• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.385-397
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• 1982

The climatic impacts have been the environmental constraints with soil characteristics to achieve self sufficiency of food production in Korea. In this paper, the distribution and appearance of impacts and the changes in climatological status due to recent trend of early transplanting of rice are widely discussed to derive some countermeasures against the impacts, being focussed on cultural A long term analysis of the climatic impact appearances of the last 74 years showed that drought, strong wind, flood, cold spell and frost were the major impacts. Before 1970's, the drought damage was the greatest among the climatic impacts; however, the expansion and improvement of irrigation and drainage system markedly decreased the damage of drought and heavy rain. The appearance of cold damage became more frequent than before due to introduction of early transplanting for more thermophilic new varieties. Tongillines which were from Indica and Japonica crosses throw more attention to cold damage for high yields to secure high temperature in heading and ripening stages and lead weakness to cold and drought damage in early growth stage after transplanting. The plants became subject to heavy rain in ripening stage also. For the countermeasures against cold damage, the rational distribution of adequate varieties according to the regional climatic conditions and planting schedule should be imposed on the cultivation. A detoured water way to increase water temperature might be suggestable in the early growth stage. Heavy application of phosphate to boost rooting and tillering also would be a nutritional control method. In the heading and ripening stages, foliar application of phosphate and additional fertilization of silicate might be considerable way of nutritional control. Since the amount of solar radiation and air temperature in dry years were high, healthy plants for high yield could be obtained; therefere, the expansion of irrigation system and development of subsurface water should be performed as one of the national development projects. To minimize the damage of strong wind and rainfall, the rational distribution of varieties with different growing periods in the area where the damage occurred habitualy should be considered with installation of wind breaks. Not only vertical windbreaks but also a horizontal wind break using a net might be a possible way to decrease the white heads in rice field by dry wind. Finally, to establish the integrated countermeasures against the climatic impacts, the detailed interpretation on the regional climatic conditions should be conducted to understand distribution and frequency of the impacts. The expansion of observation net work for agricultural meteorology and development of analysis techniques for meteorological data must be conducted in future together with the development of the new cultural techniques.

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.2
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• pp.89-97
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• 2018

This study was conducted to elucidate the effect of after-ripening of gourd fruits before seed collection. Five varieties of commercial gourd varieties were cultivated and the fruits were picked after 24, 31, 50, and 70 days from pollination. For after-ripening treatments the fruits were placed for five days in a cool, air-circulated place while a number of fruits were placed for longer periods to 85 days including growing period, 24 + 62 days, 31 + 55 days, 50 + 35 days, and 70 + 15 days. The seeds collected from fruits harvested on 24^th day were not emerged at all, but the seeds from after-ripening treatment for 62 days showed 78% emergence or higher. The growth of seedlings showed the effects of after-ripening treatment of the fruits before seed collection; the seeds collected after ripening treatment showed better hypocotyl growth and larger embryo size than the non-treated seeds.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.327-338
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• 2020

In recent years, the temperature of Korea has been rapidly increasing due to global warming. Over the past 40 years, the temperature of Korea has risen by about 1.26℃ compared to that in the early 1980s. By region, the west region of the Gangwon Province was the highest at 1.76℃ and the Jeonnam Province was the lowest at 0.96℃. As the temperature continues to rise, it is expected that the rice yield will decrease in the future using the current standard cultivation method. As a result of global warming, the periods in which rice cultivation could be possible in regions each year has increased compared those to the past, showing a wide variety from 110 days in Taebaek to 180 days in Busan and Gwangyang. In addition, the transplanting time was delayed by 3-5 days in all regions. The average annual yield of rice showed an increasing trend when we analyzed the average productivities of developed varieties for cooked rice since the 1980s, especially in the early 1990s, which showed a rapid increase in productivity. The relationship between the average temperature at the time of development and the rice yield was divided into the periods before and after 1996. The higher the average temperature, the lower the yield of the developed varieties until 1996. However, since 1996, the increase in the average temperature did not show a trend in the productivity of the developed varieties. The climate change adaptability of developed rice varieties was investigated by analyzing the results of growing crops nationwide from 1999 to 2016 and the change in the annual yields of developed varieties and recently developed varieties as basic data to investigate the growth status of the crops in the country. As a result of annual comparisons of the yields of Taebongbyeo (2000) and Ungwangbyeo (2004) developed in the early 2000s for Odaebyeo, which was developed in the 1980s, the annual yields were relatively higher in varieties in the 2000s despite the increase in temperature. The annual yields of Samgwangbyeo (2003) and Saenuribyeo (2007), which were recently developed as mid-late-type varieties, were higher than those of an earlier developed variety called Chucheongbyeo, which was developed in the 1970s. Despite the rapid increase in temperature, rice cultivation technology and variety development are well adapted to climate change. However, since the biological potential of rice could reach its limit, it is necessary to develop continuous response technology.

