• The Korean Journal of Ecology
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• v.7 no.2
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• pp.67-73
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• 1983

Jeju-Do is a volcanic island of which climate is very warm and humid, but Opuntia lanceolata Haw, showing CAM metabolism is growing at Wolyung-Ri, Hanrim-Eup, Jeju-Do. Annual productivity of Opuntia was 696.47g/m2/yr and 533.47g/m2/yr at two populations on the seashore respectively and 414.92g/m2/yr on the basalt wall of a village. Stem area index was 13.74, 6.93, and 9.30 at each population which are higher values than average range of leaf area index. The standing crop was the highest at the second cladode from the cladode showed little difference at most chemical properties of P, K, Ca and Na. Total nitrogen contents were the most at the youngest cladode and the lest at the oldest one. Soils were infertile of which organic contents were 1.5% and 5.0% on the seaside and the basalt wall respectively. The soil on the basalt wall contained little water whose water contents were 0.9% and at seashore population 15.12% of water contents were. Furthermore high exchangeable Na contents in soil added waer deficiency.

• Journal of the Korean Applied Science and Technology
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• v.37 no.6
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• pp.1489-1495
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• 2020

Gotjawal, Jeju Island, Korea is a lava-formed forest with low soil content that is unique in the world. Around 6 percent of the Jeju Iand is classified as a lava-based specific forest. The forest has been gradually disappearing during the last several decades, with approximately one half having been destroyed. Our study undertakes a detailed analysis of the landscape of the lava subsidence, and describes the fungi, vegetation, and soils of Cheongsu Gotjawal. Soil samples from the Gotjawal were collected, and soil analyses as well as pyrosequencing of the internal transcribed spacer gene for fungal communities were performed. Soil fungal communities are represented by Discisedars, Fusarium, Pleochaeta, and Fuscoporia genera. Endemic vegetation of the Gotjawal includes the plants Pleris critical, Machilus japonica, Quercus glauca, Arachniodes aristata, and Neocheiropteris ensata. Results of soil analysis indicate sandy loam with 31.70% organic matter, and 1.36 mg/kg of total nitrogen. This fundamental information can help understand the invaluable and unique nature of Cheongsu Gotjawal, and the necessity for more studies on Gotjawal.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.2
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• pp.135-140
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• 1988

A laboratory experiment was conducted to find out the number of soil microorganisms, identification and enumeration of soil microbial species on the mineral and volcanic ash soil with different cropping system of the Jeju Island. The results obtained were summarized as follows: 1. The number of bacteria was high in mineral soil with rotation of upland crops than that of volcanic ash soil with continuous cropping system. 2. According to identification of soil bacteria, the most of bacteria were composed to short rod with Gram negative. Among the bacteria species, Rhizobium spp. and Flavobacterium spp. were most high population in both of mineral and volcanic ash soil. 3. The number of fungi in mineral soils were reduced by the rotated cultivation of upland crops but no significant differences were observed in volcanic ash soil with continuous cropping system. On the other hand, Aspergillus spp., Fusarium spp., and Penicillium spp. were most high population in both of mineral and volcanic ash soil. 4. Comparing of the number and species ot microorganism to the cash crops soil in main land, about 10 to 100 times for bacteria and more than two times for the number and species of fungi were lowered in Jeju Island soil.

• Economic and Environmental Geology
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• v.35 no.6
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• pp.491-508
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• 2002

