• Economic and Environmental Geology
• /
• v.32 no.4
• /
• pp.323-337
• /
• 1999

Late Cretaceous to early Tertiary volcanic rocks in the Kyongsang basin exhibit high-K calc-alkaline characteristics, and originated from the magmatism related genetically to subduction of Kula-Pacific plate. They represent HFSE depletion and LlLE enrichment characteristics as shown by magmas related to subduction. Early studies on the depth of magma generation has been estimated as 180-230 km based on K-h relation should be reevaluated, because the depth of peridotite partial melting with 0.4 wt. % water is 80-120 km at subduction zone, and subducting slab in premature arc can melted even lower than 70 km. Moreover the increase of potassium contents depends on either contamination of crustal material and fluids of subducting slab or low degree of partial melting. If the inclination of subduction zone is 30 degrees and the depth to the Benioff zone is 180-230 km, the calculated distance between the volcanic zone and trench axis would be 310-400 km. It is unlikely because the distance between the Kyongsang basin and trench during late Cretaceous to early Tertiary is closer than this value and not comparable with generally-accepted models in subduction zone magmatism. $K_{55}$ of the volcanics in the Kyongsang basin is 0.3-2.3 wt.% and the average indicate that the depth ranges between 80-170 km on the diagram of Marsh, Carmichael (1974). Fractionation from garnet lherzolite, assumed the depth of 180-230km, is not consistent with the REE patterns of the volcanoes in the Kyongsang basin. Futhermore, the range of depth suggested by many workers, who studied magmatism related to subduction, imply shallower than this depth. Crustal thickness calculated by the content of CaO and $Na_2O$ is about 30 km and about 35 km, respectively. Paleo-crustal thickness during late Cretaceous to early Tertiary times in the Kyongsang basin inferred about 30 km calculated by La/Sm versus LaJYb data, which is also supported by many previous studies.

• Korean Journal of Weed Science
• /
• v.4 no.1
• /
• pp.69-78
• /
• 1984

This study was conducted to select herbicides effective for upland crops and to investigate the cause of crop injury in peanut cultivated with mulching. Crop such as radish (Raphanus acanthiformis Moor.), Chinese cabbage (Brassica raps L.), soybean (Glycine max Merr.), Peanut (Archis hypogaea L.), and marsh mallow (Malva olitoria Nakai) were tolerant to napropamide [2-(${\alpha}$-naphthoxy)-N, N-diethylpropionamide], alachlor [2-chloro-2', 6'-diethyl-N-(methoxymethyl) acetanilide], trifluralin (${\alpha},{\alpha},{\alpha}$-trifluoro-2, 6-dinitro-N, N-dipropylp-toluidine) and nitrofen (2,4-dichlorophenyl-p-nitrophenylether). Napropamide, diphenamide (N, N-dimethyl-2, 2-diphenylacetamide) and alachlor were safe for red pepper (Capsicum annuum L.), eggplant (Solanum melongena L. and tomato (Lycopersicon esculentum Mill.), while trifluralin, nitrofen and chlonitrofen (2,4,6-trichlorophenyl-4-nitrophenyl ether) could be used for water melon (Citrullus battich Forsk.), carrot (Daucus carota L.) and lettuce (Lactuca scariola L.) without crop injury. Out of nine major weed species studied, Capsella bursa-pastoris Medicus was the most resistant species to the herbicides tested. Napropamide and alachlor could not control P. hydropiper, while P. oleracea and C. album were tolerant to diphenamide :and alachlor, respectively. Urea herbicides such as methabenzthiazuron [3-(2-benzothiazolyl)-1,3-dimethylurea], linuron [3-(3, 4-dichlorophenyl~l-methoxy-i-methyl urea], and isoproturon [3-(4-isopropylphenyl) -1, 1-dimethylurea]gave a great injury to the crops studied. The weeding effect was greater for broadleaf weeds than for grasses. Isoproturon and linuron provided good selectivity for marsh mallow and carrot, respectively. In peanut, the crop injury caused by Four herbicides studied was greater when cultivated with mulching than when cultivated without mulching. With dinitroaniline herbicides the crop injury decreased as the gaseous herbicide was removed out of mulching. Alachlor gave little phytotoxicity to peanut grown under mulching condition and nitralin [4-(methylsuphonyl)-2, 6-dinitro-N, N-dipropylaniline] showed less toxicity to the peanut than pendimenthalin (3,4-dimethyl-2, 6-dinitro-N-1-ethyl propylaniline) and trifluralin.

