• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.2
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• pp.102-117
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• 2009

This study was carried out to investigate the extent to which benthic environment of Ulsan Bay was disturbed by organic materials and trace metals from the megacity and industrial complex. Field survey for benthic environment and macroinvertebrate community was seasonally conducted from February to November 2006 at nine stations covering the inside and outside of the bay. TOC was on average 1.7% while four (As, Cu, Pb, Zn) out of seven trace metals measured exceeded the Effects Range Low (ERL) in most of the stations. Total number of species sampled was 199 and mean density was 4,578 ind./$m^2$, both of which were greatly dominated by the polychaetes. Dominant species were Aphelochaeta monilaris (22.6%), Ruditapes philippinarum (17.1%), Magelona japonica (12.2%), Lumbrineris longifolia (9.9%) and their distribution was ruled by the difference in the benthic environmental condition of each station. From the multivariate analyses, four stational groups were identified: northern part of the bay, middle and lower part of the bay, the intersection of Taewha River and Gosa stream and outside of the bay. As a result, the community heterogeneity of inner bay was much more greater than that of outer bay. SIMPER analysis showed that four groups were represented by R. philippinarum-Capitella capitata, A. monilaris-Balanoglossus carnosus, Sinocorophium sinensis-Cyathura higoensis and M. japonica-Ampharete arctica, respectively. Spatio-temporal changes of macroinvertebrate communities in Ulsan Bay were closely related to those of depth, mean grain size and organic content, and Zn was also a meaningful factor in that context.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.4
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• pp.213-228
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• 2009

This study was conducted to investigate spatio-temporal changes in macrobenthic community structure and benthic environmental conditions in Geoje-Hansa Bay, which is the greatest oyster producing site in Korea. Field survey for benthic environment and macrobenthos was seasonally carried out at 15 stations covering oyster farming sites and non-farming sites from February to November, 2008. The grain size of surface sediments was dominated by very fine silt with the mean phi of about $9\;{\Phi}$ and TOC was 1.9% on average. Mean dissolved oxygen content was 8.1 mg/L and lowest in August corresponding to the 2nd degree in seawater quality criteria. Total species number was 351 and mean density was $3,675\;ind./m^2$, both of which were dominated by polychaete worms. Spatio-temporal variation in above two biological variables was great with higher values seasonally in spring and spatially in channels rather than inner bay. Dominant species were Lumbrineris longifolia (21.3%), Aphelochaeta monilaris (17.8%) and Ericthonius pugnax(6.1%), all of which are typical species of organically enriched area. From the multivariate analyses, the whole macrobenthic community was distinguished into two groups of channel and inner bay group. Spatio-temporal changes of macrobenthic community in Geoje-Hansan Bay were related to those of TOC and acid volatile sulfide (AVS). Our results showed that Geoje-Hansan Bay should be intermediately affected by organic pollution, and that such organic enrichment was more remarkable at farming stations in the inner bay.

• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.1
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• pp.1534-1548
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• 1969

