• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.4
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• pp.305-319
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• 2000

A total of 50 diatom species and 1 subspecies belonging to 31 genera except Chaetoceros resting spores were identified in the 45 sediments subsampled from a gravity core GH98-1223 collected from the western Hokkaido Island located in the northeastern East Sea (Sea of Japan). The most dominant species is Thalassionema nitzschioides (Grunow) Hustedt, ranging 29 to 59% of the total assemblages, and most species including Denticulopsis seminae (Simonsen and Kanaya) Simonsen and Pseudoeunotia doliolus (Wallich) Grunow were less than 5% in average. Frequencies of cold-water species are generally higher than those of warm-water species and the vertical distribution of cold-water species was largely opposite to that of warm-water species in spite of ecological habitat difference. Frequency of cold-water species, D. seminae is reverse to that of P. doliolus, an indicator of the Tsushima Warm Current, which is consistent with diatom temperature value (T$_{d}$ value). The variation of T$_{d}$ values shows that the upper part of core with greater-than-average T$_{d}$ values represents postglacial warming trend. These T$_{d}$ values clearly demonstrate that the study area located in the northern part of the East Sea is gradually influenced by Tsushima Warm Current. In addition, the zig-zag variation in the lower part reflects the unstable seawater for diatom habitat. Chaetoceros resting spores indicating productivity and upwelling was 5.3 to 40%, with maximum peak at 80 cm. Chaetoceros resting spores/Chaetoceros vegetative cells, an indicator of relative amounts of biogenic material in the sediments was high at the upper 80 cm level, corresponding to the change of T$_{d}$ values. On the basis of diatom assemblages, the northeastern part of East Sea has experienced the effects of Tsushima Warm Current during the postglacial period of Holocene, which is similar to the modem climatic environment. However, the variation of P. doliolus reflects that the intensity of Tsushima Warm Current has been oscillated in the East Sea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.2
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• pp.30-37
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• 1964

Experiments were carried out to clarify the relationships between seed yields and some ecological characteristics, seed yields and some morphological characteristics, and the relationships among the varietal yields on the several sowing plots when grown under different climatic conditions. Twenty-four soybean varieties were used as the material, selected at random from 138 varieties which were cultivated the year before. These varieties were grown in the Experimental Farm, Chinju Agricultural College, Kyung Sang Namdo, Korea, and seed sowing was conducted at 5 times, from April to July, in 1962 and 1963. The results obtained are summarized as follows: 1. Correlations between seed yields and some ecological characteristics on the sowing date bases are shown in Table 1. Among some ecological characteristics, it was observed that there wert close relationships between seed yields and days to flowering, and between seed yields and the total growing length, except on the late sowing, i.e. July sowing plots, However, there was no clear correlation between seed yields and durations of flowering, and between seed yields and days from flowering to maturity. 2. Correlations between seed yields and some morphological characteristics on the sowing date bases are shown in Table 2. From this table, it was also observed that there were some close relationships between seed yields and branch number for plant, stem diameter, plant weight, pod number per plant, and grain number per plant, but there was no clear relationship between seed yields and stem length, and between seed yields and 100 grain weight, on every sowing plot. 3. Relations between varietal yields and the sowing dates are shown in Table 3. Our leading varieties such as Ulsan, Sangdoo, Changdan Backmok, Iksan, Haman, Barchongdeo, and Anion Daerip, which belong to the maturity groups of IV, V, and VI, have been significantly high in yield at each sowing date plot, but the extreme early varieties, that frequently are damaged by insects, moisture and diseases, and the extreme late varieties, that frequently are caught by frost suffering reduced yield, are showed a lower yield than the others. However, extreme early varieties, for instance, Black Hawk, an American variety, and Chung Buk Baek, a Korean early variety, showed high productivity on the late sowing, June and July sowing plots, and Do san No. 6, which is late Japanese variety, showed a high yield on the extreme early sowing, i.e. April sowing plots. 4. Relations between seed yields and the sowing dates on the varietal bases are shown in Table 4. It was observed that, the early varieties did not differ much in yields at the various sowing dates while the yields of late varieties decreased progressively with subsequent dates. However, the extreme late varieties, such as Tamanishiki, that frequently are caught by frost suffering reduced yield, may be difficult to harvest at this location. The results in these experiments showed that in most cases maximum yields were obtained when leading varieties, which are medium or late varieties, were shown in Mid-May, and progressively lower yields were produced from June and July sowings. On the other hand, the late sowings of the early varieties, such as Black Hawk and Chung Buk Baek, in these experiments showed favorable yields compared with the others. From these results, we can predict that our local medium or late varieties produce higher yields at this location than was produced by early varieties in most of the sowing dates, especially the May sowing, and early varieties such as Black Hawk and Chung Buk Baek should be used in the late sowing, June sowing time.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.2
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• pp.27-29
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• 1964

