• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.2
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• pp.110-115
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• 2003

The iufluence of abandonment of agricultural fields on soil carbon and nitrogen dynamics is rarely addressed due to lack of appropriately paired sites. In this study, we identified three sites that have native forest and abandoned rice and crop fields at Mt. Kumdan near Seoul. Currently the vegetation of indigenous forest and the abandoned rice field is deciduous hardwood forest, while that of the abandoned crop field is deciduous shrub. We measured soil $CO_2$ evolution and inorganic N availability for the three sites from 25 July 2002 through 24 January 2003. Soil $CO_2$ evolution tracked seasonal soil temperature. Mean soil $CO_2$ evolution (g $CO_2$/$m^2$/hr) for the study period was 0.42 for the rice field to forest, 0.50 for the crop field to shrub, and 0.41 for the indigenous forest, respectively. Soil $CO_2$ evolution and soil temperature were not different among the sites; however, soil water content was significantly different. Soil water content had a very weak influence on soil $CO_2$ evolution. Inorganic resin N availability differed among the three sites and seemed to be related to soil moisture.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.132-138
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• 1998

To improve functional properties and enhance application of FPC in food industry, modified salmon FPC with enzyme treatment was produced and its general properties were investigated. Salmon FPC has over $84\%$ of protein and less than $0.18\%$ of lipid. Solubilities of FPC extracted with IPA and ethanol were very poor as less than $3\%$ in every pH range. In case of enzyme : substrate ratio of 1 : 100, degree of hydrolysis significantly increased until 4 hours and then slightly increased. No considerable differences were observed in general components of hydrolysates. Results of SDS-PAGE showed one unique band in each case and their molecular weight was less than 6,500. The flow properties of hydrolysates showed newtonian flow. Whiteness of hydrolysates were higher than that of salmon FPC as $5\~7$. There was no significant differences in the amount of peptide, but that of free amino acid slightly increased from 0.17 to 0.21 mg/ml.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.150-157
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• 2019

This study was carried out to investigate at the micrometeorology change of the orchard according to the net installation. Two weather stations were installed at the inside of the anti-insect nets(2 mm, 4 mm), one was installed at the outside(control). They were observed the temperature, humidity, wind speed and solar radiation from April to September 2018. Daily mean temperature at the experimental group was higher than control group by $0.2^{\circ}C$. Daily mean humidity at the experimental group was higher than control group by 3.5 to 4.7%. Daily mean the solar radiation at the experimental group(2 mm) was lower than control group by 50%. The wind speed was decreased from 12% to 50% of the external wind speed at 4 mm, and from 25% to 59% at 2 mm.

• Korean Journal of Remote Sensing
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• v.40 no.2
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• pp.191-202
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• 2024

Global warming is causing abnormal climates worldwide due to the increase in greenhouse gas concentrations in the atmosphere, negatively affecting ecosystems and humanity. In response, various countries are attempting to reduce greenhouse gas emissions in numerous ways, and interest in blue carbon, carbon absorbed by coastal ecosystems, is increasing. Known to absorb carbon up to 50 times faster than green carbon, blue carbon plays a vital role in responding to climate change. Particularly, the tidal flats of South Korea, one of the world's five largest tidal flats, are valued for their rich biodiversity and exceptional carbon absorption capabilities. While previous studies on blue carbon have focused on the carbon storage and annual carbon absorption rates of tidal flats, there is a lack of research linking tidal flat area changes detected using satellite data to carbon storage. This study applied the direct difference water index to high-resolution satellite data from PlanetScope and RapidEye to analyze the area and changes of the Nakdong River estuary tidal flats over six periods between 2013 and 2023, estimating the carbon storage for each period. The analysis showed that excluding the period in 2013 with a different tidal condition, the tidal flat area changed by up to approximately 5.4% annually, ranging from about 9.38 km² (in 2022) to about 9.89 km² (in 2021), with carbon storage estimated between approximately 30,230.0 Mg C and 31,893.7 Mg C.

