• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.147-157
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• 1973

I. The effect of excessive soil moisture(at the time of germination) on germination of barley and crop damage of herbicides was investigated. Machete(Butachlor) and TOK(Nitrofen) were treated, respectively, at the rate of 150g ai/10a on each pot whose different soil moisture content was controlled by suppling 30, 40, 50 and 60ml of water per 100gr of air-dried soil, respectively. The results are summarized as follows: 1. Excessive soil moisture beyond field moisture capacity caused great inhibition, from 20 to 100%, of the germination of barley even at untreated pots(check pots). Also, further development of root and growth of barley were greatly inhibited even though the seeds germinated. 2. The same tendency in inhibition of germination and growth as at untreated pots was observed at treated pots, too. As a whole, however, the damage were heavier at treated pots. II. Wanju naked spring barley was seeded on four different soils and covered with soil to a depth of 1 em, and then Machete, TOK, Saturn and HE-314 were treated at the rate of 180, 150 and 200, 150, and 250g ai/10a, respectively, and the effect of soil texture on crop damage of the herbicides was investigated. The results are summarized as follows: 1. Machete(emulsion and granule, at 180g ai/10a) The degree of crop damage was quite different from one soil texture to another: while almost no crop damage was observed on a clay loam soil regardless of the type of formulation, the damage became heavier as the soil texture became sandier as sandy clay loam, volcanic ash loam and sandy loam, and great inhibition of growth was observed on sandy loam soil. In general heavier damage was caused by the application of emulsion than by granular formulation. 2. TOK(Wettable powder, at 150, 250g ai/l0a) Almost the same tendency as in the application of Machete was observed, and the damage became heavier as the application rate increased. 3. Saturn(at l50g ai/l0a) No great difference in crop damage among soil textures was observed. 4. HE-3l4(at 250g ai/l0a) Almost no difference in crop damage among soil textures was observed at this rate of 250g ai/l0a. III. To study a difference of crop damage on soil covering depth(4 levels), 9 herbicides(TOK, MO, HE-3l4, Machete, Saturn, Simetryne, Simazine, Gesaran, Lorox) were treated on the pots with two different soils, and the effect of soil covering depth on crop damage of the herbicides was investigated. The results obtained in this experiment are summarized as follows: Light Clay Soil 1. The growth of barley in relation to depth of soil covering at check pots followed the order vigorous to weak; lcm>1.5cm>0.5cm>0cm. And in case of 0 and 0.5cm covering the growth of barley was very poor. 2. The damage at 0 and 0.5cm covering at treated pots was very severe, but Saturn, Machete, MO and TOK at 100 to l50g ai/l0a, respectively and He-3l4 at 250 to 375g ai/l0a were relatively safe to barley at the depths of lcm and above. 3. Simazine, Lorox and Simetryne caused slight damage even at 1.5cm covering. Sandy Loam Soil The growth of barley in relation to depth of soil covering at untreated pots followed the order, from vigorous to weak; 1.5cm 0.5cm 3cm 5cm. While MO was safe to barley at 1.5cm covering, for other chemicals more than 3cm covering was require for safe use. Machete and Saturn at 100g ai/l0a, and HE-3l4 at 250g ai/l0a was relatively safe at more than 3cm covering. Simazine, Lorox, Simetryne and Gesaran were unsafe on sandy soil regardless of covering depth.

• Korean Journal of Veterinary Research
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• v.4 no.1
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• pp.35-42
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• 1964