• The Korean Journal of Pesticide Science
• /
• v.2 no.2
• /
• pp.102-107
• /
• 1998

The objective was to know if seed potato farmers in Kangwon alpine area control weeds effectively and use herbicides properly to control weeds. Seed potato farmers in Pyongcbang, Hoengsong, and Kangnung have noxious weeds, such as marsh pepper, lambsquarters, barnyard grass, mugwort, asiatic dayflower, hairy carbgrass, ladysthumb, common chickweed, field horsetail, and common purslain, in their farmyard. These are controlled by a combination of physical and chemical weed control methods. However, several weeds such as marsh pepper, field horsetail and, mugwort are poorly controlled by 2-fold amount of several herbicides, including paraquat, pendimethalin, and metribuzin (58% of the answered). Herbicides are not selected and used in a proper manner by seed potato farmers: most of farmers selected herbicides by their experience (51% of the answered) and dealers recommendation (34% of the answered), while only a few farmers of the answered took advantage of the Farmers Handbook for Herbicide Application. In addition, the selected herbicides, including non-registered ones such as paraquat and fluazifop-butyl, are applying three to five years in a succession. With these improper selection and usage of herbicides, sixty-seven percent of the answered farmers have experienced crop damage and seventy-five percent have poisoning. We conclude that a systemic educational program for the proper selection and use of herbicides is needed for seed potato farmers in Kangwon alpine area.

• The Korean Journal of Malacology
• /
• v.17 no.1
• /
• pp.45-55
• /
• 2001

Gametogenes, reproductive cycle, first sexual maturity(biological minimum size), sex ratio and larval development of the marsh clam Corbicula japonica were investigated monthly by histological observations. Samples were collected in brackish water of Gokgang stream, Kyungsangbuk-Do, Korea, from August 1997 to July 1998. Sexuality of Corbicula japonica is dioecious and the species are an oviparous clam. The gonads are irregularly arranged from the sub-region of mid-intestinal gland in visceral cavity to reticular connective tissue of foot. The ovary is composed of a number of ovarian sac which are branched arborescent. Oogonia actively proliferate along the germinal epithelium of ovarian sac, in which young oocytes are growing. The testis is composed of a number of testicular tubules, and the epithelium of the tubule has function of germinal epithelium, along which spermatogonia actively proliferate. A great number of undifferentiated mesenchymal tissue and eosinophilic granular cells are abundantly distributed between developing oocytes and spermatocytes in the early developmental stages. With the further development of the ovary and testis these tissue and cells gradually disappear. Then the undifferentiated mesenchymal tissue and eosinophilic granular cells are considered to be related to the growing of the oocytes and spermatocytes. The spawning period is from July to September, and the main spawning occur between July and August when seawater temperatures reach above 22$^{\circ}C$. The reproductive cycle of this species can be divided into five successive stages; early active (February to April), late active (May to July), ripe (June to September), partially spawned (July to September), degenerative (September to October) and resting stage (October to February). Percentages of first sexual maturity of female and male clams ranging in length from 10 mm to 12 mm are over 50% and 100% for clams over 16.0 mm in shell length. Fertilized eggs or Corbicula japonica were 80-90 ${\mu}{\textrm}{m}$ in diameter. In the early embryonic development of C. japonica, the appearance of polar body, trochophore and D-shaped veliger were observed around 40 min., 27 hours and 4 days after spawning, respectively, at a water temperature of 26.5-28.$0^{\circ}C$. The size of larvae of early umbo stage was about 185-210 ${\mu}{\textrm}{m}$ in shell length, 160-180 ${\mu}{\textrm}{m}$ in shell height around 7 days after fertilization. The correlation of relative growth between the culture day (D) and shell length (SL) was expressed by the following simple formula from D-shaped veliger to metamorphosing stage; SL = 13.300D + 209.36($r^2$= 0.9078).