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.253-262
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• 2013

This experiment was conducted to investigate the effects of floor type and heating system on performance, housing environment and health status of ducks reared in three types of duck house (OD : Open floor house-Direct heating system, OF : Open floor house-Floor heating system and LD : Loft type house-Direct heating system). In OF treatment, PVC pipes were installed for heating under concrete floor and covered with litter. In LD treatment, plastic mesh was installed 50 cm above the floor so that duck's droppings can pass through it. Each treatment had four replicates of 25 birds (Cherry Valley duck breed) per pen. There were no significant differences in weight gain and feed intake of ducks for 6 weeks among all treatments. However, feed conversion ratio in LD was significantly higher (p<0.05) than that in OF. No differences were found in carcass charac- teristics, with the exception of abdominal fat weight where OF were higher than the others. Concentrations of $CO_2$ and $NH_3$ gas in OD were higher than those of OF and LD at 3, 4 and 5 weeks. Moisture content in litter of OF was lower than that of OD. In contrast, the amount of dust in the air was higher in OF than in OD. The amount of fuel used for 6 weeks in LD was lower about 21% than that in OD. Some of unusual symptoms were observed in open floor house and loft type house, such as lying, spraddle legged, twisted ankle and legs, wounded sole, or etc. No components of leukocyte and erythrocyte of blood were significantly different among all treatments. The results of this experiment showed that OF and LD systems had no positive effects on performance of meat type commercial duck. However, there were some positive effects of certain house type for the improvement of environmental condition in duck house for hygienic production. In the future, more research on the effect of various facilities and systems for duck house is needed.

• The Korean Journal of Physiology
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• v.16 no.2
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• pp.187-193
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• 1982

The relationship between water and electrolyte metabolism, and dietary intake were studied in 45 healthy Buddhist nuns who were vegetarians aged 20-34, and 28 nursing students aged 20-22 who stayed at the dormitory of Kyungpook Medical School in the Fall, 1981. The Buddhist nuns obtained significantly higher carbohydrate and total caloric intakes but significantly lower protein and lipid intakes than the female students. The Buddhist nuns excreted significantly higher urine output($1,697{\pm}68\;ml/day$, p<0. 05) and lower osmolality ($616{\pm}18\;mOsm/kg\;H_2O$, p<0.05) than the students ($1,505{\pm}67\;ml/day$ and $688{\pm}36\;mOsm/kg\;H_2O$). However, both groups excreted similar amounts of urinary $Na^+$, $K^+$ and total osmolar contents. Free water clearance of the Buddhist nuns was higher(p<0.05) than that of the students but the osmolar clearance was about the same in the two groups. Daily urine output showed good correlation with Na output (r=0.76) and osmolar clearance but not with free water clearance. Both groups showed similar values of plasma concentration of creatinine, daily excretion of creatinine and clearance. Urinary excretion of urea for Buddhist nuns was 6.4 g/day, and was significantly higher than that of the students (5.1g/day).

• Journal of Nutrition and Health
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• v.54 no.2
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• pp.165-178
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• 2021

Purpose: This study examined the eating-out patterns of Korean infants and school-aged children and compared diet quality. Methods: Data were obtained from the 2016-2018 Korea National Health and Nutrition Examination Survey. The subjects were 306 children aged 3 to 11 years old that ate dinner at restaurants. Percentage energy intakes of 24 food groups were calculated, and cluster analysis was used to identify eating-out patterns. Diet quality was assessed by calculating percentage energy and nutrient intakes using one-third of the 2015 Dietary Reference Intakes for Korean (KDRIs), nutrient adequacy ratio (NAR), mean adequacy ratio (MAR), and index of nutritional quality (INQ). Results: Cluster analysis identified 2 eating-out patterns, that is, a 'rice-centered' (53%) and a 'mixed diet' (47%) pattern. For those with the mixed diet pattern, ratios of carbohydrates, protein, and fat to total calories were 48:20:31, whereas for the rice-centered pattern, ratios were 62:15:21 (p < 0.001). Intakes of energy and most nutrients in the mixed diet pattern were excessive, but the intakes of the most nutrients in the rice-centered pattern were much lower than their KDRIs. MARs were higher for the mixed diet pattern than the rice-centered pattern (0.74 vs. 0.66) (p < 0.001), and INQs for vitamin C (p = 0.007) and calcium (p = 0.018) were lower for the rice-centered pattern, whereas INQ for iron (p = 0.003) was lower for the mixed diet pattern. Conclusion: The quality of meals for infants and school-aged children depended on eating-out patterns, but the rice-centered and mixed diet patterns both failed to provide an appropriately balanced meal pattern. The results of this study suggest that healthy menus need to be developed for children in restaurants.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.3
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• pp.2322-2341
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• 1971