• Magazine of the Korean Society of Agricultural Engineers
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• v.10 no.1
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• pp.1388-1393
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• 1968

Higher yield in rice paddies is greatly dependent on adequately balanced and timely supply of water. A majority of rice paddy in Korea is generally irrigated by rainfall, but in many cases it has to be supplemented by artificial irrigation for optimum rice culture. Although the water requirement of rice plant is far higher than that of other crops, submerged condition of rice paddy is not necessarily required. The moisture requirement of rice plant varies with its growing stages, and it is possible to increase the irrigation efficiency through reduction of water loss due to percolation in rice paddies. An experiment was conducted on the effectiveness of economical use of water by different irrigation period and different method of cultivation. The experimental plots were set up by means of randomized block design with three duplications; (a) Alltime submerged (b) Economically controlled, and (c) Extremely controlled. Three different irrigation periods were (a) Initial stage (b) Inter-stage, and (c) last stage. The topsoil of the three plots were excavated to the depth of 30cm and then compacted with clay of 6 cm thickness. Thereafter, they were piled up with the excavated top soils, leveled and cored with clay of 6cm thickeness arround footpath in order to prevent leakage. The results obtained frome the experiments are as follows; (1) There is no difference among the three experiment plots in terms of physical and chemical contditions, soil properties, and other characteristics. (2) Colulm length and ear length are not affected by different irrigation methdos. (3) There is no difference in the mature rate and grain weight of rice for the three plots. (4) The control plot which was irrigated every three days shows an increased yield over the all the time submerged plot by 17 persent. (5) The clay lined plot whose water holding capacity was held days long, needs only to be irrigated every 7 days. (6) The clay lined plot showes an increased yield over the untreated plot; over all the time submerged plot by 18 percent, extremely controlled plot by 18 percent, and economically controled plot by 33 percent.

• Korean Journal of Organic Agriculture
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• v.19 no.2
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• pp.199-214
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• 2011

This study was conducted to investigate the effect of organic dietary metabolizable energy (ME) and crude protein (CP) on productivity, meat quality and blood composition of crossbred chicks (hanhyub 3 ho) for different growring periods. Experiments were factorially designed with ME 3,000, 3,100kcal/kg and CP 21, 22, 23% for starter (0-4wks); ME 3,100, 3,150, 3,200kcal/kg and CP 18, 19, 20% for grower (5-8wks); ME 3,100, 3,150, 3,200kcal/kg and CP 15, 16, 17% for finisher (9-10wks). The total number of chicks and replicate of each treatment for starter, grower, finisher were 720, 4; 702, 6; 468, 4, respectively. The diets was mixed with more 90% organic feed ingredients. The productivity were not influence by dietary ME for starting period. Weight gain and feed intake were significantly increased in CP 23% treatment than CP 21, 22% treatment (P<0.05). FCR was improved as dietary CP increased (P<0.05). Weight gain was tended to be increased by decreaing ME content and increasing CP contents for growing period. Feed intake showed no difference among the ME and CP treatment groups. FCR improved significantly in CP 19, 20% compared with CP 18% (P<0.05). Weight gain was not significantly different between ME and CP treatments for finishing period. Feed intake was lower in ME 3,150, 3,200kcal/kg than the ME 3,100 kcal/kg treatment (P<0.05). FCR was higher in ME 3,100kcal/kg than ME 3,150, 3,200kcal/kg treatment (P<0.05). Interaction on productivity was not exited between ME and CP treatment groups for different feeding periods. There was no difference in the total protein, albumin, glucose and triglyceride amount in blood depending on dietary ME and CP contents. Total cholesterol was greatly decreased in ME 3,100kcal/kg than the ME 3,200kcal/kg (P<0.05), but not different between CP treatments. Cooking loss of breast meat was lower in ME 3,150kcal/kg than the ME 3,200kcal/kg (P<0.05). Moisture, shear force and pH were not statistically different among treatments. Protein solubility was increased by increasing ME and CP in diets. The collagen was tended to increase as dietary ME increased. Redness was remarkably higher in ME 3,150kcal/kg than the ME 3,100kcal/kg (P<0.05). Yellowness of meat fed ME 3,150kcal/kg showed significantly lower than other treatments (P<0.05). Therefore, the optium ME and CP to improve the productivity for each period were 3,000kcal/kg, 23%; 3,100kcal/kg, 19%; 3,150kcal/kg, CP 16%, repectively.