This experiment was conducted, making use of the 'NONG-RIM6' arecommended variety of rice for the year of 1968. Main purposes of the experiment are to explore possibilities of; a) ways and means of saving irringation water and, b) overcoming drought at the same time so that an increased yield in rice could be resulted in. Specifically, it was tried to determine the effects of the Rotation irrigation method combined with differentiated thickness of lining upon the growth and yield of rice. Some of the major findings are summarized in the following. 1) The different thicknesses show a significant relationship with the weight of 1,000 grains. In the case of 9cm lined plot, the grain weight is 23.5grams, the heaviest. Next in order is 3cm lined plot, 6cm lined plot, control plot, and wheat straw lined-plot. 2) In rice yield, it is found that there is a considerably moderate significant relationship with both the different thickness of lining and the number of irrigation, as shown in the table. 3) There is little or no difference among different plots in terms of a) physical and chemical properties of soil, b) quality of irrigation water, c) climatic conditions, and rainfalls. 4) It is found that there is a significant relationship between differences in the method of rotation irrigation and the number of ears per hill. The plot irrigated at an interval of 7 days shows 17.4 ears and plot irrigated at an interval of 6 days, 16.3 5) In vinyl-treated plots, it is shown that both yield and component elements are greatest in the case of the plot ith whole of $3cm/m^2$ Next in order are the plot with a hole of $2cm/m^2$ the plot with a hole of $1cm/m^2$ In the case of the plot with no hole it is found that both yield and component elements are decreased as compared to the control plot. 6) The irrigation water reqirement is measured for the actual irrigation days of 72 which are the number subtracted the days of rainfall of 30 from the total irrigation days of 102. It is found that the irrigation water requirement for the uncontrol plot is 1,590mm as compared to 876mm(44.9% saved) for the 9cm-lined plot, 959mm(39.7% saved) for the 6cm-lined plot 1,010mm(36% saved) for the 3cm-lined plot and 1,082mm(32% saved) for the wheat straw lined plot. In the case of the Rotation irrigation method it is found that the water requirement for the plot irrigated at an interval of 8 days is 538mm(65% saved), as compared to 617mm(61.6% saved) for plot irrigated at an interval of 7 day 672mm(57.7% saved) for plot irrigated at an interval of 6day, 746mm(53.0% saved) for the plot irrigated at an interval of 5 days, 890mm 44.0% saved) for the plot irrigated at an interval of 4 days, and 975mm(38.6% saved) for the plot irrigated at an interval of 3 days. 7) The rate of evapotranspiration is found 2.8 around the end of month of July, as compared to 2.6 at the begining of August 3.4 around the end of August and 2.6 at the begining of August 3.4 around the end of August and 2.6 at the begining of September. 8) It is found that the saturation quantity of 30mm per day is decreased to 20mm per day though the use of vinyl covering. 9) The husking rate shows 75 per cent which is considered better.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.3
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• pp.171-188
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• 1977

