• Korean Journal of Poultry Science
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• v.25 no.4
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• pp.169-175
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• 1998

A feeding trial was carried out to evaluate optimum feeding system to Korean Native Chicken (KNC) with various feeding programs for 64 weeks. Eight hundreds and ten KNC＇one day birds were assigned to three feeding systems, NRC(T1), Japanese Feeding Standard(T2), Korean Feeding Standard(T3). Each treatment had three replicates of 90 birds a replicate. Data were obtained growing performance to 20 week of age and laying performance from twenty one to sixty four week. Viability to 20 week of age was similar to treatments. Growth characteristics by feeding systems were not significantly difference on body weight, feed intake and 50％ egg production days. However, body weight was less about 100g in T2. There were no different on egg production, egg weight, and egg mass during laying period. Feed intake of T1 was 104g daily and showed lower than other treatments, but was not different significantly. Feed conversion was significantly improved in T2(P <0.05) compared to other treatments(P<0.05). Egg production of all treatments was the highest between 27 to 30 week of age. ME intake of T1 was significantly maximized, whereas CP intake was the lowest of all treatments(P < 0.05). Nutrient requirements for egg mass tended to depend on nutrients intake. Interior egg and eggshell characteristics were not different among treatments except yolk color. Fertility and hatchability were similar to treatments, and the results at 39 week of age were higher than at 62 week in all treatments. In conclusion, treatments fed three or four phase feeding would be superior to other treatments during the growing period and suggest 2,800 ㎉/kg ME, 15％ CP for Korean native laying hen.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.2
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• pp.108-113
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• 1984

To find out the differences in micro-meteorological changes in the rice plant canopy at the different growing stages, Seokwang-byo, a high yielding variety, was cultivated with three planting densities of 50, 80 and 110 hills per $3.3m^2$ in 1982, and Seokwangbyo and Chucheong-byo, a local variety, were planted with a density of 80 hills per $3.3m^2$. Air temperature in plant canopies, water and soil temperatures were continuously monitored throughout the growing period. The relationship between solar radiation interception and leaf area indices at different height in the canopy also was studied. The results were as follows: 1. Air temperature in the densely planted canopy was 1 to $1.5^{\circ}C$ higher than that in the sparsely planted one at the early growing stage, but was inverted after 60 days of transplanting. The vertical distribution of temperature in the canopies showed that air temperature at 10 cm height from the ground was higher than that at 30 cm height. The temperature inversion occurred showing lower temperature at the 10 cm height than at the 30 cm height. 2. The highest temperature of a day in the canopy occurred at 14:00 to 15:00 Korean Standard Time same as that of air temperature, but approached to the solar noon time as the plants grew thick. 3. The air temperature in the canopy became higher than water temperature when the leaf area indices were 4.6 for Chucheongbyo and 5.2 for Seokwangbyo, and the light penetration ratios were 40 percents. 4. Light extinction coefficients of the 50 to 70 cm layer of the canopies were 0.3 to 0.5 but decreased at the lower layers. 5. Albedo of the canopies was 0.4 in the morning and evening while that was about 0.25 at noon. The difference in albedo between Seokwangbyo and Chucheongbyo could be recognized with the difference in leaf structure.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.4
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• pp.232-242
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• 2002

To investigate the effects of arbuscular mycorrhizal (AM) fungus (Glomus intraradices) colonization on drought-stress tolerance, leaf water potential, chlorophyll concentration, P content and carbohydrate composition were examined in perennial ryegrass (Lolium perenne L.) plants exposed to drought-stressed or well-watered conditions. Drought stress significantly decreased leaf water potential, P content and leaf growth. These drought-induced damages were moderated by mycorrhizal colonization. Drought stress decreased the concentration of soluble sugars in shoots. AM plants had a higher foliar soluble sugar than non-AM plants under drought stress condition. Drought stress depressed the accumulation of starch and fructan in shoots, but stimulated in roots. Under drought-stressed condition, starch concentration in roots was higher in non-AM plants than in AM plants. Fructan was the largest pool of carbohydrates, showing the highest initial concentration and the highest net increase for 28 days of treatment. Drought stress slightly decreased fructan concentration in shoots, but remarkably increased in roots. Under drought-stressed condition, fructan concentrations in non-AM and AM shoots at day 28 were 18.7% and 13.3% lower than the corresponding values measured at well-watered plants. However, in the roots, fructan accumulation caused by drought was lessen 13.6% by mycorrhizal colonization. The results obtained suggest that mycorrhizal colonization improves drought tolerance of the host plants by maintaining higher leaf water status and P status, and by retaining more foliar soluble sugars.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.667-682
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• 2014