While about 80% of Jeju soils are classified as Andisols, the soils derived from volcanic ash in Dangsanbong are not Andisols. There is a significant difference of precipitation in localities of Jeju island. The study area is characterized by the lowest amount of annual rainfall in Jeju Island, and by the layered silicates as dominant solid phase in clay fraction. The purpose of this study was to characterize the mineralogy of the non-Andie soils in detail, especially hydroxy-interlayered silicates. Two major soil horizons are recognized in the soil profile developed in the Dangsanbong area, which can be designated as A and C. The soil pH($H_{2}0$), ranges from 6.6 to 7.3 increasing with depth, is higher than that of typical Andisols(pH<6.0). While the pH(NaF), ranges from 9.49 to 9.81, indicates that significant amount of amorphous phases might be present as exchanging complexes. It is estimated to about 1.542.88 wt% by using chemical selective dissolution. The organic content of surface horizon is about 2 wt%. This soil are composed of quartz, feldspar and olivine as major constituents with minor of silicate clays. Quartz is frequently observed in A and distinctly decreases in its amount with depth, while olivine is dominant phase in C and rarely observed in A. In the <0.2$\mu\textrm{m}$ size fraction, smectite and kaolinite/smectite interstratification are dominant with minor of illite. The amounts of smectite decrease with depth, while the amounts of kaolinite/smecite interstratification increase with depth, which indicates the trend of mineral transformation with increasing the degree of weathering. The proportion of kaolinite in kaolinite/smectite interstratification is about 85%, and is not changed significantly through the profile. In the 2-0.2$\mu\textrm{m}$size fraction, vermiculite, smectite, illite and kaolinite are major components with minor of chlorite. Most of chlorite are interstratified with smectite. Chlorite which is not interstratified with smectite occurs only in surface horizon. The proportion of the chlorite in the chlorite/smectite interstratification is 59-70(%) and increases with depth. Hydroxy-interlayered vermiculite(HIV) with hydroxy-Fe/AI in their interlayers occurs in both A and C horizon. The amounts of hydroxy-Fe/AI decrease with depth. Hydroxy-interlayered smectite(HIS) of which interlayers might be composed of hydroxy-Mg/Al occurs only in C horizon. As the results of mineralogical investigation for the soil profile in the study area, clay minerals might be changed and evolved through the following weathering sequences: 1) Smectite Kaolinite, HIS, Vermiculite, 2) Vermiculite HIV Chlorite.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.4
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• pp.247-262
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• 1979

Majority of reclaimable soils in hillside lands in Korea are red yellow soils, with exception in Jeju island, where most of reclaimable hillside lands are composed of volcanic ash soils. Songjeong, Yesan and Samgag series are the major soil series of red yellow soils which are available for the reclamation. When observed in the fields, they are distinguished as reddish brown clay loam, red yellow sand loam and yellowish brown sand loam. They have moderately good physical properties but their chemical properties are generally poor for crop cultivations. The chemical properties of red yellow soils, as compared to long time cultivated (matured) soils, are characterized by very low pH, high in exchangeable Al content and phosphorus fixation capacity. Also extraodinary low available phosphorus and organic matter contents are generally observed. On the other, the chemical properties of volcanic ash soils are characterized by high armophous Fe and Al hydroxides and organic matter contents, which are the causative factors for the extremely high phosphorus fixation capacity of the soils. The phosphorus fixation capacity of volcanic acid soils are as high as 5-10 times of that of red yellow soils. Poor growth of crops on newly reclaimed red yellow soils are mainly caused by very low available P and pH and high exchangeable Al. Relatively high P fixation capacity renders the failure of effective use of applied P when the amount of application is not sufficient. Applications of lime to remove the exchangeable Al and relatively large quantity of P to lower the P fixation capacity and to increase the available P are the major recommendations for the increased crop production on red yellow hillside soils. Generally recommendable amounts of lime and P to meet the aforementioned requirements, are 200-250kg/10a of lime and $30-35kg\;P_2O_5/10a$. Over doses of lime. frequently induces the K, B, arid Zn deficiencies and lowers the uptake of P. In volcanic ash soils, it is difficult to alter the exchangeable Al and the P fixation capacity by liming and P application. This may be due to the peculiarity of volcanic ash soil in chemical properties. Because of this feature, the amelioration of volcanic ash soils is not as easy as in the case of red yellow soils. Application of P as high as $100kg\;P_2O_5/10a$ is needed to bring forth the significant yield response in barley. Combined applications of appropriate levels of P, lime, and organic matter, accompanied by deep plowing, results in around doubling of the yields of various crops on newly reclaimed red yellow soils.