The response and effect on main upland crops to potassium were discussed and summarized as follows. 1. Adequate average amounts of potash per 10a were 32kg for forage crop; 22.5kg for vegetable crops; 17.3kg for fruit trees; 13.3kg for potatoes; and 6.5kg for cereal crops. Demand of potassium fertilizer in the future will be increased by expanding the acreage of forage crops, vegetable crops and fruit trees. 2. On the average, optimum potash rates on barley, wheat, soybean, corn, white potato and sweet potato were 6.5, 6.9, 4.5, 8.1, 8.9, and 17.7kg per 10a respectively. Yield increaments per 1kg of potash per 10a were 4-5kgs on the average for cereal crops, 68kg for white potato, and 24kg for sweet potato. 3. According to the soil testing data, the exchangeable potassium in the coastal area was higher than that in the inland area and medium in the mountainous area. The exchangeable potassium per province in decreasing order is Jeju>Jeonnam>Kangweon>Kyongnam. Barley : 4. The response of barley to an adequate rate of potassium seemed to be affected more by differences in climatic conditions than to the nature of the soil. 5. The response and the adequate rate of potassium in the southern area, where the temperature is higher, were low because of more release of potassium from the soil. However, the adequate rate of phosphorus was increased due to the fixation of applied phosphorus into the soil in high temperature regions. The more nitrogen application would be required in the southern area due to its high precipitation. 6. The average response of barley to potassium was lower in the southern provinces than northern provinces. Kyongsangpukdo, a southern province, showed a relatively higher response because of the low exchangeable potassium content in the soil and the low-temperature environment in most of cultivation area. 7. Large annual variations in the response to and adequate rates of potassium on barley were noticed. In a cold year, the response of barley to potassium was 2 to 3 times higher than in a normal year. And in the year affected by moisture and drought damage, the responses to potassium was low but adequate rates was higher than cold year. 8. The content of exchangeable potassium in the soil parent materials, in increasing order was Crystalline Schist, Granite, Sedimentary and Basalt. The response of barley to potash occurred in the opposite order with the smallest response being in Crystalline Schist soil. There was a negative correlation between the response and exchangeable potassium contents but there was nearly no difference in the adequate rates of potassium. 9. Exchangeable potassium according to the mode of soil deposition was Alluvium>Residium>Old alluvium>Valley alluvium. The highest response to potash was obtained in Valley alluvium while the other s showed only small differences in responses. 10. Response and adequate rates of potassium seemed to be affected greatly by differences in soil texture. The response to potassium was higher in Sandy loam and Loam soils but the optimum rate of potassium was higher in Clay and Clay loam. Especially when excess amount of potassium was applied in Sandy loam and Loam soils the yield was decreased. 11. The application of potassium retarded the heading date by 1.7 days and increased the length of culm. the number of spikelet per plant, the 1,000 grain weight and the ratio of grain weight to straw. Soybean : 12. Average response of soybean to potassium was the lowest among other cereal crops but 28kg of grain yield was incrased by applying potash at 8kg/10a in newly reclaimed soils. 13. The response in the parent materials soil was in the order of Basalt (Jeju)>Sedimentay>Granite>Lime stone but this response has very wide variations year to year. Corn : 14. The response of corn to potassium decreased in soils where the exchangeable potassium content was high. However, the optimum rate of applied potassium was increased as the soil potassium content was increased because corn production is proportional to the content of soil potassium. 15. An interaction between the response to potassium and the level of phosphorus was noted. A higher response to potassium and higher rates of applied potassium was observed in soils contained optimum level of phosphorus. Potatoes : 16. White potato had a higher requirement for nitrogen than for potassium, which may imply that potato seems to have a higher capability of soil potassium uptake. 17. The yield of white potato was higher in Sandy loam than in Clay loam soil. Potato yields were also higher in soils where the exchangeable potassium content was high even in the same soil texture. However, the response to applied potassium was higher in Clay loam soils than in Sandy loam soils and in paddy soil than in upland soil. 18. The requirement for nitrogen and phosphorus by sweet potato was relatively low. The sweet potato yield is relatively high even under unfavorable soil conditions. A characteristics of sweet potatoes is to require higher level of potassium and to show significant responses to potassium. 19. The response of sweet potato to potassium varied according to soil texture. Higher yields were obtained in Sandy soil, which has a low exchangeable potassium content, by applying sufficient potassium. 20. When the optimum rate of potassium was applied, the yields of sweet potato in newly reclaimed soil were comparable to that in older upland soils.

• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.3
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• pp.3059-3088
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• 1973