Experiments were carried out to clarify the relationships between seed yields and some ecological characteristics, seed yields and some morphological characteristics, and the relationships among the varietal yields on the several sowing plots when grown under different climatic conditions. Twenty-four soybean varieties were used as the material, selected at random from 138 varieties which were cultivated the year before. These varieties were grown in the Experimental Farm, Chinju Agricultural College, Kyung Sang Namdo, Korea, and seed sowing was conducted at 5 times, from April to July, in 1962 and 1963. The results obtained are summarized as follows: 1. Correlations between seed yields and some ecological characteristics on the sowing date bases are shown in Table 1. Among some ecological characteristics, it was observed that there wert close relationships between seed yields and days to flowering, and between seed yields and the total growing length, except on the late sowing, i.e. July sowing plots, However, there was no clear correlation between seed yields and durations of flowering, and between seed yields and days from flowering to maturity. 2. Correlations between seed yields and some morphological characteristics on the sowing date bases are shown in Table 2. From this table, it was also observed that there were some close relationships between seed yields and branch number for plant, stem diameter, plant weight, pod number per plant, and grain number per plant, but there was no clear relationship between seed yields and stem length, and between seed yields and 100 grain weight, on every sowing plot. 3. Relations between varietal yields and the sowing dates are shown in Table 3. Our leading varieties such as Ulsan, Sangdoo, Changdan Backmok, Iksan, Haman, Barchongdeo, and Anion Daerip, which belong to the maturity groups of IV, V, and VI, have been significantly high in yield at each sowing date plot, but the extreme early varieties, that frequently are damaged by insects, moisture and diseases, and the extreme late varieties, that frequently are caught by frost suffering reduced yield, are showed a lower yield than the others. However, extreme early varieties, for instance, Black Hawk, an American variety, and Chung Buk Baek, a Korean early variety, showed high productivity on the late sowing, June and July sowing plots, and Do san No. 6, which is late Japanese variety, showed a high yield on the extreme early sowing, i.e. April sowing plots. 4. Relations between seed yields and the sowing dates on the varietal bases are shown in Table 4. It was observed that, the early varieties did not differ much in yields at the various sowing dates while the yields of late varieties decreased progressively with subsequent dates. However, the extreme late varieties, such as Tamanishiki, that frequently are caught by frost suffering reduced yield, may be difficult to harvest at this location. The results in these experiments showed that in most cases maximum yields were obtained when leading varieties, which are medium or late varieties, were shown in Mid-May, and progressively lower yields were produced from June and July sowings. On the other hand, the late sowings of the early varieties, such as Black Hawk and Chung Buk Baek, in these experiments showed favorable yields compared with the others. From these results, we can predict that our local medium or late varieties produce higher yields at this location than was produced by early varieties in most of the sowing dates, especially the May sowing, and early varieties such as Black Hawk and Chung Buk Baek should be used in the late sowing, June sowing time.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.2
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• pp.136-143
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• 2015

Gotjawal areas have the unique ecosystem and we need to approach as the inhabit of animals to conserve Gotjawal. This study was conducted in Hangyeong-myeon Cheongsu-ri located in the western part of Jeju Island belonging to Hangyeong Andeok Gotjawal Zone and Jocheon-eup Seonheul-ri located in the eastern part of Jeju Island belonging to Jocheon Hamdeok Gotjawal Zone. Survey on advent of the birds was done twice a month from February 2013 to December 2014. A total of 66 species and 4,140 individuals in two Gotjawals were observed during the survey period. In Seonheul Gotjawal area, 53 species and 1,907 individuals were observed while it was 49 species and 2,233 individuals in Cheongsu Gotjawal area. The number of species between two Gotjawal areas was not significantly different, but the number of individuals between two Gotjawal areas was significantly different. Thirty-six species were found in both Gotjawal areas as common species and the index of similarity was 0.7. A total of 23 species were classified as the residents, 15 species as the winter visitors, 16 species as the passage migrants, 11 species as the summer visitors, and 2 species as the vagrant. Twelve species as legally protected birds including the natural monument and the endangered species were found and 8 species were found in Seonheul Gotjawal area while it was 10 species in Cheongsu Gotjawal area. The species that directly using a wetland or food resources related to water were 12 in the Seonheul and 6 species were observed in the Cheongsu Gotjawal area, but there is no significant difference between two Gotjawal areas. However, the number of individuals in Seonheul Gotjawal area was significantly higher than in that of in Cheongsu Gotjawal area. We need to research the wetlands and micro climatic condition existing in Gotjawal forests to find the cause of difference of two areas and this difference must be considered as an important indicator for the protection of Gotjawal forests.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.1
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• pp.2177-2190
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• 1971