• Journal of Wetlands Research
• /
• v.9 no.2
• /
• pp.45-55
• /
• 2007

Flora, actual vegetation map, distribution area by the life form, primary productivity and annual primary production by the vascular hydrophytes and hygrophytes were investigated in the Upo wetland, Changnyeong-gun, Gyeongsangnam-do, Korea from May 2005 to March 2006. The flora of Upo, Mokpo, Sajipo, Jokjibyeol, Topyeongcheon upstream, and Topyeongcheon downstream were composed of 263, 233, 244, 182, 190, and 178 taxa, respectively. The flora of total study area was 85 families, 224 genera, 287 species, 42 varieties, 4 form, or total 333 taxa. Among them, hydrophytes, hygrophytes, and others were 38, 108, and 187 taxa, respectively. The life form of the vascular hydrophytes was classified as 20 taxa of emergent plants, 6 taxa of floating-leaved plants, 5 taxa of free-floating plants, and 7 taxa of submersed plants, respectively. There were 27 plant communities including pure population, mixed population, and etc. It is also found that Trapa japonica-Ceratophyllum demersum community occupies 60.64 ha, the largest area, and Salvinia natans-Ceratophyllum demersum community 32.91 ha, Zizania latifolia community 30.05 ha, and that the area of free-floating plants was the largest as 172.6 ha(47.9%) on the basis of life form. Total annual primary production of the vascular hydrophytes and hygrophytes was 1,383.3ton. That of the emergent hydrophytes was the most as 564.1 ton(40.8%), and those of the free-floating, floating-leaved, and the submersed were 484.1 ton(34.9%), 146.7 ton(10.6%), and 1.3 ton(0.5%), respectively, and the hygrophytes was 182.1 ton(13.2%). Since most plant species are fairly adapted to the present marsh environment, bad influences and change of species composition are expected by the artificial influences on the wetland such as fragmentation, reclamation, and introduction of the exotic species. Therefore, schemes and counterplans for the conservation and preservation of the marsh are demanded.

• Journal of the Korean association of regional geographers
• /
• v.14 no.1
• /
• pp.1-18
• /
• 2008

If there is no choice but to be urbanized, we should examine how human interference has had influences on the area to keep the river environment safe and stable. This study is aimed at finding improvement by examining the effect of human interference in Gapcheon river in Daejeon, which is developing fast. Distinctive features of human interference in Gapcheon river are followings. First, middle and upper reaches of Gapcheon river are being maintained and restored focusing on flood control but are scheduled to develop city and channel. Second, the rear area of middle and lower reaches of Gapcheon river is already developed into an urban district and solidified into artificial stream for leisure activities installing the artificial structure for fun. Third, lower reaches of Gapcheon river are in an unstable condition because of straightening waterway and developing rear area of river. Up to now, geographical features and bio-diversity of Gapcheon river has been ruined by the artificial management of river centered for technical engineering. From now on, followings should be considered for management of urban river. First, it is focused on maintaining eco system by itself than usage for human. Second, natural features of rear area of river should be taken into consideration and should be preserved before developing urban city and hills, back marsh, channel deposit and swamp to directly have an influence on river.

• Korean Journal of Environment and Ecology
• /
• v.25 no.6
• /
• pp.846-852
• /
• 2011

This study researched the spawning sites of Kaloula borealis in a large number of wetlands in Jeju Island between May and August from 2007 to 2010. Based on the surveys, we discovered the locations of their habitats by investigating their calls from a rainy night to the next day and where their spawning sites were by ascertaining the existence of their eggs and tadpoles. According to the results, 83 wetlands were used as spawning sites across Jeju Island. A large number of wetlands were found to be permanent wetlands for Kaloula borealis. In addition, 81.9% of the wetlands in Jeju Island were found to be at an altitude of 150m or lower, and they spawned in shallow water not more than 50cm in depth. By region, 54 wetlands were in Jeju-island 29 wetlands were in Seogwipo-si. One of the reasons that Seogwipo-si has less wetlands than Jeju-si is that there are more orchards in Seogwipo-si than Jeju-si; accordingly, wetlands in Seogwipo-si were found to be more destroyed by farming. In the case of Seongsan-eup, a reedy marsh stretches out widely so that spawning sites were well preserved compared to other regions. This research will provide useful data for sustaining the population of Kaloula borealis by protecting their spawning sites from development, by offering habitats, and restoring spawning sites, which have become severely damaged and destroyed.