The Object of research was laid on the dry paddy field which had a low level of underground water, rather than on a paddy field with a high level of underground water. In the treatment of the clay paddy field before transplanting we employed 3 kinds of methods; deep plowing, development of cracks by drying the surface of the field under which pipe drain was built. This study was to find which one, among these three methods, is the most effective to let roots extend to deep zone and increase the yield of rice and at the same time, for trafficability of large scale machinery which will be introduced to the harvest, in the light of the earth bearing capacity in relation with underground drainage. In the treatments of plots, 1) the kyong plot was plowed 39 days before transplanting and dried, 2) the kyun plot was plowed again 2days before transplanting after plowing 39 days before transplanting, leveling field surface in the saturation with water and developing the cracks by drying, 3) the kyunam plot was plowed again 2 days before transplanting after setting the drainage pipe and at the same time plowing 39 days before transplanting, leveling field surface in the saturation with water and developing the cracks by drying. Also each plot above had three different levels of soil depth, respectively; that is 15cm, 25cm, 35cm. The kyong plot with 15cm-depth was he control. The results obtained were as follows; 1. The kyunam plot showed a remarkably lager amount of water consumption by better underground drainage than the kyong and the kyun plot, and the kyong plot indicated a greater amount of water consumption than the kyun plot. Therefore the amount of available rainfall was decreased in the order of kyunam>kyong>kyun. The net duty of water decreased in the order of kyunam>kyong>kyun and its showed about 105cm in depth at the kyunam plot, about 70cm in depth at the kyong plot and about 45cm in depth at kyun plot, regardless of soil depth. 2. According to the tendency that the weight of the total root was effected by the maximum depth of the crack, it seemed that the root development was more affected by the depth of the crack than by only the crack itself. The weight of the total roots tended to increase as the depth of the crack got deeper and deeper, and the weight of the total roots was increased in the order of kyun<kyunam<kyong. 3. In the growing of the plant height, the difference did not appear at the beginning of growing(peak period of tillering) of any plot, But for the mid period of growing(ending period of tillering) to the period of young panicle formation, the deeper the depth of plot is, the more the growing goes down. On the contrary at the late period of growing, growth was more vigorous in the plot with deep depth than in the plot with shallow depth. Since the midperiod of growing, in the light of experimental treatment, the kyun plot was not better in growing than the other two plots and no remarkable defference was shown between the kyunam and the kyong plot, but the kyunam plot had the tendency of superiority in growing plant height. 4. As the depth of plot went deeper, the decreasing tendency was shown in the number of tillers through a whole period of growingi. When the above results were observed concering each plot of experimental treatment, the kyun plot was always smaller in the number of tiilers than the kyunam and the kvong plot, and the kyong plot was slightly larger than the kyunam plot in the number of tillers. 5. When each plot of the different experimental treatments was compared with the control plot(15-kyong), yield(weight of grains) was increased by 17% for the 35-kyong plot, by 10% for the 35-kyunam and yields for the other plots were less or nomore than the control plot. On the whole, as the depth of plot went deeper, yields for plots was increased in the order of kyong>kyunam>kyun. 1% of significance between the levels of depths and 5% of significance between the treatments were shown. 6. The depth of consumptive water which was more effective on the weight of grains is that of the last half period. When the depth of consumptive water was increased at the range of less than 2.7cm/day in the 15cm plot, 3.0cm/day in the 25cm plot and 3.3cm/day in the 35cm plot, the weight of grains was increased, and at the same time the weight of grains was increased as the depth of plot went deeper. The deeper plots was of advantage to the productivity at the same depth of consumptive water. 7. The increase in the weight of grains in propertion to the weighte of root showed a tendency to increase depending on the depth of plot at each plot of the same weight of roots. The weight of roots and grains together increasezd in the order of kyun>kyunam>kyong, considering each treatment of experimental plot. The weight of grains was in relation to the minimum water content ratio during the midperiod of surface drainage and the average earth temperature was mainly affected by the minimum water content ratio because it was relatively increased in proportion to the water content ratio(at less than 40%) 8. The weight ratio of straw to grain showed an increasing tendency at the plot of shallow depth and had a relation of an inversely exponental function to the weight of roots. At the same depth of plot except the 15cm plot, the weight ratio of straw to grain was increased in proportion to the depth of consumptive water. The weight of grains was increased as the depth of consumptive water was increased to some extent, but at the same time the weight of ratio of straw to grain was increased. 9. At a certain texture of soils the increase in the amount of the cracks depends on meteorological conditions, especially increase in amounts of pan evaporation. So if it rains during the progressing of field drying the cracks largely decrease. The amount of cracks of clay soil had relation of inversely exponental function to the water content ratio(at more than 25%). The maximum depth of crack kept generally a constant value at less than 30% of water content ratio. 10. The cone index showed the tendency that it was propertional to the amount of cracks within a certain limit but more or less inversely proportional over a certain limit. The water content ratio at the limit may be about 25%. 11. The increase in the cone index with the progressing of time after final surface drainage showed the tendency that it was proportional to the depth of consumptive water at the last half of growing period. Based on the same depth of if the cone index in the kyunam plot was much larger than in the other two plots and that in the kyong plot was much smaller than in the kyun plott, as long as the depth of plot was deeper, especially in the 35-kyong plot. 12. In the light of a situation where water content ratio of soil decreased and the cone index increased after final surface drainage the porogress of the field dryness was much more rapid in the kyunam plot than in the kyong plot and the kyun plot, especially slowest in the kyong plot. In the plot with deeper zone the progress was much slower. The progress requiring the value of the cone index, $2.5kg/cm^2$, that working machinary can move easily on the field changed with the time of final surface drainage and the amount of rainfall, but without nay rain it required, in the kyunam plot, about 44mm in total amount of pan evaporation and more than 50mm in the other two plots. Therefore the drying in the kyunam plot was generally more rapid in the kyunam plot was generally more rapid over 2days than in the kyun plot, and especially may be more rapid over 5days than in the 35-kyong plot.