The studies were conducted to determine the methods of irrigation control which is not only able to save the irrigation water as a adaptable measures for the insufficient irrigation water and the drought but also increase the yields of rice, in the paddy field which shows over percolating tendency through the couple years of 1968 and 1969 at Suwon. These experiments were carried with late maturing rice variety, Norim No. 6 and the major treatments in this experiments were filling the clay under surface soil, periodic irrigation and lining the Vinyl under the surface soil and three replicated completely randomized design was employed. Results obtained will be summarzed as follows. 1. Through the couple years, the plots tilled the clay under 15cm of the surface soil saved the irrigation water by 364% to 45% and 78% to 88% respectively. Particulary, the plot of filling the clay with 9cm thick under 15cm of the surface soil, saved the amount of irrigation water by 45% to 88% and also increased yields by 12% to 20% through the couple years. 2. The plots in which amount of 40mm of irrigation water is irrigated periodically from 5 to 8 days at the stages of tillering and ripening, saved theamount of irrigation water by 41% to 55% and also increased yields by 10% to 16% respectively through the couple years. 3. The plot lined the Vinyl under 15cm of the surface soil, saved the amount of irrigation water by 75% to 88% in accordance with the size of hole. The plot of lining the Vinyl with $3cm/m^2$ hole yielded almost same as the check plot, but in the case of lesser hole than above yielded less. 4. The plots inserted the Vinyl paper in 57cm depth and with 6cm height from the soil surface around the plot to prevent the ridge percolation reduced the amount of percolation by 25% to 33%. 5. The plot filled the wheat straw with 6cm thick under 15cm of the surface soil increased yields by 30% in former year but opposite results were gained in later year. 6. Generally, yields and yield components such as number of spikes of spikes per hill and number of grains per spike were decreased in 1969. These faots are considered to depend upon the rainy and cold weather in the stages of vigorous tillering and less sunshine in the stages of ripening. 7. The variation of characters among the plots will be summarized as follows. (1) Tallerplant height was found in the plots of clay filling and irrigation control. (2) longer culm length and higher yields were founds in the plots filled the clay with 9cm thick and controled the irrigation periodically froir 7 to 8 days. (3) Length of spike increased generally with yields but opposite tendency was found also. (4) Number of spikes per hill increased with yields in the plots of irrigation control. (5) Number of grains per spike increased with yields in the plots filled the clay with 9cm thick and controled irrigation periodically from 5 to 8 days. (6) Tendency of variation of 1000 grain weight is similar to Number of grains per spike. (7) Percentage of complete grains increased in the plot of clay filling and irrigation control.

• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.288-292
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• 2008

This study was conducted to identify the effects of irrigation amount to produce high quality melon fruit in fertigation culture. Irrigation amount of during fruit harvesting period was doubled at the low irrigation point ($(-45{\sim}50\;kPa$) treatment as 115 mm as than that of the high irrigation point ($-20{\sim}25\;kPa$) treatment. The plant growth rates such as stem length, leaf weight and plant height were a little diminished at the low irrigation point ($-45{\sim}50\;kPa$) than those of the other treatments. Internode length was however not affected by irrigation amount. Fruit weight was lighter at the low irrigation point ($-45{\sim}50\;kPa$) than that of at the high irrigation point and fruit height was shorter, but fruit diameter was not affected by irrigation amount. Fruit soluble solid was $0.9^{\circ}Bx$ higher at the low irrigation point ($-45{\sim}50\;kPa$) than at the high irrigation point ($-20{\sim}25\;kPa$) and net index was higher. Total marketable yield was highest by 3,937 kg/10a at the high irrigation point ($-20{\sim}25\;kPa$), but the excellent marketable yield was highest by 2,531 kg/10a at the low irrigation point ($-45{\sim}50\;kPa$). Inorganic contents of the soil N, K, Ca and Mg were not affected by irrigation amount. It was therefore thought that optimum irrigation point to produce high quality melon fruit by fertigation culture was $-45{\sim}50\;kPa$ at ripening stage.