This experiment was made to determienthe effect of various soil moisture contents in simulated drought conditions on different stages of rice growth. The drought conditions were developed at such three rice-growing stages as transplanting, immediately after transplanting and young ear forming. Three different lengths of drought periods, which are ten days, twenty days and thirty days, were applied for each growing stage of rice. The rice variety used this experiment is Nong-rim 29. This experiment was conducted at the university farm of the Kon-Kuk University during the period of $1968{\sim}1970$. Three reprications for each of 12 treatments and split plot design were employed in this study. Bottomless wood square boxes, $1^m{\times}1^m{\times}1^m$, were burried in the test plot and box top was covered with poloyethylene sheets to avoid natural rainfall drops. Standard plots were irrigated continuously with a water depth of 40mm/day and those of drought treatments were irrigated continuously up to the beginning of the planned drought period, and they were irrigated again with a depth of 40mm/day up to the maturing stage of rice. Other methods for rice raising followed those methods developed by the Field Crops Experiment Station of the Office of Rural Development. During this experiments, climatic conditions in regard to rainfalls, sunshine hours, and temperatures were observed. According to this observation, those values measured deviate slightly from the annual means. However the growing condition of rice plants were normal. The pH value of irritation water is nearly neutral, and soils in the test plots are relatively fertile, being similar to ordinary paddy soils. Analysis of variances for number of stalks, plan-height, ear sprouting date, length of stalks, ear length, number of ears per plant, fertility, grain weitght, weight of plant, and yield were carried out. The variances for plant height, ear sprouting date, length of stalk ear length, and yield has statistical significance under drought treatments applied at three different growing stages. The variance showing the effect of lengths of drought period is highly significant for all the treatments studied except that of grain weight. The interaction between drought periods and drought treatments at different growing stages is significant for plant height, stalk length, ear length, number of ears, fertility and yield, these results indicated that droughts at different growing stages have influence on plant height, ear length, yield, and length of drought period also has strong influence on all factors studied except grain weight. The combination of drought treatments at different rice growing stages and lengths of drought periods has different effects on various agronomic characteristics, including yield. Plant height under drought treatment practiced at transplanting stage is the lowest, and drought treatment applied immediately after transplanting resulted in the least number of stalks. The effect of different lengths of drought periods on plant height and number of stalks depends signis ficantly on increasing days of drought. Ear sprouting date tends to be delayed for one or two days undedrought treatments at transplanting period and with increasing days of drought. Better yield is secured in drought treatment applied immediately after transplanting. Adverse effect war observed when drought treatment was applied at ear forming period. These effects may be attributed to the alternation of irrigation and drought causing vigorous root activity. In general, yield linearly decreases as the length of the drought period increases. The results obtained in this study demonstrate that, in order to mimimize damage due to drought, and, to save irrigation water, paddy fields, immediately after transplanting, may be not irrigated, since there is sufficient moisture in the soil, and that sufficient irrigation water should be applied again in the ear forming stage of rice plant.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.188-202
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• 1997

The seasonal variability of the sea surface winds over the last Sea of Korea (Japan Sea) is investigated by means of empirical orthogonal function (EOF) analysis. The combined representation of fields of three climatic variables by empirical orthogonal functions is discussed. The eigenvectors are derived from daily sea level pressure, wind speed and 10-day mean sea surface temperature (SST) during 15 years $(1978\~1992)$. The spatial patterns of the mean pressure are characterized by the high pressure in the western part and the low pressure in the eastern part. The spatial distribution of the standard deviation (SD) of pressure are characterized by max SD of 6.6 mb near the Vladivostok, and minima along the coast of the Japan. In Vladivostok, the maxima of SD of SST and south-north wind (WV) were also occurred. The representation of fields of individual meteorological variables by EOF shows that the first mode of the west-east wind (WU) explain over $47.3\%$ of the variance and the second mode of WU represents $30\%$. Especially, the first mode of the WV explain $70.9\%$ of the variance and their time series coefficients show 1-cpy, 0.5-cpy frequency spectrum. The spatial distribution of the first mode eigenvectors of SST are characterized by maximum near Vladivostok. The combined representation of fields of several variables (pressure, wind, SST) reveals that the first mode magnitudes of the variance of the combined eigenvectors (WU-PR) are increased. By means of this result, the 1-year peak and the 6-months peak are remarkable. In the three combined patterns (wind, pressure, SST), the second mode of the eigenvector (wind) is affected by the SST. Their time coefficients of the first mode show noticeable 1-year peak. The spectral analysis of the second mode shows broad seasonal signal with the period of 4-months and a significant peak of variability at 3-month period.