• Journal of Nutrition and Health
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• v.41 no.7
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• pp.621-633
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• 2008

Diabetes mellitus (DM) is a well-established independent risk factor for cerebral infarction (CI). Additionally, the DM as well as CI are influenced significantly by health-related behaviors and diets. The aim of this study was to compare the food habits, nutrient intakes, and dietary patterns and quality in DM patients with CI (DM-CI) and without CI. This study was accomplished with 68 subjects (DM-CI group = 28, DM group = 40). Health-related behaviors, food habits, nutrient intakes and dietary quality were investigated. As a result, the mean ages and durations of diabetes in DM-CI and DM groups were $65.6{\pm}9.2$, $10.9{\pm}8.5$ and $69.2{\pm}3.0$, $9.7{\pm}8.4$ years, respectively. The health-related behaviors such as, smoking, alcohol drinking, and regular exercising in both groups were significantly different (p < 0.05) showing the number of subjects who were smoking and drinking alcohol was significantly higher in DM-CI group and the opposit result was seen for exercise. In male subjects, the intake of carbohydrate and sodium of DM-CI group were significantly higher than those of DM group (p < 0.05). In female subjects, the intake of calorie, carbohydrate, fat, sodium, and cholesterol were significantly higher in the DM-CI group (p < 0.05). Daily intake of vitamin $B_1$, vitamin $B_2$, folate, vitamin C, and calcium were significantly higher in DM group (p < 0.05). In the comparison with the dietary reference intake for Koreans (KDRI), vitamin $B_1$, vitamin $B_2$, folate, and calcium intakes were lower in DM-CI group whereas calcium and zinc intakes were in DM group. Moreover, index of nutritional quality (INQ) of vitamin $B_1$, vitamin $B_2$, vitamin C, folate, and calcium were lower significantly in DM-CI group (p < 0.05). Dietary quality including dietary diversity score (DDS), GMVDF (grain, meat, vegetable, dairy, fruit), and dietary quality index (DQI) was significantly lower in DM-CI group (p < 0.05). According to the results, diabetic mellitus patients accompanied by cerebral infarction had poorer eating patterns and dietary quality in accordance with poorer health-related behaviors compared with the DM patients without CI.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.3
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• pp.209-218
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• 2007

