• KOREAN JOURNAL OF CROP SCIENCE
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• v.11
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• pp.81-97
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• 1972

Experiments and investigations were done basically and practically for the purpose of labor saving in paddy rice cultivation especially on Homizil i.e. hoeing and herbicide, 1969. 8 concrete tanks were established on the open base of Keon Kuk University for comparison of percolation, dissolved oxygen and yield test of rice in the paddy plot of tank. The dimension of the bottom of each tank is square meter. Each of the 4 of the 8 tanks is 21cm in height and each of the remaining 4 tanks is 36cm. Each tank has a system that comprises 2 sets of tubes, each of which has 20 holes of 5mm in diameter scattered every side and is covered with nylon cloth taking water in the tank. One set consists of 4 P.V.C tubes. The first set is situated 8cm below the top of the tank and the second set is located at bottom layer inside the tank. The 4 tubes of each set are combined together and led to the glass tube which protects from inside to outside. And this inside-outside glass tube is connected to the small rubber tube. Also a glass tube is set 4cm below the top of the tank. Paddy loam was filled on sand in each of the tanks in the soil depth of either 15cm or 30cm. The depth of sand was 5cm in the soil depth of 15cm and 10cm in the soil depth of 30cm. (Fig. 1, 2 and 3). The paddy rice was grown in the tank. The percolation of water, the dissolved oxygen and the yield of rice were observed in the tank. And the dissolved oxygen was detected by Winkler method. A sandy paddy field of heavy percolation was selected at the field of the National Agricultural Material Inspection Center in Seoul. It was divided into 9 plots. These plots were given 3 treatments: (A) not hoeing, (B) hoeing one time and (C) hoeing two times. These treatments were replicated 3 times along the latin square design. The paddy rice was grown and sprayed with Stam F-34 in the all plots for the purpose of killing weeds before hoeing. The two types of paddy of field i.e. one for normal percolation and the other for ill drainage were selected at Iri Crop Experiment Station, Jeonla-Bukdo. Each field was divided into 24 plots for 8 treatments. They are: (A) not hoeing; (B) hoeing one time; (C) hoeing two times; (D) not hoeing but treating with herbicide, Pamcon; (E) hoeing one time and weeding two times also treating with herbicide, Pamcon; (F) hoeing two times and weeding one time a], o treating with herbicide, Pamcon; (G) hoeing two times and weeding two times also treating with herbicide, Pamcon, ; (H) usual manner. The labor hours and expenses needed for weeding in the paddy by hoeing were investigated in a farmer at Suwon and the price of herbicide and the yield of rice were taken out at Iri, Jeonla-Bukdo. The results obtained from the above experiments and investigations are as follows: 1. The relationship between percolation and dissolved oxygen shows that a very small amount of oxygen is detected in the soil water under 2cm below surface of earth in the paddy even when percolation is over 4.0cm per 24 hours (Tab. 1). 2. The relationship between percolation and yield of rice shows that the yield of rice increases in the percolation of 0cm and 1.5cm per 24 hours and decreases in the percolation of 2.5cm and 3.4cm in the plot of the 15cm ploughing depth and increases in the percolation of 1.4cm and 3.0cm and decreases in the percolation of 0cm and 4.0cm in the plot of 30cm ploughing depth (Tab. 1 and Fig. 5). 3. The yield of paddy weeded with Stam F-34 in the sandy field of heavy percolation in Seoul was 3.02 tons in the plot of not hoeing, 2.99 tons in hoeing one time and 3.05 tons in hoeing two times per hectare (Tab. 5). 4.1). 4. 1) The yield of rice per 10 ares in the field of normal percolation at Iri was 338kg in not hoeing, 379kg in hoeing one time, 383kg in hoeing two times, 413kg in spraying herbicide, Pamcon, and not hoeing, 433kg in spraying herbicide, Pamcon, and hoeing one time and weeding two times, 399kg in spraying herbicide, Pamcon, and hoeing two times and weeding one time, 420kg in spraying herbicide, Pamcon, and hoeing two times and weeding two times and 418kg in usual manner (Tab. 6-1). 2) The yield of rice per 10 ares in the field of ill drainage at Iri was 323kg in not hoeing, 363kg in hoeing one time, 342kg in hoeing two times, 388kg in spraying herbicide, Pamcon, and not hoeing, 425kg in spraying herbicide, Pamcon, and hoeing one time and weeding two times, 427kg in spraying herbicide, Pamcon, and hoeing two times and weeding one time, 449kg in spraying herbicide, Pamcon, and hoeing two times and weeding two times and 412kg in usual manner (Tab. 6-2). 5. 1) The labor hours for weeding by hoeing was 37.1 hours but 53.5 hours if hours for meal, smoking and so on are included, and the expenses including labor cost needed for weeding by hoeing in the paddy rice was 2, 346 Won per 10 ares at Suwon (Tab. 7). 2) The labor hours for weeding by spraying herbicide with hand sprayer in the paddy rice was about 5 hours per 10 ares at Suwon and the expenses for weeding by spraying herbicide in the paddy rice was 750 Won but 1130 Won if the loss by decrement of rice in the paddy field of ill drainage per 10 ares is calculated in estimation at Iri (Tab. 8). From these observations and investigations it is known that using of some kinds of herbicides Saves labor and expenses of weeding, almost without giving damages to the rice itself, in the field of normal or heavy percolation comparing usual manner of hoeing.

