of rice and three paddy weeds as the treatments of 4 authentic phenolic acids.

• Korean Journal of Weed Science
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• v.17 no.3
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• pp.269-280
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• 1997

Collated data from the 1995-1996 field surveys of weed seeds buried in the plough layer of peat soil in Selangor district were analysed to assess species-dominance and spatial pattern of distribution of weed seeds based on selected quantitative indices and index of dispersion. Forty five species within 14 families were recorded of which 24 were broadleaves, 12 grasses and 9 sedges. They comprised ca. 53.2, 31.2 and 15.6%, respectively based on total population counts. Total seed population was ca. $8.14{\times}10^7$ seeds/ha within the fast 25cm soil depth. Wide variabilities in population counts were registered among species ranging from < $7.0{\times}10^4$ seeds/ha for Amaranthus gracilis to ca. $5.64{\times}10^6$ seeds/ha for Heteropogon contortus. Seeds of Cleome rutidesperma was the most abundant(ca. $2.347{\times}10^7$ seeds/ha). Difference in seed population counts may be attributed to inherent variation in fecundity, population fluxes, their spatial distribution patterns and the agronomic practices prevailing in the areas of survey. The profile distribution of soil seed banks was skewed within the first 0 - 10cm depth, comprising ca. 69% of the total seed counts. Seed counts in the 10 - 15, 15 - 20 and 20 - 25cm soil profiles were in the order of 17.9, 8.6 and 4.0% of the total populations, respectively. Weed seeds of all species displayed different degree of aggregated pattern of distribution with variance-to-mean ratios of > 1 and Lloyd's mean crowding($m^*$) values from 1.244 for Cyperus iria, Phyllanthus debilis, Phyllanthus urinaria, Scirpus grosses and urinaria lagopodiodes to 9607.7 for Cleome rutidosperma. Lloyd's patch indices(Ip) ranging from 5.1 for Aeschynomene indica to 188.5 for Bracharia reptans were registered. Differences in the VMR, $m^*$ and Ip values among species suggested inter-alia inherent variabilities in their disposal capacity from seed source and different agronomic practices prevailing in the areas surveyed.

• Korean Journal of Weed Science
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• v.11 no.3
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• pp.178-186
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• 1991

This study was conducted to evaluate the major weeds occurred in direct seeded rice and their compition with rice, and to establish the effective weed control method. The important weeds occurring in dry direct seeded rice were Echinochloa crusgalli, Cyperus amuricus, Rorippa islandica, etc. Among them, Echinochloa crusgalli was the most dominant weed species. In view of the Simpson's dominance index, the maximum number of the weeds was observed at 30 days after seeding, showing 0.26, but decreased as the time passed. In other hand, Simpson's dominance index of weed dry weight increased from 0.09 at 15DAS(days after seeding) to 0.28 at 60DAS indicating that particular weed such as barnyardgrass was dominating the fields. The plant height and the tiller number of rice in the dry direct seeded rice were not greatly affected by the time and duration of competition with weeds, but rice yield was greatly influenced by them. The yield reduction was observed when compition between rice and weeds were initiated at 20 to 40 DAS till the harvesting time. The highest weed control efficacy was observed at the treatment of systematic herbicide application such as soil applied Butachlor followed by Mefenacet/Bensulfuron-methyl/Dymron at 30 DAS after seeding, and soil applied Dimepiperate/Bensulfuron-methyl mixture as a preemergence type gave also an excellent control.

• Korean Journal of Weed Science
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• v.6 no.1
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• pp.25-32
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• 1986