• Journal of the Korean earth science society
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• v.28 no.7
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• pp.925-935
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• 2007

Water sources in volcanic Jeju Island are almost entirely dependent on groundwater because there are actually no perennial streams or rivers due to the permeable nature of surface soils derived from basaltic or trachytic rocks. Uncontrolled development of groundwater resulted in substantial water-level decline, groundwater pollution, and seawater intrusion in several places of the island. To maintain its sustainable groundwater, the provincial government has declared some parts of the island as the Special Groundwater Conservation/Management Area since 1994. Hence, all the activities for the groundwater development in the area should obtain official permit from relevant authorities. Furthermore, to acquire information on groundwater status, a network of groundwater monitoring was established to cover most of the low land and coastal areas with the installation of automatic monitoring systems since 2001. The analysis of the groundwater monitoring data indicated that the water levels had decreased at coastal area, especially in northern part of the island. Moreover, very high electrical conductivity (EC) levels and their increasing trends were observed in the eastern part, which was ascribable to seawater intrusion by intensive pumping in recent years. Water level decline and EC rise in the coastal area are expected to continue despite the present strict control on additional groundwater development.

• Journal of the Korean Geosynthetics Society
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• v.14 no.2
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• pp.89-94
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• 2015

In this study, the mixed soil with an optimum mixed ratio was suggested in order to recycle the powdered sludge of basalt in Jeju Island as the impermeable liner materials. As the results of soil laboratory tests, the grain size of the powdered sludge of basalt is less than 0.1mm and the powdered sludge was classified into ML or CL category in accordance with the Unified Soil Classification System (USCS). Also, the grain size of natural soils is ranged from 0.1 mm to 10 mm and the soils were classified into SW category in USCS. To select the optimum mixed ratio of powdered sludge, the variable permeability test was performed to various mixed soils with different powdered sludge amount under both optimum compaction and field conditions. As the results of permeability tests, the coefficient of permeability of mixed soils was decreased with increasing the mixed ratio of powdered sludge, and the mixed soil with mixed ratio of 60% has the minimum coefficient of permeability. Therefore, the optimum mixed ratio of powdered sludge is 60% for recycling the powdered sludge of basalt as the impermeable liner materials.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.2
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• pp.59-66
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• 2001

In order to determine the influence of nitrogen on agronomic characters, forage yield and quality, a Kenaf was cultured on the volcanic ash soil at the Experimental Farm of Cheju national University under the seven levels of nitrogen rates(0, 50, 100, 150, 200, 250kg/ha) from April 25 to Dec. 25, 1999. The plant height increased by increase of nitrogen rate, showing longest 250kg/ha with 286.6cm and shortest at no application plot with 255.7cm. The difference on leaf number, leaf withering number, stem diameter and branches number by nitrogen rate showed a similar tendency to the plant height. Increasing N rate from 0 to 250kg/ha fresh forage yield form 55.8 to 99.8MT/ha, dry matter (DM) yield from 8.8 to 15.8MT/ha, crude protein(CP) yield form 1.2 to 3.1MT/ha, total digestible nutrients (TDN) yield from 3.8 to 8.6MT/ha. However, no significant differences in these yields were found between 200 and 250kg N/ha. Nitrogen uptake increased form 192.9 to 496.2 kg/ha but N use efficiency decreased form 95.0 to 66.6 kg DM$^{a}$ /kg N with increasing from 0 to 250 kg/ha. As N rate increased from 0 to 250kg/ha, leaf and stem out of CP, crude fat (CF), nitrogen free extract (NFE), TDN contents increased from 20.1% to 25.8% and from 9.7% to 12.4%, from 5.6% to 8.1% and from 3.3% to 4.4%, from 36.1% to 40.2% and from 21.9% to 32.4%, from 59.3% to 75.0% and from 32.2% to 38.2%, respectively, while leaf and stem out of crude fiber decreased from 18.5% to 16.7% and from 51.5% to 39.3%. Based on the these findings, the optimum N rate for forage production of kenaf seems to be about 200 kg/ha in atmospheric phenomena and volcanic ash soils of jeju island.