• Journal of Food Hygiene and Safety
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• v.14 no.4
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• pp.372-379
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• 1999

A bacteriological study of sea water and oyster in Tongyeong coastal area was conducted to evaluate sanitary conditions of the bay and compliance of waters with the recommended bacteriological criteria fur the designated area of shellfish cultivation. The Samples were collected at 5 zone, 34 sampling stations(Fig. 1) established once a month from September 1997 to August 1998. During the study period, temperature ranged from 6.9 to 23.6$^{\circ}C$, transparency ranged from 2.6 to 6.2 m, chemical oxygen demand ranged from 1.35 to 1.82 mg/ι, dissolved oxy-gen ranged from 5.0 to 9.9 mg/ι, dissolved nitrogen ranged from 1.60 to 8.17 $\mu\textrm{g}$-at/ι, phosphate ranged from 0.14 to 1.21 $\mu\textrm{g}$-at/ι, Chlorophyll-a ranged from 2.03 to 69.9 mg/㎥, respectively. The coliform group and fecal coliform MPN's of sea water were ranged from <3.0~1,600 and <3.0~540, respectively. The coliform group and fecal coliform MPN's of oysters were ranged from <18~16,000 and <18~2,200, respectively. The viable cell counts in oyster ranged from $1.5\times$10$^2$to 8.2$\times$10$^3$. The coliform stoup, fecal coliform, classification of coliform group with IMViC reactions and pathogenic vibrios were analyzed. 437 strains that were obtained from Tongyeoung coastal area seawater samples represented E. coli group 47.5%, C. freundii group 14.8%, K. aerogenes 10.9%, unknown 26.8%, respectively. During the study period, infectious bacteria such as Vibrio ohoEerae, Salmonella sp. and Shigella sp. were not detected from the samples, but detection ratios of Vibrio parahaemolyticus and Vibrio vulnificus were 12~21% in summer months.

• Radiation Oncology Journal
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• v.17 no.4
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• pp.314-320
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• 1999