This experiment was conducted to evaluate effect of various hormones on callus induction, and on plantlet formation on various media, and to detect of Londax [Methyl 2-[[[[[(4,6-dimethoxy pyrimidin-2-yl) amino] carbonyl] amono] sulfonyl) methyl] benzoate] and Basta[Ammonium-(3-amino-3-carboxy-propyl)-methyl phosphinate] on callus growth and reaction of succinate dehydrogenase in callus against TTC, using various species such as Eleocharis kuroguwai, Cyperus serotinus, Oryza sativa (samgangbyeo) and Echinochloa crusgalli P. Beauv. var. caudata Kitagawa. The optimal levels of 2,4-D in MS medium seems to be different among species tested, 2.0 ppm for rice and E. crusgalli, 1.0 ppm for Eleocharis kuroguwai, and 4.0 ppm for C. serotinus derived callus from shoot-tip. In case of combination of 2,4-D with BA, 1.0 plus 0.3 ppm appeared the most appropriate level to induce callus from rice and E. kuroguwai, and I.0 plus 0.1 ppm for C. serotinus and E. crusgalli. When 2,4-D treated with TIBA, 1.0 plus 0.5 ppm appeared the most appropriate rates to induce callus derived from seeds of rice, E. crusgalli, seeds of C. serotinus and E. kuroguwai, 1.0 plus 0.3 ppm for shoot-tip of C. serotinus. Positive reaction of succinate dehydrogenase against TTC was observed regardless of calli and herbicides tested, indicating that they all are alive, and these herbicides were not able to kill the calli tested within the short period of time 20 hrs treatment. Regardless of plant species used, the rate of plantlet formation from callus was very low. However, some plantlet formed from E. crusgalli at 0.8 ppm of 2,4-D plus 8.0 ppm of kinetin, and from E. kuroguwai at 1.6 ppm of 2,4-D plus 16.0 ppm of kinetin, showing effectiveness of 2,4-D with kinetin mixture treatment. No callus was induced from C. serotinus treated with Basta from $10^{-6}M$ to $10^{-3}M$. In general, rice was the least susceptible to Basta among plant species tested, followed by E. crusgalli, and E. kuroguwai. In Londax treatment, rice showed the least inhibition rate in callus growth. Callus was induced from rice even at $10^{-3}M$ of Londax. However, $10^{-3}M$ of Londax completely inhibited callus induction from the test species. Rice showed most tolerant to both herbicides, indicating the existence of different responses among plant species.

• Korean Journal of Weed Science
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• v.14 no.4
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• pp.245-251
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• 1994

The initial growth and herbicidal responses of Scirpus planiculmis were examined under both laboratory and greenhouse condition. Initial growth of S. planiculmis at two different soils(soil A and B), was compared with the growth at normal paddy soil, and growth rates at two soils were 32% and 86% as compared to the growth rates at normal paddy soil. Two different soils were soil A(rice-uncultivable) and soil B(rice-cultivable). Transplanted(2.5 leaf stage) and direct seeded rice(Dongjinbyeo) could not grow at soil A. The growth of transplanted rice at soil B was almost same as the growth at normal paddy soil, but the growth of direct seeded rice was 50% of the growth at normal paddy soil. S. planiculmis among the perennial weeds was most tolerant to NaCl, and Cyperus serotinus, Eleocharis kuroguwai, Sagittaria pygmaea, Sagittaria trifolia, Potamogeton distinctus were followed. The intial growth rate of S. planiculmis was more rapid than C. serotinus. Cutting types and times of corm reduced 20-40% of the initial growth of S. planiculmis. During the initial growth of S. planiculmis, the growth of S. planiculmis was severly inhibited by the earlier removal of corm from seedlings, and it represents that the corm plays an important role in the initial growth of this species. Bentazone among 14 commercialized herbicides showed the best safety on direct seeded rice and the highest control effect agaist S. planiculmis.

• Journal of Sericultural and Entomological Science
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• v.23 no.2
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• pp.11-36
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• 1982

Forty-nine plant species as additives to silkworm artificial diet and 5 species as cellulose sources for artificial diet were screened for their economic values as feed-resources for the silkworm. Feeding response to artificial diet was tested on 82 silkworm strains. The effect of rearing conditions on feeding response and enzyme activities in the silkworm was investigated. The results were summarized as follows. 1. Seven species out of 49, Vigna sinensis ENDL, Ipomoea vatatas Lamarck, Cyperus anuricus Var. Laxus, Alnus japonica Stendel, Trifolium repens L, Prunus serrulata Lindley. Var, Glycine max L increased feeding response, compared with the basic formula of artificial diet. 2. The economic values of Vigna sinensis ENDL, Ipomoea vatatas Lamarck, Cyperus anuricus Var. Laxus, Ainus japonica Stendel, Cassia tera L, Erigeron canedensis L as feed-resources for artificiale diet were recognized, through feeding experiment during the entire larval stage. 3. Mulberry cellulose showed the best results in rearing and cocoon characteristics. 4. The extent of feeding response varied according to strains and varieties. Varieties in japanese strains showed higher feeding response than those in chinese and european varieties, with considerable variations among a varieties in strains. 5. The begining of 4th instar seems to be a proper time to convert from mulberry to artificial diet, or artificial diet to mulberry, however the middle of 3rd instar seems acceptable. 6. The optimum temperature for artificial diet rearing is 30$^{\circ}C$ during the period of 1st-3rd instar and 28$^{\circ}C$ for 4th-5th instar. 7. Electrophoretic isozyme patterns of esterase and acid phosphatase on agarose gel, as affected by strain. rearing temperature and feed-resources, were observed as follow. (1) Isozyme patterns of mid-gut esterase varied, depending on instar. One or two more isozyme bands were observed in the larvae than feed on the mulberry fed for the artificial diet. (2) A strain, chinese-15 with a higher feeding response, had 1∼2 more bands than chinese-60 with a lower feeding response. (3) Five bands of mid-gut esterase in 3rd and 4th instar larvae reared at 28$^{\circ}C$. and 4 for 3rd instar and 6∼7 for 4th instar larvae at 35$^{\circ}C$ were observed. (4) No similar esterase bands could be found among mid-gut, blood and silkgland. There are five esterase bands in the midgut, one in blood and three in silkgland. (5) There was rather small digerence in acid phosphatase types of mid-gut and blood according to varieties and rearing temperature. No active band was shown in silkgland. In midgut, there was one acid phosphatase band at 3rd instar, two at 4th instar and three at 5th instar. In blood, one active band at 3rd or 4th instar and three bands at 5th inster wire detected.