• Journal of Korean Society of Forest Science
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• v.33 no.1
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• pp.33-58
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• 1977

A bark comprises about 10 to 20 percents of a typical log by volume, and is generally considered as an unwanted residue rather than a potentially valuable resourses. As the world has been confronted with decreasing forest resources, natural resources pressure dictate that a bark should be a raw material instead of a waste. The utilization of the largely wasted bark of genus Pinus, Quercus, and Populus grown in Korea can be enhanced by learning its physical and mechanical properties. However, the study of tree bark grown in Korea have never been undertaken. In the present paper, an investigative study is carried out on the bark of three genus, eleven species representing not only the major bark trees but major species currently grown in Korea. For each species 20 trees were selected, at Suweon and Kwang-neung areas, on the same basis of the diameter class at the proper harvesting age. One $200cm^2$ segment of bark was obtained from each tree at brest height. Physical properties of bark studied are: bark density, moisture content of green bark (inner-, outer-, and total-bark), fiber saturation point, hysteresis loop, shrinkage, water absorption, specific heat, heat of wetting, thermal conductivity, thermal diffusivity, heat of combustion, and differential thermal analysis. The mechanical properties are studied on bending and compression strength (radial, longitudinal, and tangential). The results may be summarized as follows: 1. The oven-dry specific gravities differ between wood and bark, further more even for a given bark sample, the difference is obersved between inner and outer bark. 2. The oven-dry specific gravity of bark is higher than that of wood. This fact is attributed to the anatomical structure whose characters are manifested by higher content of sieve fiber and sclereids. 3. Except Pinus koraiensis, the oven-dry specific gravity of inner bark is higher than that of outer bark, which results from higher shrinkage of inner bark. 4. The moisture content of bark increases with direct proportion to the composition ratio of sieve components and decreases with higher percent of sclerenchyma and periderm tissues. 5. The possibility of determining fiber saturation point is suggested by the measuring the heat of wetting. With the proposed method, the fiber saturation point of Pinus densiflora lies between 26 and 28%, that of Quercus accutissima ranges from 24 to 28%. These results need be further examined by other methods. 6. Contrary to the behavior of wood, the bark shrinkage is the highest in radial direction and the lowest in longitudinal direction. Quercus serrata and Q. variabilis do not fall in this category. 7. Bark shows the same specific heat as wood, but the heat of wetting of bark is higher than that of wood. In heat conductivity, bark is lower than wood. From the measures of oven-dry specific gravity (${\rho}d$) and moisture fraction specific gravity (${\rho}m$) is devised the following regression equation upon which heat conductivity can be calculated. The calculated heat conductivity of bark is between $0.8{\times}10^{-4}$ and $1.6{\times}10^{-4}cal/cm-sec-deg$. $$K=4.631+11.408{\rho}d+7.628{\rho}m$$ 8. The bark heat diffusivity varies from $8.03{\times}10^{-4}$ to $4.46{\times}10^{-4}cm^2/sec$. From differential thermal analysis, wood shows a higher thermogram than bark under ignition point, but the tendency is reversed above ignition point. 9. The modulus of rupture for static bending strength of bark is proportional to the density of bark which in turn gives the following regression equation. M=243.78X-12.02 The compressive strength of bark is the highest in radial direction, contrary to the behavior of wood, and the compressive strength of longitudinal direction follows the tangential one in decreasing order.