Purpose : Paclitaxel is a chemotherapeutic agent with potent microtubule stabilizing activity that arrests cells in $G_2$-M phase. Because $G_2$ and M are the most radiosensitive phase of the cell cycle, paclitaxel has potential role as a cell-cycle specific radiosensitizer. This study was peformed to see the effects of paclitaxel on the radiation-induced damage of gastric mucosa of the rat. Materials and Methods : The rats were divided into the three groups i.e., paclitaxel alone group, radiation alone group and, a combination of paclitaxel and radiation in combined group. A single intraperitoneal infusion of paclitaxel (10 mg/kg) was done in paclitaxel alone group. In radiation alone group, a single fraction of irradiation (8 Gy, x-ray) to the whole abdomen and, a combination of a single fraction of irradiation (8 Gy, x-ray) to the whole abdomen was given 24 hrs after paclitaxel infusion In combined group of paclitaxel and radiation. The incidence of mitosis and apoptosis as well as histologic changes of the gastric mucosa were evaluated at 6 hrs, 24 hrs, 3 days and 5 days after treatment. Results : The number of the mitosis was not increased by paclitaxel infusion. The incidence of the apoptosis was similar from 6 hrs to 3 days after paclitaxel infusion and was decreased at 5 days. Paclitaxel induced minimal glandular dilatation and cellular atypia of gastric mucosa at 24 hrs and 3 days. In irradiation group, the incidence of apoptosis was $6.0\%$ in 6 hrs and $1.25\%$ in 24 hrs after irradiation and minimal glandular dilatation and cellular atypia were noted throughout the experimental period. The incidence of apoptosis in the combined group of paclitaxel and irradiation ($4.5\%$) was significantly higher than irradiation alone group ($1.25\%$) at 3 days (p<0.05). Conclusion : Paclitaxel had no mitotic on mitotic arrest in gastric mucosa of the rat. Increased number of apoptosis in combined paclitaxel and irradiation group suggested the additive effects of paclitaxel on irradiation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.1
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• pp.85-92
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• 2008

An RIL population from a Shinpaldalkong2/GC83006 cross was employed to identify quantitative trait loci (QTL) associated with agronomic traits in soybean. The genetic map consisted of 127 loci which covered about 3,000cM and were assigned into 20 linkage groups. Phenotypic data were collected for the following traits; plant height, leaf area, flowering time, pubescence color, seed coat color and hilum color in 2005. Seed weight was evaluated using seeds collected in 2003 to 2005 at Suwon and in 2005 at Pyeongchang and Miryang sites. Three QTLs were associated with 100-seed weight in the combined analysis across three years. Among the three QTLs related to seed weight, all GC83006 alleles on LG O ($R^2\;=\;12.5$), LG A1 ($R^2\;=\;10.1$) and LG C2 ($R^2\;=\;11.5$) increased the seed weight. A QTL conditioning plant height was linked to markers including Satt134 (LG C2, $R^2\;=\;25.4$), and the GC83006 allele increased plant height at this QTL locus. For two QTLs related to leaf area, 1aM on LG M ($R^2\;=\;10.0$) and laL on LG L ($R^2\;=\;8.6$), the Shinpaldalkong2 alleles had positive effect to increase the leaf area. Satt134 on LG C2 ($R^2\;=\;41.0$) was associated with QTL for days to flowering. Satt134 (LG C2) showed a linkage to a gene for pubescence color. Satt363 (LG C2) and Satt354 (LG I) were linked to the hilum color gene, and Sat077 (LG D1a) was linked to the seed coat color. The QTL conditioning plant height was in the similar genomic location as the QTLs for days to flowering in this population, indicating pleiotropic effect of one gene or the tight linkage of several genes. These linked markers would be useful in marker assisted selection for these traits in a soybean breeding program.

• Korean Journal of Cognitive Science
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• v.27 no.4
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• pp.573-597
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• 2016