• Journal of Wetlands Research
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• v.7 no.3
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• pp.87-95
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• 2005

Vegetation structure of the vascular plants was investigated from March 2003 to October 2003 in Haepyeong wetland, Gumi-si, Gyeongsangbuk-do, Korea. Actual vegetation of Haepyeong wetland largely can be classified by floristic composition and physiognomy into 18 communities; Xanthium strumarium-Digitaria sanguinalis, Humulus japonicus, Persicaria perfoliata-Humulus japonicus, Phragmites japonica-Miscanthus sacchariflorus, Persicaria hydropiper-Phragmites communis, Persicaria hydropiper, Phragmites japonica-Persicaria hydropiper, Miscanthus sacchariflorus- Phragmites japonica, Persicaria hydropiper-Phragmites japonica, Miscanthus sacchariflorus-Salix glandulosa, Salix nipponica-Salix glandulosa, Salix nipponica-Salix koreensis, Salix nipponica, Miscanthus sacchariflorus-Salix nipponica, Phalaris arundinacea-Salix nipponica, Salix glandulosa-Salix nipponica, Trapa japonica, and Ceratophyllum demersum-Trapa japonica. Among them, the area of the Salix nipponica-Salix koreensis community was the largest as 122.2ha(9.23%). The dominant vegetation type was Miscanthus sacchariflorus-Persicaria hydropiper community based on phytosociological method, and it was was classified into three subcommunities; Salix glandulosa-Salix nipponica subcommunity, Digitaria sanguinalis subcommunity, and Cyperus amuricus subcommunity. Differential species of Salix glandulosa-Salix nipponica subcommunity were Salix nipponica, S. glandulosa, S. koreensis, Scirpus radicans, Persicaria maackiana, and Achyranthes japonica; differential species of Digitaria sanguinalis subcommunity were D. sanguinalis, Setaria viridis, Ambrosia artemisiifolia var. elatior, and Cyperus orthostachyus; differential species of Xanthium strumarium subcommunity were X. strumarium, Acalypha australis, Erigeron canadensis, Echinochloa crus-galli, and Vicia tetrasperma. Zonation of vascular hydrophytes and hygrophytes was as followers: Salix glandulosa, S. koreensis, S. nipponica were distributed in the region of land which water table is low, and Persicaria maackiana, Persicaria hydropiper, Scirpus radicans were distributed in the understory. And emergent plants such as Phragmites communis and Scirpus karuizawensis, floating-leaved plant such as Trapa japonica, submersed plant such as Ceratophyllum demersum, and free floating plant such as Spirodela polyrhiza formed the zonation from shoreline to water. The specified wild plants designated by the Korean Association for Conservation of Nature, Ministry of Forest, and Ministry of Environment were not distributed in the study area. It was expected that Haepyeong Wetland worthy of conservation contributed purifying water pollution, giving habitats of many lifes, and providing beautiful scenes of the river.