• The Korean Journal of Quaternary Research
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• v.2 no.1
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• pp.25-50
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• 1988

The survival of rich evidence of palaeolithic occupation found in the Imjin-Hant'an River basin was possible due to many fortuitous geological conditions provided there. Formation of the basalt plain in a narrow valley system which developed during the late Mesozoic insured the appearance of a basin of sedimentation in which archaeological sites would be preserved with relatively minor post-depositional disturbance. Geomagnetic and K-Ar dating indicates that lava flows occurred during the Brunes Normal Epoch. During and after the process of basin sedimentation, erosion of the plain was confined to the major channel of the present river system which developed along the structural joints formed by the lava flow. Due to characteristic columnar structure and platy cleavage of the basalt bedrock, erosion of the basalt bedrock occurred mainly in vertical direction, developing deep but narrow entrenched valleys cut into the bedrock. Consequently, the large portion of the site area remained intact. Cultural deposits formed on top of the basalt plain were left unmodified by later fluvial disturbances due to changes in the Hant'an River base-level, since they were formed about 20 to 40m above the modern floodplain. Sedimentological evidence of cultural deposits and palynological analysis of lacustrine bed formed in the tributary basin of the Hant'an River indicate that hominid occupation occurred in this basin under rapidly deteriorating climatic conditions. From three thermoluminescence dates, the timing of hominid occupation as represented by 'Acheulian-like' bifaces apparently occur sometime during 45,000 BP. Thus, deposition of cultural layers in this basin approximately coincides with the beginning of the second stadial of the final glacial, during which the Korean Peninsula must have had provided a sanctuary for prolonged human occupation.

• The Korean Journal of Mycology
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• v.45 no.4
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• pp.270-283
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• 2017

In a survey on higher fungi from 2004 to 2011, and also in 2013, in Naejangsan National Park, a total of 2 divisions, 7 classes, 21 orders, 74 families, 229 genera, and 521 species were observed. Dominant species belonged to the families Boletaceae and Russulaceae (44 species), Agaricaceae (35 species), Polyporaceae (29 species), and Amanitaceae (27 species). For the habitat environment, 21 families, 44 genera, and 192 species (36.9%) (63 species of poisonous mushroom, 79 species of edible and medicinal mushroom, and 43 species of unknown edible & poisonous mushroom) of ectomycorrhizal mushrooms were found; 41 families, 118 genera, and 199 species (38.2%) (14 species of poisonous mushroom, 85 species of edible & medicinal mushroom, and 90 species of unknown edible and poisonous mushroom) of litter decomposing and wood rotting fungi were found, and 29 families, 66 genera, and 121 species (23.2%) (8 species of poisonous mushroom, 54 species of edible and medicinal mushroom, and 47 species of unknown edible & poisonous mushroom) of grounding fungi were found, and 9 species were the other habitat. In terms of seasonality, most of the higher fungi were found in July, August, and September. In terms of altitude, the most species were observed at 200~299 m, and populations dropped by a significant level at an altitude of 700 m or higher. It seemed that the most diversified higher fungi occurred at climate conditions with a mean air temperature of $25.0{\sim}28.9^{\circ}C$, a maximum air temperature of $30.0{\sim}33.9^{\circ}C$, a minimum air temperature of $21.0{\sim}24.9^{\circ}C$, a relative humidity of 73.0~79.9%, and over 400.0 mm of rainfall.