Recent fMRI and EEG research for neural representations of action concepts insist that processing of action concepts evoke the simulation of sensory-motor information. Moreover, there are several behavioral studies showing that understanding of action verbs or sentences describing actions interfere or facilitate current action performance. However, it is unclear that online interaction between processing of action concepts and current action is based on the simulation of sensory-motor information, or other neural mechanisms. The present research aims to explore the underlying neural mechanism that how the perception of action language influence the performance of current action using high-spacial temporal resolution EEG and multiple source analysis techniques. For this, participants were asked to perform a cued-motor reaction task in which button-pressing hand action and pedal-stepping foot action were required according to the color of the cue, and we presented auditorily action verbs describing the responding actions (i.e., /press/, /step/, /stop/) just before the color cue and examined the interaction effect from the semantic congruency between the action verbs and the current action. Behavioral results revealed consistently a facilitatory effect when action verbs and responding actions were semantically congruent in both button-pressing and pedal-stepping actions, and an inhibitory effect when semantically incongruent in the button-pressing action condition. In the results of EEG source waveform analysis, the semantic congruency effects between action verbs and the responding actions were observed in the Wernicke's area during the perception of action verbs, in the anterior cingulate gyrus and the supplementary motor area (SMA) at the time when the motor-cue was presented, and in the SMA and primary motor cortex (M1) during action execution stage. Based on the current findings, we argue that perceived action verbs evoke the facilitation/inhibition effect by influencing the expectation and preparation stage of following actions rather than the directly activating the particular motor cortex. Finally we discussed the implication on the neural representation of action concepts and methodological limitations of the current research.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.4
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• pp.205-210
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• 2006

Purpose: FDG uptake on positron omission tomography (PET) has been considered a prognostic indicator in non-small cell lung cancer (NSCLC). The aim of this study was to assess the clinical significance of maximum value of SUV (maxSUV) in recurrence prediction in patients with surgically resected NSCLC. Materials & methods: NSCLC patients (n=42, F:M =14:28, age $62.3{\pm}12.3$ y) who underwent curative resection after FDG-PET were enrolled. Twenty-nine patients had pathologic stage 1, and 13 had pathologic stage II. Thirty-one patients were additionally treated with adjuvant oral chemotherapy. MaxSUVs of primary tumors were analyzed for correlation with tumor recurrence and compared with pathologic or clinical prognostic indicators. The median follow-up duration was 16 mo (range, 3-26 mo). Results: Ten (23.8%) of the 42 patients experienced recurrence during a median follow-up of 7.5 mo (range, 3-13 mo). Univariate analysis revealed that disease-free survival (DFS) was significantly correlated with maxSUV (<7 vs. $\geq7$, p=0.006), tumor size (<3 cm vs. $\geq3$ cm, p=0.024), and tumor tell differentiation (well/moderate vs. poor, p=0.044). However, multivariate Cox proportional analysis identified maxSUV as the single determinant for DFS (p=0.014). Patients with a maxSUV of $\geq7$(n=10) had a significantly lower 1-year DFS rate (50.0%) than those with a maxSUV of <7 (n=32, 87.5%). Conclusion: MaxSUV is a significant independent predictor for recurrence in surgically resected NSCLC. FDG uptake can be added to other well-known factors in prognosis prediction of NSCLC.

• Development and Reproduction
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• v.5 no.1
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• pp.73-79
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• 2001

Recently many studies have reported that total and bioavailable androgens reduced in male and female athletes and that physical exercise reduces the body weight and increases the reproductive abnormalities such as oligomenorrhea, anovulation, inadequate luteal phase, and delayed puberty in women by the inhibition of the hypothalamic-pituitary-gonadal (HPG) axis . In addition, high mileage endurance 겨nning, psychological stress, and military endurance training in men also reduce the secretion of reproductive hormones. To investigate the efffcts of physical endurance exercise on the secretion of reproductive hormones in men, androgenic hormones from adrenal glands and testis were measured in serum by the conventional radioimmunoassays after long-term (more than3 months), short-term (1 week), and acute (1${sim}$2 hours) physical exercises. Androgenic hormones from adrenal glands and testis such as total testosterone (TT), free testosterone (fT), dehydroepiandrosterone (DHEA), and androstenedione (A) decreased after thesestrenuous endurance trainings, whereas ACTH, cortisol, and dehydroepiandrosterone sulfetes (DHEAS) increased. Conadotropins (LH and FSH) were not idluenced by the physical exercises. Based upon the present results, we assume that the decrease in adrenal and testicular androgens by physical endurance exercises might be associated with the reproductive abnormalities in athletes by unknown factor(s) in addition to the HPG axis disturbance.