• Korean Journal of Agricultural Science
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• v.7 no.1
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• pp.52-58
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• 1980

This study was conducted to detect copper which is considered in the soils of orchards, since copper fungicide has been applied to fruit trees. Soil samples taken from the fields of the chief producing districts of apple (Chungju, Yesan, Daegu), pear (Yangju, Bucheon, Seonghwan) and citrus (Seogypo in Jeju island) were analysed by an atomic absorption spectrophotometer. The results obtained were summarized as follows ; 1. In orchards of apple, the amount of copper of soils from Yesan, Chungju and Daegu were ranged 2.6-171.3ppm, 2.2-136.1ppm and 14.3-134.6ppm, respectively. Very little copper was detected from the soils in the field which has been cultivated for less than 20 years. About 100ppm and 130-170ppm of copper were detected in the field which has been cultivated for 30 years and for 50-60 years, respectively. Most of the copper was detected in the surface layer of soils (0-10cm), while very low content of copper was detected in the deeper layer of soils (10-20cm). 2. In orchards of pear, 20-30ppm of copper was detected from the surface of soils in the field which has been cultivated for more than 30 years and the highest level of copper, 36.8ppm, was detected from Yangju area. The amount of copper of soils from Yangju, Seonghwan and Bucheon were ranged 3.6-36.8ppm, 9.7-19.4ppm and 3.6-24.7ppm, respectively. 3. In orchards of citrus of Jeju island, only trace amount and 23-38ppm of copper were detected in the fields cultivated for 15 years and 20-30 years, respectively. The highest level of copper, 57ppm, was detected from the surface layer of soils in the field which has been cultivated for 35 years, but in most of the soil samples tested, only the natural background level of copper, about 20ppm, was detected. 4. The levels of copper residue in all the soil samples tested were lower than the tolerance level (125ppm of copper which is extracted in 0.1N-HCl solution), except those of copperr residue, 130-170ppm, that were detected from the orchards of apple which have been under cultivation for 50-60 years. Hence no problem for the farming could be speculated with the present concentration of copper analysed.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.3
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• pp.145-152
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• 2002

The composition of primary minerals in the rocks and secondary minerals of clay fractions of the soil developed on the cinder cones in the foot of Halla Mt., Jeju Island was investigated. The effects of parent materials on the physico-chemical properties and mineralogical characteristics were evaluated by XRD, DTA with the chemical composition of $H^+$ saturated clays. The main rock-forming minerals of a residual cinder cones were plagioclase with subsidiary minerals of hematite, gibbsite and quartz in the red cinder cone and of augite, quartz, feldspars and olivine in black cinder cone. It is demonstrated that ignition loss and sesquioxides content were higher in the red cinder soil than black cinder, which was resulted in the intermittent eruption of volcanic activity. For the chemical analysis of whole soils, $SiO_2/Al_2O_3$ ratio was increased from 2 to 3, but Ignition loss is decreased and $K_2O$ content are very low with increasing the soil depth in regard to the composition and kinds of clay minerals. No clay formation from micas mineral were in volcanic ashes. Dominant clay minerals of the cinder cone soils as a black and red cinder cone soil were allophane with some quartz and feldspars, while vermiculite, illite, kaolin were coexisted as a subsidiary minerals. But the red cinder cones soils had more hematite and gibbsite of the clay fractions than the black soils with magnetite. The exothermic pick of DTA at about $660^{\circ}C$ for cinder cone soils might be corresponded the oxidation magnetite to hematite reation. With regarding to the compositions of mineral detected by X-ray diffractogram and the properties of minerals by D.T.A thermogram, the dominant clay mineral was allophane of the cinder cone soils with some ferrous compounds, red colour of the cinder cone soils which are originated in hematite.