• Korean Journal of Medicinal Crop Science
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• v.13 no.1
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• pp.11-16
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• 2005

Soybean sprouts presoaked to leaf extracts were on sale as taking a growing concern about wellbeing foods. The study was carried out to compare the effects of culture period after presoaking tea (Thea sinensis L.) and hard rubber tree (Eucommia ulmoides Oliver) leaf extracts on lateral root formation, growth and morphological characters of the sprouts. Seeds of three cultivars, Pungsannamulkong, Sowonkong and Junjery, were imbibed for 5 hours into 10% solutions immediately before 5, 6 and 7 day cultures. The cultured sprouts were classified into 4 categories to calculate their composition rates on the base of hypocotyllengths; >7 cm (A),4 to 7 cm (B),< 4 cm (C) and not germinated (D), and their morphological characters, fresh and dry weights were measured. Rate of A was the lowest in Junjery of the three cultivars, while that of C showed reverse result compared to A. Similar results to that of A were observed between the three cultivars in sprout length including hypocotyl and root, diameters in middle and hook parts of hypocotyl, total fresh and dry weights. Regardless of tea and hard rubber tree leaf extract treatments, longer culture periods increased rate of A due to decrements of B, C and D, and also did the growth and the morphological characters mentioned above. Although longer culture periods reduced the increment of lateral roots, the latter treatment was more delayed in their formation and less in the roots per sprout than the former one. The growth and the morphological characters above were less in the latter treatment than in the former one in general, meaning that hard rubber tree leaf extract could more repress growth of soybean sprouts than tea leaf extract.

• Journal of the Korean Geographical Society
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• v.28 no.1
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• pp.1-15
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• 1993

This research aims to investigate some respects of chemical weathering processes, espcially the amount of solute leaching, formation of clay minerals, and the chemical weathering rate of granite rocks under present climatic conditions. For this purpose, I investigated geochemical mass balance in a small catchment and the mineralogical composition of weathered bedrocks including clay mineral assemblages at four res-pective sites along one slope. The geochemical mass blance for major elements of rock forming minerals was calculated from precipitation and streamwater data which are measured every week for one year. The study area is a climatically and litholo-gically homogeneous small catchment($3.62Km^2$)in Anyang-shi, Kyounggi-do, Korea. The be-drock of this area id Anyang Granite which is composed of coarse-giained, pink-colored miner-als. Main rock forming minerals are quartz, K-Feldspar, albite, and muscovite. One of the chracteristics of this granite rock is that its amount of Ca and Mg is much lower than other granite rock. The leaching pattern in the weathering profiles is in close reltion to the geochemical mass balance. Therefore the removal or accumulation of dissolved materials shows weathering patterns of granite in the Korean peninsula. Oversupplied ions into the drainage basin were $H^+$, $K^+$, Fe, and Mn, whereas $Na^2+$, $Mg^2+$, $Ca^2+$, Si, Al and $HCO-3^{-}$ were removed from the basin by the stream. The consumption of hydrogen ion in the catchment implies the hydrolysis of minerals. The surplus of $K^+$ reflects that vegetation is in the aggravation stage, and the nutrient cycle of the forest in study area did not reach a stable state. And it can be also presumed that the accumulation of $K^+$ in the top soil is related to the surplus of $K^+$. Oversupplied Fe and Mn were presumed to accumulate in soil by forming metallic oxide and hydroxide. In the opposite, the removal of $Na^+$, Si, Al resulted from the chemical weathering of albite and biotite, and the amount of removal of $Na^+$, Si, Al reflected the weathering rate of the bedrock. But $Ca^2+$ and $Mg^2+$ in stream water were contaminated by the scattered calcareous structures over the surface. Kaolinite is a stable clay mineral under the present environment by the thermodynamical analysis of the hydrogeochemical data and Tardy's Re value. But this result was quite different from the real assemblage of clay miner-als in soil and weathered bedrock. This differ-ence can be explained by the microenvironment in the weathering profile and the seasonal variation of climatic factors. There are different clay forming environments in the stydy area and these differences originate from the seasonal variation of climate, especially the flushing rate in the weathering profile. As it can be known from the results of the analysis of thermodynamic stability and characteristics of geochemical mas balance, the climate during winter and fall, when it is characterized by the low flushing rate and high solute influx, shows the environmental characteristics to from 2:1 clay minerals, such as illite, smectite, vermiculite and mixed layer clay minerals which are formed by neoformation or transformation from the primary or secondary minerals. During the summer and spring periods, kaoli-nite is a stable forming mineral. However it should consider that the other clay minerals can transformed into kaolinite or other clay minerals, because these periods have a high flushing rte and temperature. Materials which are directly regulated by chemical weathering in the weathered bedrock are $Na^+$, Si, and Al. The leaching of Al is, however, highly restricted and used to form a clay mineral, and that of Si falls under the same category. $Na^+$ is not taked up by growing veget ation, and fixed in the weathering profile by forming secondary minerals. Therefore the budget of $Na^+$ is a good indicator for the chemical weathering rate in the study area. The amount of chemical weathering of granite rocks was about 31.31g/$m^2+$/year based on $Na^+$ estimation.