• Journal of Animal Science and Technology
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• v.45 no.5
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• pp.703-710
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• 2003

The purpose of this study was to detect association between genetic variation and economic trait in the porcine heart type fatty acid-binding protein gene as a candidate gene for the traits related with growth and meat quality in pigs. The H-FABP is a 15-kDa protein expressed in several tissues with high demand for fat metabolism such as cardiac and skeletal muscle and lactating mammary gland. H-FABP is small intracellular protein involved in fatty acid transport from the plasma membrane to the site of $\beta$-oxidation and/or triacylglycerol or phospholipid synthesis. In this study, H-FABP PCR-RFLP was performed in F$_2$ population composed of 214 individuals from an intercross between Korean Native Boars and Landrace sows. PCR products from two primer sets within H-FABP gene were amplified in 850bp and 700bp. Digestion of PCR products with the restriction digestion enzymes HaeⅢ and HinfⅠ, revealed fragment length polymorphisms(RFLPs). The genotype frequencies from H-FABP/HaeⅢ was .29 for genotype DD, .53 for genotype Dd, and .15 for genotype dd, respectively. The genotype frequencies of HH, Hh, and hh from H-FABP/HinfⅠ was .38, .41 and .20, respectively, in the population. Relationships between their genotypes and economic traits were estimated. In H-FABP/HaeⅢ locus, there were specific genotypes(Dd and dd) associated with economic traits such as body weights at 3, 5, 12, and 30 week of age (p〈.05 to .001). The ‘d’ allele was associated with gaining of body weight. In H-FABP/HinfⅠ locus, Genotypes of HH and Hh associated with growth traits such as body weights at 5, 12, and 30 week of age (p〈.05 or p〈.001) and back fat thickness, body fat including abdominal and trimmed fat (p〈.001) and intramuscular fat(p〈.05) The ‘H’ allele was positively associated with gaining of body weight and fatness deposition. In conclusion, a significant association of the H-FABP gene from its genetic variation was found on body weight, intramuscular fat and backfat thickness.

• Journal of the Korean Wood Science and Technology
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• v.2 no.4
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• pp.4-14
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• 1974