1). An nanlysis was made of 3,500 postmortem diagnoses for the three years 1961 through 1963 to determine whether there was any actual incidence of avian visceral lymphomntosis in the field. Chickens autopsied, which showed gross alterations were 7.6 percent or 266 cases. The diminished incidence of the disease in second and third years seemed due to decreased total numbers of chicken flocks year by year for the reason of difficult feed supply. 2). Because chickens autopsied in this study were not clearly known of their breeds and lines, no distinct data on the incidence in various breeds were made. Some exact breeds were in too small numbers to have any statistical significance. Inconceivably, no other types of avian leukosis than visceral lymphomatosis had been observed in any appreciable number in this analysis. 3). Pathologic analysis for affected organs was made grossly and microscopically. In the gross pictures, liver, spleen, kidney, ovary, and in some case, intestine principally showed lesions, but its manifestation was variable in different organs. In such organs, livers were affected more frequently, and spleens followed next. The organs were classified and arranged according to the gross alterations, and among their distribution one-half of livers were in diffuse variety; one-fourths in nodular; about one-sevenths in mixed; and granular variety followed next. In the spleen samples, two-thirds were in diffuse variety; one-fourths in nodular; and follicular only in three cases. Ovaries almost showed follicular lesions, the diffused were less than one-fifths of total specimens. Kidneys were occurred almost in diffuse variety. And intestine showed only nodular tomors. Microscopically, 42 cases of visceral lymphomatosis composed of 24 livers, 10 spleens, 3 kidneys, 3 intestines and 2 ovaries were examined. The tumor cells were lymphoid cells showing various component in size, shape and stainability. Mitotic figures were usually present. The proportion of the component cells were various in all cases and there were variations in the distribution of the tumor cells. The types of distribution were classified according to the standard proposed by Horiuchi as nodular, infiltrative and diffuse proliferation. In cases of visceral lymphomatosis of the livers and the spleens the types of infiltrative, nodular and diffuse proliferation could be classified. In the cases of the kidneys the types of diffuse and nodular proliferation were observed. In the cases of the intestines and the ovaries the types of infiltrative and diffuse proliferation were observed respectively.

• Journal of Sericultural and Entomological Science
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• v.25 no.1
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• pp.34-43
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• 1983

These studies have been carried out to find better locations for sericultural service regardless of the international silk market fluctuation in Korea. In order to acieve the purpose, various investigations and analyses have been carried out for more than four hundred sericultural communities to find out the main factors which caused to decrease in cocoon production in spite of a gloomy past silk market. Now, we believe that we have set up some fundamental guide lines in developing sound serviceable sericultural communities in Korea in case the government accepts the written advices, and the results obtained are as follows: 1. The Korean sericulture has been very prosperous from the 60's to the 70's. In 1976 the cocoon production was at its peak, reaching 41,704M/T from which its decline took place with annual averages of 18.5% for total cocoon production and 16.4% for mulberry field. These figures represent a quantitative decrease to one-third of the total amount in 1976. Since then, the Korean sericulture had continuously suffered from a shortage of raw silk resulting in a slow development of sericulture. At present, a steady development through all possible measures is great importance. 2. The downfall of the korean sericulture resulted from two factors of such as the external, which led to the decline in the price of raw silk at the international market and restrain of import and, the internal, resulting in the little increase of cocoon price and a comparatively lower benefits from the sericulture than from other cash crops. 3. The already established sericultural zone collapsed and then reorganized with the outstanding regional specialization so the decline in total cocoon production in the country. Based on the agricultural regions, 1980 cocoon production was very stable in the mountaineaus area of the east-south which used with intercropping. In this area there was small decline of 33% compare with that of the 1979, and with 70% decline in the dry field farming area of Kangwon Do. In an administrative districtwise, six counties beginning with Sanchnung county of Kyungsang Nam Do, showed less than 20% decline of cocoon production, sixteen counties beginning with Samchuck county of Kangwon Do marked above 80% decrease of cocoon production. In the smaller unit area-wise, there was a big difference among them. twenty-five myons rather increased and a hundrd fourty-three myons decreased above 80% of it. 4. The cocoon production was positively correlated with the decreasing percentage of cocoon production per household. It was also affected by the ratio of the mulberry field area to the total cultivated area per household and cocoon productivity per 10a. 5. Four hundred sixty-four villages in the seventeen counties were surveyed on the basis of farm management and techniques concerned ('80/'79), and then the results were evaluated by using of computer. These results are summarized as foolows: (1) Cocoon production per household There was no difference among the agricultural regions in cocoon production. The cocoon production per household in the comparatively stable villages increased from 100.8kg in 1979 to 122kg in 1981. Cocoon yield in the stable villages decreased by 20% of '81/'79. The cocoon production per house hold in while that of the unstable villages decreased by more than 40% from 102.9kg in 1979 to 82kg in 1981. (2) Cocoon yield per 10a mulberry field The cocoon yield per 10a was higher in the plain area than in the mountaineous area. The stable villages had an average of 73.4kg cocoon yield/10a while the unstabe ones had only an average of 55kg. (3) Adoption the mulberry branch rearing method The branch rearing method was more popular in the plain area than in the mountainous area. In the stable vilages adopted 24.2% in spring and 16.7% in autumn of 1979. In 1981 it shwed increases of 34.3% and 10.1% in the two seasons respectivly. However, the unstable villages showed 13.3% and 126% in both seasons, respectively. (4) The patterns of the combined management system in the sericultural farming The popular management system in the sericultural from was combined with rice and other cash crops, showing 55% of the total households surveyed. Fourteen percent of the households combined the management system with rice and other cash crops and 14% of the households combined with rice only. The villages wich earned less than 20% of the total income from the sericulture reached 81% of the total houscholds indicating that they were still far beyond a complete combination system. (5) Damage by agricultural chemicals The damage caused by agricultural chemicals was mainly due to the protection of rice against insectpests and diseases in the plain areas and took place mostly in the autumn season. The chemicals applied was 65% of Iiquid and 35% of powder forms and 35% of damage was from granulat form of the chemicals. The use of the granular chemicals was low because of high cost.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.3
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• pp.103-134
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• 1977