The effects of liquid pig manure (LM) on the yield and quality of rice as well as soil chemical properties were determined in the field of sandy loam soil under the different fertilizer management. Treatments consisted of 100%, 130% and 160% N application rates of liquid manure as calculated on the basis of the recommended rate of nitrogen (9 kg N/10a) for rice cultivation. Chemical fertilizer (CF) was used as control. Concentrations of T-N and T-P in paddy water were measured by 5-day intervals up to 20days after application. LM treatments significantly increased T-N concentrations in paddy water proportionally with increasing rates of LM (13.2 to 25.7 mg/L). Similarly Total-P content in paddy water was increased right after LM applications but was well below the quality standard of wastewater and manure. Plant height and tillers in 100% and 130% N LM treatments were lower than those in CF control. In the 160% LM treatment, however, plant height and numbers of tillers were higher than those in the CF control. Yields in 100% LM and 160% LM plots were decreased by 3 and 5%, respectively, as compared with 422 kg per 10a in the CF plot. Rice protein contents were similar between 100% LM and CF control (about 6.8%) but it was increased to 7.2% and 7.7% in 130% LM and 160% LM treatments, respectively. Toyo-taste value in the 100% LM treatment was higher than in CF control plot. The proportions of perfect grain of the brown rice were lower in 130% LM and 160% LM treatments than that in CF control. Soil organic matter content, heavy metal and exchangeable cations were highest in the 160% LM plot. Thus considering yield and quality of rice and heavy metals contents in soil, 130% N basal application of liquid manure can be recommended for rice cultivation in this experiment.

• Korean Journal of Breeding Science
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• v.43 no.3
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• pp.184-189
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• 2011

'Younghan' (Hordeum vulgare L.), a winter barley for forage use, was developed by the breeding team at the Department of Rice and Winter Cereal Crop, National Institute of Crop Science, Rural Development Administration in 2008. It was derived from a cross between $F_1$['YB3433-3B-5'/'YB3135-3B-2-3'] and 'YB3135-3B-2-3'. 'SB971305-B-B-B-4-4' line was selected for its earliness, resistance to disease and good agronomic characteristics. The promising line showed both high yield and lodging resistance in the yield trials in Iksan in 2004 to 2005, and designated as 'Iksan420'. The line was subsequently evaluated for winter hardiness, earliness, and yield at eight locations throughout Korea for two years from 2007 to 2008 and finally named as 'Younghan'. It has the growth habit of IV, erect plant type, green leaf and thick culm in diameter. Its heading date was April 24, and the maturing date was May 25 in paddy field conditions, which were one day earlier than those of the check cultivar 'Youngyang'. The cultivar 'Younghan' had better winter hardiness, and resistance to lodging and BaYMV than those of the check cultivar did. The average forage dry matter yield of 'Younghan' was approximately 12.0 MT/ha in adapted region. 'Younghan' also showed 8.5% of crude protein content, 27.2% of ADF, and 67.1% of TDN, including higher grade of silage quality for whole crop barley. This cultivar would be suitable for (area with daily minimum temperature in January) above $-8^{\circ}C$ in Korean peninsula.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.2
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• pp.118-130
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• 2007

The steep-sloped agricultural land was severely damaged by rainfall events during July and August every year. The objective of this study was to investigate an effects of intensive rainfall to the soil properties of the steep-sloped agricultural land. Survey sites including the Sacheon myeon area were located in Gangneung, those were severely damaged from a forest fire in April 2000. Surveys were taken at these sites after two years of forest fire and severe rainfall events in August 2002, which included an event that poured with 870 mm of rainfall in a day. After this storm, soil erosion, burying, and flooding were observed. Severe soil loss was found at lower soil-depths, greater slopes, longer slope lengths, and concave landscapes. Soil loss and land slides were often found at areas with having a coarser textures, higher bulk densities, lower water holding capacity, and lower rates of soil aggregation. Crop growth stagnation was found at the site of crop restoration because of low soil fertility and poor drainage caused by the abrupt textural changes. In conclusion, it is necessary to manage the steep-slope agricultural land based on environmental impact assessment data of macro morphological and physical characteristics by intensive rainfall.

• Korean Journal of Organic Agriculture
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• v.27 no.1
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• pp.33-44
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• 2019