The total forest land area in Korea accounts for some 67 percent of the nation's land total. Its productivity, however, is very low. Consequently, forest production accounts for only about 2 percent of the gross national product and a minor proportion of no more than about 5 percent versus primary industry. In this case, however, only the direct income from forestry is taken into account, making no reference to the forestry output induced by other industrial sectors. The value added Or the induced forestry output in manufacturing the primary wood products into higher quality products, makes a larger contribution to the economy than direct contribution. So, this author has tried to analyze the structure of forestry and compute the repercussion effect and the induced output of primary forest products when utilized by other industries for their raw materials, Hsing the input-output table and attached tables for 1963 and 1966 issued by the Bank of Korea. 1. Analysis of forestry structure A. Changes in total output Durng the nine-year period, 1961-1969, the real gross national product in Korea increased 2.1 times, while that of primary industries went up about 1. 4 times. Forestry which was valued at 9,380 million won in 1961, was picked up about 2. 1 times to 20, 120 million won in 1969. The rate of the forestry income in the GNP, accordingly, was no more than 1.5 percent both in 1961 and 1962, whereas its rate in primary industries increased 3.5 to 5.4 percent. Such increase in forestry income is attributable to increased forest production and rise in timber prices. The rate of forestry income, nonetheless, was on the decrease on a gradual basis. B. Changes in input coefficient The input coefficient which indicates the inputs of the forest products into other sectors were up in general in 1966 over 1963. It is noted that the input coefficient indicating the amount of forest products supplied to such industries closely related with forestry as lumber and plywood, and wood products and furniture, showed a downward trend for the period 1963-1966. On the other hand, the forest input into other sectors was generally on the increase. Meanwhile, the input coefficient representing the yolume of the forest products supplied to the forestry sector itself showed an upward tendency, which meant more and more decrease in input from other sectors. Generally speaking, in direct proportion to the higher input coefficient in any industrial sector, the reinput coefficient which denotes the use of its products by the same sector becomes higher and higher. C. Changes in ratio of intermediate input The intermediate input ratio showing the dependency on raw materials went up to 15.43 percent m 1966 from 11. 37 percent in 1963. The dependency of forestry on raw materials was no more than 15.43 percent, accounting for a high 83.57 percent of value added. If the intermediate input ratio increases in any given sector, the input coefficient which represents the fe-use of its products by the same sector becomes large. D. Changes in the ratio of intermediate demand The ratio of the intermediate demand represents the characteristics of the intermediary production in each industry, the intermediate demand ratio in forestry which accunted for 69.7 percent in 1963 went up to 75.2 percent in 1966. In other words, forestry is a remarkable industry in that there is characteristics of the intermediary production. E. Changes in import coefficient The import coefficient which denotes the relation between the production activities and imports, recorded at 4.4 percent in 1963, decreased to 2.4 percent in 1966. The ratio of import to total output is not so high. F. Changes in market composition of imported goods One of the major imported goods in the forestry sector is lumber. The import value increased by 60 percent to 667 million won in 1966 from 407 million won in 1963. The sales of imported forest products to two major outlets-lumber and plywood, and wood products and furniture-increased to 343 million won and 31 million won in 1966 from 240million won and 30 million won in 1963 respectively. On the other hand, imported goods valued at 66 million won were sold to the paper products sector in 1963; however, no supply to this sector was recorded in 1963. Besides these major markets, primary industries such as the fishery, coal and agriculture sectors purchase materials from forestry. 