• Korean Journal of Weed Science
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• v.12 no.3
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• pp.261-270
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• 1992

Many herbicides that are applied at the soil before weed emergence inhibit plant growth soon after weed germination occurs. Plant growth has been known as an irreversible increase in size as a result of the processes of cell divison and cell enlargement. Herbicides can influence primary growth in which most new plant tissues emerges from meristmatic region by affecting either or both of these processes. Herbicides which have sites of action during interphase($G_1$, S, $G_2$) of cell cycle and cause a subsequent reduction in the observed frequency of mitotic figures can be classified as an inhibitor of mitotic entry. Those herbicides that affect the mitotic sequence(mitosis) by influencing the development of the spindle apparatus or by influencing new cell plate formation should be classified as causing disruption of the mitotic sequence. Sulfonylureas, imidazolinones, chloroacetamides and some others inhibit plant growth by inhibiting the entry of cell into mitosis. The carbamate herbicides asulam, carbetamide, chlorpropham and propham etc. reported to disrupt the mitotic sequence, especially affecting on spindle function, and the dinitroaniline herbicides trifluralin, nitralin, pendimethalin, dinitramine and oryzalin etc. reported to disrupt the mitotic sequence, particularly causing disappearence of microtubles from treated cells due to inhibition of polymerization process. An inhibition of cell enlargement can be made by membrane demage, metabolic changes within cells, or changes in processes necessary for cell yielding. Several herbicides such as diallate, triallate, alachlor, metolachlor and EPTC etc. reported to inhibit cell enlargement, while 2, 4-D has been known to disrupt cell enlargement. One potential danger inherent in the use of soil acting herbicides is that build-up of residues could occur from year to year. In practice, the sort of build-up that would be disastrous is unikely to occur for substances applied at the correct soil concentration. Crop injury caused by soil applied herbicides can be minimized by (1) following the guidance of safe use of herbicides, particularly correct dose at correct time in right crop, (2) by use of safeners which protect crops against injury without protecting any weed ; interactions between herbicides and safeners(antagonists) at target sites do occur probably from the following mechanisms (1) competition for binding site, (2) circumvention of the target site, and (3) compensation of target site, and another mechanism of safener action can be explained by enhancement of glutathione and glutathione related enzyme activity as shown in the protection of rice from pretilachlor injury by safener fenclorim, (3) development of herbicide resistant crops ; development of herbicide-resistant weed biotypes can be explained by either gene pool theory or selection theory which are two most accepted explanations, and on this basis it is likely to develop herbicide-resistant crops of commercial use. Carry-over problems do occur following repeated use of the same herbicide in an extended period of monocropping, and by errors in initial application which lead to accidental and irregular overdosing, and by climatic influence on rates of loss. These problems are usually related to the marked sensitivity of the particular crops to the specific herbicide residues, e.g. wheat/pronamide, barley/napropamid, sugarbeet/ chlorsulfuron, quinclorac/tomato. Relatively-short-residual product, succeeding culture of insensitive crop to specific herbicide, and greater reliance on postemergence herbicide treatments should be alternatives for farmer practices to prevent these problems.

• Korean Journal of Environment and Ecology
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• v.34 no.4
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• pp.318-333
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• 2020

The Nakdong-Jeongmaek extends north and south from Taebaek-si of Gangwon-do to Busan metropolitan city and includes a wide range of forest zone from temperate to the warm-temperature forest. The purpose of this study was to analyze the vegetation structural characteristics of the Quercus mongolica-dominant community, which was distributed in the largest area in Baekdudaegan and Jeongmaek, by region and communities in the Nakdong-Jeongmaek. For the study, a representative 6 sites were selected: Baekbyeongsan, Chilbosan, Baegamsan, Unjusan, Goheonsan, and Gudeoksan. The survey of the 6 sites showed that the canopy had over 85% the importance percentage of Quercus mongolica. In the understory, Rhododendron schlippenbachii, Fraxinus sieboldiana, etc. were located and Fraxinus sieboldiana, Lespedeza maximowiczii, Tripterygium regelii and so on were found in the shrub. The importance percentage of 4 communities of Quercus mongolica, which were separated by TWINSPAN, in the canopy was more than 80%, and the dominant species in the understory and shrub were the same. Currently, Quercus mongolica has been identified as the understory following the canopy, and the Quercus mongolica-dominant community is expected to continue unless there are external factors. In the temperate forest regions in Korea, Quercus spp.and Carpinus laxiflora form the major forest physiognomy in the natural forest state. Based on these characteristics, the Quercus mongolica-dominant community on the ridge of the Nakdong-Jeongmaek is considered to have characteristics of temperate forests in Korea. The Quercus mongolica community is a representative cool-temperate deciduous forest and known as a climatic climax in the upper section of the mountains in the Korean Peninsula. Trees of the same species should be distributed at each layer to maintain the dominant species' status in the canopy's climax forest. Therefore, the Quercus mongolica community is considered the climax forest in the ridge of the Nakdong-Jeongmaek.