• Journal of Preventive Medicine and Public Health
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• v.17 no.1
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• pp.173-192
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• 1984

On the basis of the study intended to research by crosssectional study keeps pace with semilongitudinal study the growthaccelerating phenomena that Maximum Growth age in teenager's body-height. By the random sampling method, the subject of study are 12659 persons(male; 6355, female; 6304) that they are from 7 ages to 17 ages in the whole country including the rural community. The measurement period passed three month days, the statistical data became electronic data processing system with computer. The other side, body-height and MGA of Koreans who had been for during the period from 1925 to 1966 proved transition of the growth-accelerating phenomena by research data reported between 1913 and 1983. The results are as follows; 1. The Growth and Development-Value of Body-height An age bracket the growth and development-value of body-height were, respectively, male is $123.88{\pm}5.05cm$ and female is $123.29{\pm}5.54cm$ for 7 ages group. these indices increased with age. the top-value reach, respectively. $169.08{\pm}5.62cm$ and $157.57{\pm}6.13cm$. The intersecting ages of male and female were the age $8.5{\sim}12.5$, during these periods, female excelled male but after these periods, male excelled female again. In case of body-height, MGA's are 7.0cm for male between 12 and 13 ages, and 7.01cm for female between 8 and 9 ages. As a rule, body-height of male excelled female but intersection phenomena of male and female appeared between 8.5 and 12.5 ages. By reginal groups, it is most prevailing is Seoul, and medium size cities and rural community rome in order. By regional groups, intersection phenomena of male and female are. a region of Seoul; $$8.5{\sim}11.5$$ ages a region of Daejeon; $$7.5{\sim}9.5$$ ages rural community; $$11.5{\sim}14.5$$ ages the whole country's average; $$8.5{\sim}12.5$$ ages By regional groups, the rate of maximum increase in a year are a region of Seoul; male is 7.23cm as 13 ages female is 7.65cm as 9 ages. a region of Daejeon; male is 7.85cm as 11 ages. female is 8.39cm as 9 ages. rural community; male is 7.65cm as 14 ages. female is 6.25cm as 12 ages. the whole country's average; male is 7.0cm as 13 ages. female is 7.01 as 9 ages. 2. Maximum Growth Age (M.G.A.) By reginal groups, maximum Growth Age's are as below in a region of Seoul, MGA's are 12.63 for male and 9.01 for female, which shows that MGA for female appears about 3.5 years earlier than that for male. In a region of Daejeon, MGA's are 9.20 for male and 8.93 for female, which. show that they are all much the same in M.G.A. In rural community, MGA's are 14.00 for male and 11.89 for female, which shows that MGA for female apperars about 2 years earlier than that for male. In the whole average, MGA's are 13.01 for male and 8.97 for femal, which shows that for female appears about 4 years earlier than that for male. For boy, M.G.A. shows fastest-growing in Daejeon, and Seoul and rural commonly come in order. For girl, It shows equal growth in Seoul and Daejeon, rural community comes later. 3. The M.G.A's in body height of male are respectively the age 15.02 in 1913, 14.23 in 1956, 13.86 in 1967, 13.62 in 1975, and 12.82 in 1981, while those of female are the age 12.0 in 1940, 11.52 in 1965, 9.53 in 1975, and 11.16 in 1980; these data show that the MGA of the Koreans has been getting younger. 4. The equation of linear regression of all the MGA's in body height are as follow; Male: Y(M.G.A)=$-0.020{\times}$ (the year)+15.19: female:Y(MGA)=$-0.028{\times}$(the year)+13.2549. 5. The corelation of all the MGA's in body height are as below; male; r=-0.329 female;r=-0.252 6. From the transition of the growth-accelating phenomena in 1980 we can capture the fact that the MGA's has been getting younger by 0.2 year per 10 years. 7. The MGA's in bodyheight are shown in table 4... 8. The future growth-accelating phenomena in body height are expected to show the similar tendency like that of the past, in 1910's but it should by more precisely reviewed after investigating the phenomena of the years directly ahead.