The physiological and biochemical role of potassium for upland crops according to recent research reports and the nutritional status of potassium in Korea were reviewed. Since physical and chemical characteristics of potassium ion are different from those of sodium, potassium can not completely be replaced by sodium and replacement must be limited to minimum possible functional area. Specific roles of potassium seem to keep fine structure of biological membranes such as thylacoid membrane of chloroplast in the most efficient form and to be allosteric effector and conformation controller of various enzymes principally in carbohydrate and protein metabolism. Potassium is essential to improve the efficiency of phoro- and oxidative- phosphorylation and involve deeply in all energy required metabolisms especially synthesis of organic matter and their translocation. Potassium has many important, physiological functions such as maintenance of osmotic pressure and optimum hydration of cell colloids, consequently uptake and translocation of water resulting in higher water use efficiency and of better subcellular environment for various physiological and biochemical activities. Potassium affects uptake and translocation of mineral nutrients and quality of products. potassium itself in products may become a quality criteria due to potassium essentiality for human beings. Potassium uptake is greatly decreased by low temperature and controlled by unknown feed back mechanism of potassium in plants. Thus the luxury absorption should be reconsidered. Total potassium content of upland soil in Korea is about 3% but the exchangeable one is about 0.3 me/100g soil. All upland crops require much potassium probably due to freezing and cold weather and also due to wet damage and drought caused by uneven rainfall pattern. In barley, potassium should be high at just before freezing and just after thawing and move into grain from heading for higher yield. Use efficiency of potassium was 27% for barley and 58% in old uplands, 46% in newly opened hilly lands for soybean. Soybean plant showed potassium deficiency symptom in various fields especially in newly opened hilly lands. Potassium criteria for normal growth appear 2% $K_2O$ and 1.0 K/(Ca+Mg) (content ratio) at flower bud initiation stage for soybean. Potassium requirement in plant was high in carrot, egg plant, chinese cabbage, red pepper, raddish and tomato. Potassium content in leaves was significantly correlated with yield in chinese cabbage. Sweet potato. greatly absorbed potassium subsequently affected potassium nutrition of the following crop. In the case of potassium deficiency, root showed the greatest difference in potassium content from that of normal indicating that deficiency damages root first. Potatoes and corn showed much higher potassium content in comparison with calcium and magnesium. Forage crops from ranges showed relatively high potassium content which was significantly and positively correlated with nitrogen, phosphorus and calcium content. Percentage of orchards (apple, pear, peach, grape, and orange) insufficient in potassium ranged from 16 to 25. The leaves and soils from the good apple and pear orchards showed higher potassium content than those from the poor ones. Critical ratio of $K_2O/(CaO+MgO)$ in mulberry leaves to escape from winter death of branch tip was 0.95. In the multiple croping system, exchangeable potassium in soils after one crop was affected by the previous crops and potassium uptake seemed to be related with soil organic matter providing soil moisture and aeration. Thus, the long term and quantitative investigation of various forms of potassium including total one are needed in relation to soil, weather and croping system. Potassium uptake and efficiency may be increased by topdressing, deep placement, slow-releasing or granular fertilizer application with the consideration of rainfall pattern. In all researches for nutritional explanation including potassium of crop yield reasonable and practicable nutritional indices will most easily be obtained through multifactor analysis.