This experiment was conducted to investigate effect of plowing frequency and sowing dates on the agronomic characteristics, feed value, weed yield and palatability of silage corn. Treatments were a basal treatment(C: May 5 seeding, plowing once, weeding control once), T1(May 12 seeding, plowing twice, weeding control 0 time), T2(May 19 seeding, plowing three times, weeding control 0 time, T3(May 26 seeding, plowing four times, weeding control 0 time) and T4(June 2 seeding, plowing five times, weeding control 0 time). The experiment was performed at the College of Life and Natural Sciences of Sangju University in Sangju in 2006. The plant height and ear height showed highly in order to C > T1 > T2 > T3 > T4 treatment, leaf length was the highest at T2 (96.0cm). Leaf width and number of dead leaf were the highest at C and T3 (11.2cm), C, C and T1 (4.6), respectively. Stem diameter was the highest at T3 as 31mm, while T2 was the lowest as 25mm (p<0.05). Ear circle showed highly in order of C > T1 > T4 > T3 > T4 (p<0.05), and tip filling degree was the highest at C treatment as 8.8, while T4 treatment was the lowest as 6.0 (p<0.05). The stem hardness and grain hardness were C < T1 < T2 < T3 < T4 (p<0.05). Stem saccharinity was T1(6.1%) was the highest, while T2(3.0%) was the lowest(P<0.05). Fresh yield of weed was the lowest at C treatment as 500 kg/ha, but T1 treatment was the highest as 44,100 kg/ha (p<0.05). Weed coverage rate showed highly in order of T1 > T2 > T3 > T4 > C treatment (p<0.05). Fresh yield of corn was the highest at C treatment as T3,550 kg/ha, but T4 treatment was the lowest as 65,500 kg/ha (p<0.05). Dry matter yield of corn showed highly in order of C(26,978 kg/ha) > T1(26,130 kg/ha) > T2(20,255 kg/ha) > T3(20,255 kg/ha) > T4(17,508 kg/ha) treatment (p<0.05). Crude protein content was T1(7.69%) > T4(7.42%) > T2(6.34%) > T3(5.99%) > C(5.91%) treatment (p<0.05), and Crude fat content showed highly in order of C (2.13%) > T1(2.04%) > T2(1.96%) > T3(1.95%) > T4(1.84%) treatment. Relative palatability of Holstein, Korean native goat and spotted deer was the highest at C treatment, but Korean native cattle was the highest at T1 treatment.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.1
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• pp.19-28
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• 2020

This study was conducted to compare the agronomic characteristics and productivity according to the species and varieties of winter forage crops in reclaimed land. Winter forage crops used in this study were developed in National Institute of Crop Science, RDA. Oats ('Samhan', 'Jopung', 'Taehan', 'Dakyung' and 'Hi-early'), forage barley ('Yeongyang', 'Yuyeon', 'Yujin', 'Dacheng' and 'Yeonho'), rye ('Gogu', 'Jogreen' and 'Daegokgreen') and triticale ('Shinyoung', 'Saeyoung', 'Choyoung', 'Sinseong', 'Minpung' and 'Gwangyoung') were planted in the reclaimed land of Sihwa district in Hwaseong, Gyeonggi-do in the autumn of 2018 and cultivated using each standard cultivation method, and harvested in May 2019(oat and rye: 8 May, barley and triticale: 20 May.) The emergency rate was the lowest in rye (84.4%), and forage barley, oat and triticale were in similar levels (92.8 to 98.8%). Triticale was the lowest (416 tiller/㎡) and oat was the highest (603 tiller/㎡) in tiller number. Rye was the earliest in the heading date (April 21), triticale was April 26, and oat and forage barley were in early May (May 2 and May 5). The plant height was the highest in rye (95.6 cm), and triticale and forage barley was similar (76.3 and 68.3cm) and oat was the lowest (54.2 cm). Dry matter(DM) content of rye was the highest in the average of 46.04% and the others were similar at 35.09~37.54%. Productivity was different among species and varieties, with the highest dry matter yield of forage barley (4,344 kg/ha), oat was similar to barley, and rye and triticale were lowest. 'Dakyoung' and 'Hi-early' were higher in DM yield (4,283 and 5,490 kg/ha), and forage barley were higher in 'Yeonho', 'Yujin' and 'Dacheng' varieties (4,888, 5,433 and 5,582 kg/ha). Crude protein content of oat (6.58%) tended to be the highest, and TDN(total digectible nutrient) content (63.61%) was higher than other varieties. In the RFV(relative feed value), oats averaged 119, while the other three species averaged 92~105. The weight of 1,000 grain was the highest in triticale (43.03 g) and the lowest in rye (31.61 g). In the evaluation of germination rate according to the salt concentration (salinity), the germination rate was maintained at about 80% from 0.2 to 0.4% salinity. The correlation coefficient between germination and salt concentration was high in oat and barley (-0.91 and -0.92) and lowest in rye (-0.66). In conclusion, forage barley and oats showed good productivity in reclaimed land. Adaptability is also different among varieties of forage crops. When growing forage crops in reclaimed land, the selection of highly adaptable species and varieties was recommended.