2. Analysis of repercussion effect on production The repercussion effect of final demand in any given sector upon the expansion of the production of other sectors was analyzed, using the inverse matrix coefficient tables attached to the the I.O. Table. A. Changes in intra-sector transaction value of inverse matrix coefficient. The intra-sector transaction value of an inverse matrix coefficient represents the extent of an induced increase in the production of self-support products of the same sector, when it is generated directly and indirectly by one unit of final demand in any given sector. The intra-sector transaction value of the forestry sector rose from 1.04 in 1963 to 1, 11 in 1966. It may well be said, therefore, that forestry induces much more self-supporting products in the production of one unit of final demand for forest products. B. Changes in column total of inverse matrix coefficient It should be noted that the column total indicates the degree of effect of the output of the corresponding and related sectors generated by one unit of final demand in each sector. No changes in the column total of the forestry sector were recorded between the 1963 and 1966 figures, both being the same 1. 19. C. Changes in difference between column total and intra-sector transaction amount. The difference between the column total and intra-sector transaction amount by sector reveals the extent of effect of output of related industrial sector induced indirectly by one unit of final demand in corresponding sector. This change in forestry dropped remarkable to 0.08 in 1966 from 0.15 in 1963. Accordingly, the effect of inducement of indirect output of other forestry-related sectors has decreased; this is a really natural phenomenon, as compared with an increasing input coefficient generated by the re-use of forest products by the forestry sector. 3. Induced output of forestry A. Forest products, wood in particular, are supplied to other industries as their raw materials, increasng their value added. In this connection the primary dependency rate on forestry for 1963 and 1966 was compared, i. e., an increase or decrease in each sector, from 7.71 percent in 1963 to 11.91 percent in 1966 in agriculture, 10.32 to 6.11 in fishery, 16.24 to 19.90 in mining, 0.76 to 0.70 in the manufacturing sector and 2.79 to 4.77 percent in the construction sector. Generally speaking, on the average the dependency on forestry during the period 1963-1966 increased from 5.92 percent to 8.03 percent. Accordingly, it may easily be known that the primary forestry output induced by primary and secondary industries increased from 16, 109 million won in 1963 to 48, 842 million won in 1966. B. The forest products are supplied to other industries as their raw materials. The products are processed further into higher quality products. thus indirectly increasing the value of the forest products. The ratio of the increased value added or the secondary dependency on forestry for 1963 and 1966 showed an increase or decrease, from 5.98 percent to 7.87 percent in agriculture, 9.06 to 5.74 in fishery, 13.56 to 15.81 in mining, 0.68 to 0.61 in the manufacturing sector and 2.71 to 4.54 in the construction sector. The average ratio in this connection increased from 4.69 percent to 5.60 percent. In the meantime, the secondary forestry output induced by primary and secondary industries rose from 12,779 million Wall in 1963 to 34,084 million won in 1966. C. The dependency of tertiary industries on forestry showed very minor ratios of 0.46 percent and 0.04 percent in 1963 and 1966 respectively. The forestry output induced by tertiary industry also decreased from 685 million won to 123 million won during the same period. D. Generally speaking, the ratio of dependency on forestry increased from 17.68 percent in 1963 to 24.28 percent in 1966 in primary industries, from 4.69 percent to 5.70 percent in secondary industries, while, as mentioned above, the ratio in the case of tertiary industry decreased from 0.46 to 0.04 percent during the period 1963-66. The mining industry reveals the heaviest rate of dependency on forestry with 29.80 percent in 1963 and 35.71 percent in 1966. As it result, the direct forestry income, valued at 8,172 million won in 1963, shot up to 22,724 million won in 1966. Its composition ratio lo the national income rose from 1.9 percent in 1963 to 2.3 per cent in 1966. If the induced outcome is taken into account, the total forestry production which was estimated at 37,744 million won in 1963 picked up to 105,773 million won in 1966, about 4.5 times its direct income. It is further noted that the ratio of the gross forestry product to the gross national product. rose significantly from 8.8 percent in 1963 to 10.7 percent in 1966. E. In computing the above mentioned ratio not taken into consideration were such intangible, indirect effects as the drought and flood prevention, check of soil run-off, watershed and land conservation, improvement of the people's recreational and emotional living, and maintenance and increase in the national health and sanitation. F. In conclusion, I would like to emphasize that the forestry sector exercices an important effect upon the national economy and that the effect of induced forestry output is greater than its direct income.