• Korean Journal of Poultry Science
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• v.13 no.2
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• pp.179-186
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• 1986

A total of 749 Korean native Ogol fowl[Natural Monument No, 265] and 45,340 Ogol eggs were used to investigate the various performances of Ogol, I. e., fertility, hatchability, viability, body weight, and rate of egg production. The studying periods was from May, 1985 to Sept., 1986. The results obtained are summarized as follows. 1. The mean rates of fertility and hatchability were 82.2${\pm}$1.37(X${\pm}$S.E.) and 79.0${\pm}$1.91%, respectively. 2. The mean rates of fertility and hatchability during brooding, growing and laying periods were 90.5${\pm}$1.69, 79.9${\pm}$2.28% and 80.6${\pm}$3.06%, respectively. 3. Average body weight at hatch, at ages of 18, 24, 44 and 72 weeks were 31.5, 0.43, 1209.3${\pm}$17.29, 1646.1${\pm}$25.90, 1975.3${\pm}$40.56 and 2096.7${\pm}$40.83g, respectively. 4. The age of the first egg was 166.5${\pm}$1.69 days old. Egg weights at first egg, at ages of 44 and 72 weeks were 35.7${\pm}$0.49, 48.8${\pm}$0.47 and 502${\pm}$0.44g, respectively. The numbers of egg production age to of 44 and 72 weeks were 69.5${\pm}$3.10 and 129.3${\pm}$5.56 eggs, respectively. 5. Between body weights and age at the first egg showed lower negative correlation. Body weights at ages of 24, 44 and 72 weeks showed highly positive correlation with egg weight, but a significant negative correlation with the number if egg production to ages of 44 and 72 weeks. The age at first egg was positively correlated with egg weight at first egg, but that was negatively correlated with the number of egg production to ages of 44 and 72 weeks.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.1018-1023
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• 2010

Climatic change was observed and analyzed in view of impacts on agricultural ecosystem, inter alia on rice cropping. The changed climate gave rise to earlier transplanting of rice seedling and later harvest after 40 years. Also phenological change and prolonged growth duration was observed. The meteorological data was selected from the standardized climatological data of 30 year normals of 1960s and 2000s, which were published by Korea Meteorological Administration. Development stages and growing periods of rice crop were compared by analyzing critical and optimum temperatures of each growth stage during these two periods. The first appearance date of $15^{\circ}C$ was ranged from Apr. 29 to May 23 in the year-normals of 1960s and it varied from Apr. 24 to May 16 in the normals of 2000s. The difference of the first appearance date of $15^{\circ}C$ was 0~10 days earlier in the year-normals of 2000s than the 1960s. The last harvesting date was determined to be the last appearance date of mean air temperature $15^{\circ}C$. The difference in the last appearance date of $15^{\circ}C$ was 1 to 13 days later in the year-normals of 2000s than in 1960s. The plant height of a rice variety, Hwayoung-byeo was 101~109 cm in 4 local areas, Seoul, Kangneung, Kwangju and Daegu. The plant height became 1~4 cm taller under warm condition. Rice grain yields estimated with daily weather data for the year-normals of 1960s and 2000s were 453~580 kg $10a^{-1}$ and 409~484 kg $10a^{-1}$ respectively. Rice grain yield of the former period was 50~100 kg $10a^{-1}$ higher than that hat in the later period.