• Korean Journal of Weed Science
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• v.6 no.1
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• pp.33-41
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• 1986

This experiment was conducted to determine the influence of weed competition in sesame and the periods for weed control. Competition periods (days), for which sesame was seeded under transparent polyethylene film at May 15, were 10, 15, 30, 45, 60, 75, 90, and full growth season of sesame. Weed control periods (days), for which sesame was seeded under black polyethylene film at June 15, were 10, 15, 30, 45, 60, and full growth season of sesame. Dominant weeds were Ponulaca oleracea, Digitaria sanguinalis, Acalypha australis, L. Cyperus arnuricus, Arenaria aesrphllifolia, Cardamine flexucosa, Mollugo Stricta and Digitaria eschaemum. The number of weeds was maximum at the 30 days after planting. Broad leaf weeds were dominant than grass weeds, and then decreased the total number of weeds by the reason of major decrease of broad leaf weeds. However, the weight of weeds increased continuously. No weeds appeared until the 15 days after planting and the weight of broad leaf weeds was heavier than that of grass weeds until 45 days after planting. However, grass weeds were heavier than broad leaf weeds after 60 days after planting. The hazards of weeds on the growth and development appeared seriously from the 60 to 75 days after planting, but main yield reduction appeared from 30 days after planting. Therefore once more hand weeding should be practiced within 30 days after planting to minimize yield decrease. Serious hazards by weed growing appeared by removing black PE film after 15 to 30 days after planting in growth characteristics and 30 days later in grain yield. Leaf growth showed maximum from 45 to 60 days after planting and then decreased as compared with the continuous increase of stem and root in optimum planting, transparent PE film mulch and hand weeding. Leaf growth didn't show reducing in PE film mulch and weedy check but total weight of weeds increased and growth of sesame decreased as compared to PE film mulch and hand weeding. Leaf, stem and root growth of sesame, and weed weight under black PE film mulch showed same tendancy and lower growth of sesame as compared with optimum planting, transparent PE film mulch. Correlation between sesame yield and weeds weight were r =$ -0.874^{**}$ in the optimum planting and r = $-0.712^{**}$ in the late planting, so that the more weeds increase, the lesser sesame yield.

• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.28-60
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• 1983