• Journal of Korean Society of Forest Science
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• v.66 no.1
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• pp.16-36
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• 1984

It is very important in forestry to study the shear strength of weathered granitic soil, because the soil covers 66% of our country, and because the majority of land slides have been occured in the soil. In general, the causes of land slide can be classified both the external and internal factors. The external factors are known as vegetations, geography and climate, but internal factors are known as engineering properties originated from parent rocks and weathering. Soil engineering properties are controlled by the skeleton structure, texture, consistency, cohesion, permeability, water content, mineral components, porosity and density etc. of soils. And the effects of these internal factors on sliding down summarize as resistance, shear strength, against silding of soil mass. Shear strength basically depends upon effective stress, kinds of soils, density (void ratio), water content, the structure and arrangement of soil particles, among the properties. But these elements of shear strength work not all alone, but together. The purpose of this thesis is to clarify the characteristics of shear strength and the related elements, such as water content ($w_o$), void ratio($e_o$), dry density (${\gamma}_d$) and specific gravity ($G_s$), and the interrelationship among related elements in order to decide the dominant element chiefly influencing on shear strength in natural/undisturbed state of weathered granitic soil, in addition to the characteristics of soil hardness of weathered granitic soil and root distribution of Pinus rigida Mill and Pinus rigida ${\times}$ taeda planted in erosion-controlled lands. For the characteristics of shear strength of weathered granitic soil and the related elements of shear strength, three sites were selected from Kwangju district. The outlines of sampling sites in the district were: average specific gravity, 2.63 ~ 2.79; average natural water content, 24.3 ~ 28.3%; average dry density, $1.31{\sim}1.43g/cm^3$, average void ratio, 0.93 ~ 1.001 ; cohesion, $ 0.2{\sim}0.75kg/cm^2$ ; angle of internal friction, $29^{\circ}{\sim}45^{\circ}$ ; soil texture, SL. The shear strength of the soil in different sites was measured by a direct shear apparatus (type B; shear box size, $62.5{\times}20mm$; ${\sigma}$, $1.434kg/cm^2$; speed, 1/100mm/min.). For the related element analyses, water content was moderated through a series of drainage experiments with 4 levels of drainage period, specific gravity was measured by KS F 308, analysis of particle size distribution, by KS F 2302 and soil samples were dried at $110{\pm}5^{\circ}C$ for more than 12 hours in dry oven. Soil hardness represents physical properties, such as particle size distribution, porosity, bulk density and water content of soil, and test of the hardness by soil hardness tester is the simplest approach and totally indicative method to grasp the mechanical properties of soil. It is important to understand the mechanical properties of soil as well as the chemical in order to realize the fundamental phenomena in the growth and the distribution of tree roots. The writer intended to study the correlation between the soil hardness and the distribution of tree roots of Pinus rigida Mill. planted in 1966 and Pinus rigida ${\times}$ taeda in 199 to 1960 in the denuded forest lands with and after several erosion control works. The soil texture of the sites investigated was SL originated from weathered granitic soil. The former is situated at Py$\ddot{o}$ngchangri, Ky$\ddot{o}$m-my$\ddot{o}$n, Kogs$\ddot{o}$ng-gun, Ch$\ddot{o}$llanam-do (3.63 ha; slope, $17^{\circ}{\sim}41^{\circ}$ soil depth, thin or medium; humidity, dry or optimum; height, 5.66/3.73 ~ 7.63 m; D.B.H., 9.7/8.00 ~ 12.00 cm) and the Latter at changun-long Kwangju-shi (3.50 ha; slope, $12^{\circ}{\sim}23^{\circ}$; soil depth, thin; humidity, dry; height, 10.47/7.3 ~ 12.79 m; D.B.H., 16.94/14.3 ~ 19.4 cm).The sampling areas were 24quadrats ($10m{\times}10m$) in the former area and 12 in the latter expanding from summit to foot. Each sampling trees for hardness test and investigation of root distribution were selected by purposive selection and soil profiles of these trees were made at the downward distance of 50 cm from the trees, at each quadrat. Soil layers of the profile were separated by the distance of 10 cm from the surface (layer I, II, ... ...). Soil hardness was measured with Yamanaka soil hardness tester and indicated as indicated soil hardness at the different soil layers. The distribution of tree root number per unit area in different soil depth was investigated, and the relationship between the soil hardness and the number of tree roots was discussed. The results obtained from the experiments are summarized as follows. 1. Analyses of simple relationship between shear strength and elements of shear strength, water content ($w_o$), void ratio ($e_o$), dry density (${\gamma}_d$) and specific gravity ($G_s$). 1) Negative correlation coefficients were recognized between shear strength and water content. and shear strength and void ratio. 2) Positive correlation coefficients were recognized between shear strength and dry density. 3) The correlation coefficients between shear strength and specific gravity were not significant. 2. Analyses of partial and multiple correlation coefficients between shear strength and the related elements: 1) From the analyses of the partial correlation coefficients among water content ($x_1$), void ratio ($x_2$), and dry density ($x_3$), the direct effect of the water content on shear strength was the highest, and effect on shear strength was in order of void ratio and dry density. Similar trend was recognized from the results of multiple correlation coefficient analyses. 2) Multiple linear regression equations derived from two independent variables, water content ($x_1$ and dry density ($x_2$) were found to be ineffective in estimating shear strength ($\hat{Y}$). However, the simple linear regression equations with an independent variable, water content (x) were highly efficient to estimate shear strength ($\hat{Y}$) with relatively high fitness. 3. A relationship between soil hardness and the distribution of root number: 1) The soil hardness increased proportionally to the soil depth. Negative correlation coefficients were recognized between indicated soil hardness and the number of tree roots in both plantations. 2) The majority of tree roots of Pinus rigida Mill and Pinus rigida ${\times}$ taeda planted in erosion-controlled lands distributed at 20 cm deep from the surface. 3) Simple linear regression equations were derived from indicated hardness (x) and the number of tree roots (Y) to estimate root numbers in both plantations.