• Journal of Wetlands Research
• /
• v.18 no.4
• /
• pp.488-498
• /
• 2016

In order to assess the role of aeration in stormwater wetlands, oxygen supply and consumption in a wetland treating runoff from livestock farms were estimated and analyzed. Furthermore, oxygen mass balance was conducted during day time and night time. Internal production by algal photosynthesis dominated the oxygen production particularly in the shallow marsh due to the large amount of algae. Consequently, algal respiration was also the major oxygen depletion element with nitrification and biodegradation estimated as 5.35% and 6.43% of the total oxygen consumption. This excessive portion of oxygen consumption by algae was associated to the highly turbid water caused by the resuspension of sediment particles in the aeration pond, which also affected the subsequent wetland. Moreover, an abundance of oxygen was estimated during the day indicating that oxygen produced by algal activity is sufficient to meet the oxygen demand in the wetland. Thus, supplemental aeration was deemed not necessary at daytime. In contrast, oxygen was greatly depleted at night when algal photosynthesis stopped which induced denitrification. Therefore, it was suggested that supplemental aeration may be operated continuously instead of intermittently to avoid oxygen deficit in the wetland at night or it may be stopped entirely to further enhance denitrification.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.9
• /
• pp.1335-1339
• /
• 2010

A total of 550 samples were analysed for nitrate contents using HPLC-UV. Nitrate contents of leaf vegetables were higher than those of root vegetables and fruit vegetables. The average nitrate content of the radish leaves (4875.8 mg/kg) was the highest, followed by marsh mallow (4711.7 mg/kg), crown daisy (4546.9 mg/kg) and vitamins (4239.5 mg/kg). The nitrate content in fruits of strawberry and banana averaged at 24.0 mg/kg and 438.5 mg/kg, respectively. Nitrate was not detected in other fruits. In fruiting vegetables nitrate contents were less than 1000 mg/kg. In onion, lotus root and radish, nitrate contents were 253.7mg/kg, 352.4mg/kg and 2849.0 mg/kg, respectively, with no detection in garlic. Nitrate contents in mushrooms were less than 100 mg/kg.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.2 no.1
• /
• pp.48-57
• /
• 1999

This study was aimed to establish biotop unit of the mixed rural city for the method and process of the biotop mapping system. Survey site was Maejuri of Seunghwan(158ha), Gisanri of Mokchon(132ha) and Namkwanri, Pungsemeon(214ha). So the main process was divided by 4 schemes such as Biosphere, Geosphere, Antrosphere and Evaluation. Also the GIS(geographic information system) was used to make the database of the biotop and biotop complex, analyze the cross-combinations and analyze the characters of the biotop. Biotop mapping system had 5 steps which were proceeded with research goals, constructing the spatial database and attribute database, classifying the 3 types of biotop such as tree/shrub biotop, grass biotop and wetland biotop, cross-analyzing 3 biotop types with land use, habitat characters, relief characters and danger/disturbance elements and evaluating the 3 types of biotop. The results of applicating the biotop mapping system on the research site as followings : The distributions of the land uses in Maejuri, Seunghwan eup in Chonan city were recorded by forest(29.8%), orchard(14.1%) and landscaping around building site(9.0%). Gisanri, Mokchonmeon were composed of forest(64.5%), farm(12.8%) and Namkwanri, Pungsemeon were concentrated rice field(39.6%), dwell district(22.4%). The Tree/Shrub biotop type was reclassed by the forest type, natural and artificial decidous type with natural coniferous. The Grass biotop type was reclassed by the wild grassland type, garden type and peddy field with wild grassland. The distributions of the wet land were pointed high at the wet land type with reed marsh and edge vegetation around wet land in reservoir and river. The evaluation of the mapped bitopes was completed to the following aspect, "amenity" and "environmental education". A high value of 7.13%(1 class) was shown Maejuri, Seunghwan eup. The regions which were studied synthetically are divided to three parts ; the area where have nature and art mixed(Seunghwan), the area which is more artificial because people inhabit there for a long time(Pungsemeon) and the area that ecological environment is threatened by development pressure(Mokchonmeon). Therefore, ecological restoration plan which depends on specific property of the regions should be established. Also the interdisplinary researches were needed to develop the BMS(Biotop Mapping System) in Korea because of the differences with Germany, England's ecological habitat conditions.