This study was initiated to find possibility of substitute of gibberellin acid and to prevent negative girdling effect such as slow growth of 'Niitaka' (Pyrus pyrifolia Nakai) trees, a major pear cultivar, at harvest and at 60-, 90-, and 120-d after storage. Seasonal wiring with 3.0-mm-diameter were applied on the main branch at 70, 80, 90, 110, and 130 days after full bloom (DAF) to compare the fruit quality and storability. Fruit weight and sugar contents were the greatly increased by the wiring treatment at 110 DAF, with the lowest values observed for the wiring at 70 DAF. All the wiring treatments reduced fruit acidity but did not affect fruit firmness. a-value on fruit skin was the highest for wiring at 110 DAF and 130 DAF, advancing fruit ripening. The lowest fruit weight loss was occurred at wiring at 110 DAF. a-value on fruit skin was the highest for wiring at 90 DAF and 110 DAF. Wiring at 80 DAF the most increased floral bud diameter, resulting in the lowest L:D ratio of 1.74 observed. As for the mineral nutrients concentrations of floral buds, the concentration of K (0.63%) and Mg (0.31%) were the highest after 80 DAF wiring treatment, whereas Ca and P concentrations did not differ among treatment plots. The leaf K concentrations was the highest in the 130-day wiring treatment (0.76%) and in the control plot (0.78%), whereas there was no significant difference in the concentrations of either Ca or P among treatment plots. Short periods of wiring increased foliar Mg concentrations. In floral buds, carbohydrates showed a tendency for accumulating at a lower concentrations (7.75%) after 70 DAF wiring treatment, which was a relatively short treatment period. On the other hand, the carbohydrate concentrations in leaves showed a tendency for accumulating at lower concentrations after 130 DAF wiring treatment (2.51%), which is a long treatment period, and in the control plot (2.43%). Wiring increased the size and sugar content of fruits, and influenced fruit storability. For the wiring treatment period was delayed, the carbohydrate concentration in flower buds showed curvilinear correlation and the negative correlation with the carbohydrate in leaf tissue.

• Journal of Food Hygiene and Safety
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• v.34 no.1
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• pp.94-99
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• 2019

The objective of this study is to establish the shelf life of non-pasteurized whole egg, egg yolk and egg white liquid. Each sample was stored for two weeks at $5^{\circ}C$, $10^{\circ}C$, $15^{\circ}C$, and $25^{\circ}C$, and then sensory, microbial, and physicochemical tests were performed periodically. The estimation of shelf life was based on the microbial standards of total viable counts and coliforms. The chemical properties highly correlated with the sensory evaluation were also used. Our results showed that the shelf life was the most influenced by microbial properties. Exceptionally, however, whole egg and white liquid stored at $5^{\circ}C$ and $10^{\circ}C$ with limited bacterial growth were affected by chemical property. The shelf life of the three non-pasteurized liquids was calculated to be less than one day at over $15^{\circ}C$. At $5^{\circ}C$ and $10^{\circ}C$, the shelf life was calculated to be 5 d and 1 d for egg yolk liquid, 5 d and 5 d for egg white, and 7 d and 5 d for whole egg, respectively. Therefore, it is advisable to establish reasonable shelf life in the more specific manner based on consideration of these findings.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.478-484
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• 2018

A soybean cultivar "Chamol" for double cropping for use as soy-paste and tofu was developed using a pedigree method in 2011 as a cross between "Shinpaldal2" and "Keunol." A promising line, SS99502-2B-89-1-3-4-1-1, was selected and designated as "Milyang210". It was promising and showed good results from regional yield trials (RYTs) for 3 years from 2009 to 2011 and released with the name "Chamol." It has a determinate growth habit, white flowers, gray pubescence, yellow seed coat, yellow hilum, spherical seed shape, and large seeds (27.7 g per 100 seeds). The maturity date of "Chamol" was September 18 (100 day growing period) in RYT and it is suitable for double cropping with winter crops such as onion. "Chamol" was resistant to bacterial pustule and soybean mosaic virus and tolerant to lodging in fields. Furthermore, the average yield of "Chamol" was 2.51 ton/ha in the regional yield trials conducted for 3 years from 2009 to 2011.

• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1465-1483
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• 2020

Evapotranspiration is a concept that includes the evaporation from soil and the transpiration from the plant leaf. It is an essential factor for monitoring water balance, drought, crop growth, and climate change. Actual evapotranspiration (AET) corresponds to the consumption of water from the land surface and the necessary amount of water for the land surface. Because the AET is derived from multiplying the crop coefficient by the reference evapotranspiration (ET0), an accurate calculation of the ET0 is required for the AET. To date, many efforts have been made for gridded ET0 to provide multiple products now. This study presents a comparison between the ET0 products such as FAO56-PM, LDAPS, PKNU-NMSC, and MODIS to find out which one is more suitable for the local-scale hydrological and agricultural applications in Korea, where the heterogeneity of the land surface is critical. In the experiment for the period between 2016 and 2019, the daily and 8-day products were compared with the in-situ observations by KMA. The analyses according to the station, year, month, and time-series showed that the PKNU-NMSC product with a successful optimization for Korea was superior to the others, yielding stable accuracy irrespective of space and time. Also, this paper showed the intrinsic characteristics of the FAO56-PM, LDAPS, and MODIS ET0 products that could be informative for other researchers.