• Korean Journal of Weed Science
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• v.14 no.2
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• pp.120-127
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• 1994

To establish an efficient herbicide screening method for purple nutsedge(Cyperus rotundus) control, its sprouting characteristics, tuber production and responses on several herbicides were investigated under greenhouse condition. The tubers stored at $4^{\circ}C$ after sterilization with the diluted prochloraz(Spotac) solution showed higher sprouting than the non-sterilized did. The harvested tubers were not dormant, and the sterilized tubers which stored at low temperature had a sprouting capability of about 80% after 6 months. If the fresh weight of purple nutsedge tubers was decreased to below 48%, they could not sprout. However, the tubers soaked in water and then stored at low temperature could sprout by 88% even 6 months later. Sprouting and initial growth of tuber were much better at $35^{\circ}C$-day/$25^{\circ}C$-night than at 30/$20^{\circ}C$ or 25/$15^{\circ}C$. The half-sected tubers, which were prepared by setting the intact tuber of above 1.2g latitudinally, were shown similar initial growth to the intact but those sected crucifically were not. These results suggest that the half-sected tuber itself can be used as a material on herbicide screening. About 1000 tubers could be harvested when 10 tubers planted in a pot($56{\times}35{\times}16cm$) filled with the artificial soil were cultivated in greenhouse of $35^{\circ}C$-day/$25^{\circ}C$-night for 3 months(April-July, 1993). Chlorimuron, Bentazon and Norflurazon were selected as the standards for the screening because of providing relatively effective control on purple nutsedge in both soil-surface and foliar spray treatment.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.408-414
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• 2011

The purpose of this study was to find out optimum cultivated regions for rice organic farming. The organic and conventional rice as control were grown in three different places : secluded hill paddy field for Hapcheon, normal rural paddy field for Sancheong, and suburban paddy field for Jinju from 2005 to 2006. In secluded hill paddy field, the organic material and pesticide to control pest and disease were input twice for organic and conventional rice cultivation. However, in normal rural and suburban paddy field, those were input three times for organic and conventional rice cultivation. The occurrence of sheath blight in organic farming was higher than in conventional farming. Whereas brown planthopper population per 20 plant was significantly high 10.1~19.5 for conventional farming compared with 4.4~10.0 for organic farming. For that reason, the density of the brown planthoppers was higher in organic farming than those in conventional farming. Dominated weeds occurred in organic and conventional paddy field were namely Monochoria vaginalis, Ludwigia prostrata, and Cyperus difformis. The population per 20 plant and dried weight per $m^2$ of weeds were higher in 121 and 50.5 g for organic paddy field. The productivity of rice in different cultivated regions for organic farming was $2.96Mg\;ha^{-1}$ in hill paddy field, $4.03Mg\;ha^{-1}$ in normal rural and suburban paddy field. Toyo-taste value and ratio of perfect grain of milled rice were not different by cultivated regions in both farming system.

• Journal of Wetlands Research
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• v.25 no.2
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• pp.145-158
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• 2023

Constructed wetlands (CWs) are effective technologies for urban wastewater management, utilizing natural physico-chemical and biological processes to remove pollutants. This study employed a bibliometric analysis approach to investigate the progress and future research trends in the field of CWs. A comprehensive review of 100 most-recently published and open-access articles was performed to analyze the performance of CWs in treating wastewater. Spain, China, Italy, and the United States were among the most productive countries in terms of the number of published papers. The most frequently used keywords in publications include water quality (n=19), phytoremediation (n=13), stormwater (n=11), and phosphorus (n=11), suggesting that the efficiency of CWs in improving water quality and removal of nutrients were widely investigated. Among the different types of CWs reviewed, hybrid CWs exhibited the highest removal efficiencies for BOD (88.67%) and TSS (95.67%), whereas VSSF, and HSSF systems also showed high TSS removal efficiencies (83.25%, and 78.83% respectively). VSSF wetland displayed the highest COD removal efficiency (71.82%). Generally, physical processes (e.g., sedimentation, filtration, adsorption) and biological mechanisms (i.e., biodegradation) contributed to the high removal efficiency of TSS, BOD, and COD in CW systems. The hybrid CW system demonstrated highest TN removal efficiency (60.78%) by integrating multiple treatment processes, including aerobic and anaerobic conditions, various vegetation types, and different media configurations, which enhanced microbial activity and allowed for comprehensive nitrogen compound removal. The FWS system showed the highest TP removal efficiency (54.50%) due to combined process of settling sediment-bound phosphorus and plant uptake. Phragmites, Cyperus, Iris, and Typha were commonly used in CWs due to their superior phytoremediation capabilities. The study emphasized the potential of CWs as sustainable alternatives for wastewater management, particularly in urban areas.