This study was carried out to define the effects of external factors including temperature, moisture, oxygen and light quality on the germination of sesame seeds and to investigate the change of major chemical constituents of seeds during germination. The results obtained are summarized as follows: 1. The average germination ratio was from 95.8% to 97.2% when it was tested every $5^{\circ}C$ intervals from $20^{\circ}C$ to $35^{\circ}C$ and no significant difference in germination ratio was found within $20^{\circ}C$ to $35^{\circ}C$. But the germination ratio dropped rapidly to 32.2% when seeds were germinated at $15^{\circ}C$ and the coefficient of variation become greater(77%) 2. The days required for germination ranged from 1.16 to 1. 64 at the temperatures of $35^{\circ}C$ to $25^{\circ}C$ and they were 3.07 and 10.4 at the temperatures of $20^{\circ}C$ and $15^{\circ}C$, respectively. 3. Considering the germination ratio and days needed, $15^{\circ}C$ was assumed to be the minimum temperature for germination practically and this temperature is recommended for testing low temperature tolerance of seed germination of sesame cultivars. 4. The varieties shown the highest low temperature tolerance were Shirogoma and Turkey. The next varieties shown some degree of low temperature germination were Suweon #29, Naebok and IS 58. The varieties with 70 to 80% of germination ratio were Maepo, Suweon #14, Kimpo, Moondeok, and Haenam. Among the 90 varieties tested, the varieties with comparatively high degree of low temperature tolerance were about 10%, and 70% of the low temperature tolerant varieties were domestic varieties. 5. At $12^{\circ}C$ the Shirogoma was the only variety which showed over 50% of germination ratio, 71.4% of the varieties showed less than 20% of germination ratio. When the temperature was raised to $27^{\circ}C$ 18 days after placement at $12^{\circ}C$ all the varieties showed over 90% of germination ratio within 2days. 6. The amounts of water imbibition needed for seed germination were 0.48 to 0.62 times of the seed dry weight at $25^{\circ}C$ and were significantly different among sesame cultivars. About 63% of water required for germination was imbibed in 2 hours after placement of seeds under the germination condition. 7. Under saturated moisture condition the average germination ratio was 0.42%. In the soil of which water potential was -0.4bar 64.8% of the seeds germinated and the most adequate soil water potential for sesame seed germination was about -0.4 to -5.5 bar. The germination ratio decreased as the soil water potential declined below -5.5 bar. 8. Six out of 10 varieties were not influenced by 5% of oxygen in air germination chamber, while varieties such as Yecheon, PI 158073, IS 103 and Euisangcheon showed 64 to 91% of germination under the 5% oxygen content. Under anaerobic condition, cotyledones were not emerged but only hypocotyl was emerged and elongated. The germination ratio of IS 103 decreased significantly under anaerobic condition. 9. When the seeds were dried for 24 hours after 12 hours imbibition of water, the seeds of Cheongsong did not lose their germination ability and 27.5% was germinated but Suweon #9 and Early Russian failed to germinate. However, the germination ratio of IS 103 decreased when the seed were dried 24 hours after 4 hours imbibition of water and the germination ability of IS 103 was maintained even though the seeds were dried for 24 hours after 24 hours imbibition of water. 10. During germination, sugar content of sesame seed increased rapidly and activity of ${\alpha}$-amylase increased gradually while starch content decreased significantly. The rates of increase in sugar content and enzyme activity and decrease in starch content were significantly lower at $15^{\circ}C$ compared with those at $25^{\circ}C$. 11. During germination of sesame seeds, lipid content in the seeds dropped rapidly and the activity of alkaline lipase increased significantly at early stage of germination. The rate of decrease in lipid content and increase in emzyme activity was lower at $15^{\circ}C$ than at $25^{\circ}C$. 12. Four out of 6 varieties were not affected in germination by light wave length. But Suweon #8 was inhibited in germination by 600-650nm. and IS 103 by 600 to 650nm and 500 to 550nm of light wave length. Suweon #8 showed high germination ratio under 650 to 760 nm and 500 to 560nm, and IS 103 under 400 to 470nm and complete darkness. 13. The germination ratios increased significantly in the seeds of which 1000 grain weight is heavier. When the seeds were placed at soil 4cm deep, Cheongsong and Early Russian failed to emerge their cotyledones, but Suweon #9 and IS 103 showed 32.5 and 50% cotyledone emergence, respectively. The extracts from sesame plant and soil where the sesame was cultivated previously did not affect in the-germination of sesame seeds. 14. The covering by black or transparent polyethylene films increased germination ratio compared with uncovered seeds. The covering was effective in shortening the days needed for germination and in improving the early seedling growth, number of capsules per plant and grain yield. Difference was not so seizable between the two polyethylene films but the transparent film appeared somewhat more effective than the black one. 15. Simcheon, Cheongsong. Suweon #9. PI 158073 and IS 103 showed lower rate of water absorbtion by seed during germination and Suweon #8, Suweon #26, Orotall and Euisangcheon showed high increase in seed weight after water absorbtion by seed.