• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.264-271
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• 2002

Nitrogen releasing characteristics of polymer-coated urea(PCU) that made acrylic synthetic resins were studied in incubated soil, water and paddy soil. Also, their correlations and degradation patterns of coating material were tested. Releasing rate of nitrogen from PCU decreased with increasing coating rate. N001(coating rate 8.5%) and N003(coasting rater 6.3%) were low releasing amount at the early stage, whereas N005(coating rate 4.8%) was released over 80% within 20 days. Relationship of the releasing rate between incubated soil($25^{\circ}C$) and paddy soil could be described as follows : $Y=-0.0011X^2+2.2931X-50.264(R^2=0.9884)$ for N001, $Y=-0.0016X^2+1.1587X+5.5064(R^2=0.9805)$ for N003 and $Y=-0.03X^2+6.499X-243.22(R^2=0.9422)$ for N005, respectively (Y: release rate at field condition, X: experiment period). Relationship of the releasing rate between incubated water($30^{\circ}C$) and paddy soil can be described as follows : $Y=0.0011X^2+2.2601X-25.329(R^2=0.9884)$ for N001, $Y=-0.0306X^2+4.4994X-76.307(R^2=0.955)$ for N003 and $Y=-0.0164X^2+3.7764X-108.22(R^2=0.9422)$ for N005. After 150 days, coating materials of N001, N003, and N005 in incubated soil were degraded approximately 23%, 22% and 15%, respectively. Also The scanning electron microscope examination of coating material revealed that particle surface became gradually shattered with the time after the soil treatment.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 1993.12a
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• pp.6-9
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• 1993

According to changes in population, economic conditions, life-stile and eating habits, the frui ts and vegetables market wi 11 be shi fted from processed (i. e. , canned) to fresh. Undressed fresh produce, consisting of washed, disinfected and peeled fruits and vegetables that either sliced or grated, are currently increased in demand by retail and institutional market which use them as salad components or in ready-to use foods, Main attributes of minimally processed fruits and vegetables are convenience and fresh-like quality. Minimally processed Products readily deteriorate in quality, especially color and texture, as a result of endogeneous enzyme enhanced respiration and microorganisms which lead to reduced shelf Iife. According to changes in population, economic conditions, life-stile and eating habits, the frui ts and vegetables market wi 11 be shi fted from processed (i. e. , canned) to fresh. Undressed fresh produce, consisting of washed, disinfected and peeled fruits and vegetables that either sliced or grated, are currently increased in demand by retail and institutional market which use them as salad components or in ready-to use foods, Main attributes of minimally processed fruits and vegetables are convenience and fresh-like quality. Minimally processed Products readily deteriorate in quality, especially color and texture, as a result of endogeneous enzyme enhanced respiration and microorganisms which lead to reduced shelf Iife. Thus. to prevent these undesirable changes , val'ious techniques such as controlled atmosphere (CA) storage, modified atmosphere OIA) storage, including vacuum packaging have been receiving considerable attention, Although milch research has been done to find optimal conditions for whole intact frui ts and vegetables, only limi ted information is avai lable on fresh cut. and other minimally processed products. 81 iced frui ts exhibi t increas~d ethylene production and respiration compal'ed to whole f, 'uits during distribution in response to tissue damage. As a result, accelerated senescence and enzymatic browning OCCUI', Recent l'esearch on minimally processed fl'uits and vegetables has mainly focused on methods to inhibit browning, due to ban on use of sulfur dioxide, In order to retard or prevent these physiological changes, val'ious al ternatives, reducing agents. acidulants, chelating agents and inol'ganic sal ts have been evaluated for use on fresh cut fl'ui ts. Al though some agents were effective replacement for sulfur dioxide. consum$\textregistered$I'S demandless use of chemical on such products. Shel~ life of minimally processed products has been extended by inhibition of metabolic reactions associated with loss of quality and by inhibition of aerobic spoilage caused by wide variety of microorganisms. Appl ication of ~I.-\ packaging, including vacuum packaging, retards the rate of respiration, prevents growth of aerobic spoilage organisms, inhibits oxidation and color deterioration. Tissue softening is another major problem in minimally processed products because enzymes re 1 a ted to ce 11 wa 11 degrada t i on are not inactivated. Various treatments have been investigated for retardation of the softening of sliced products. Some studies have concentrated on the application of an active packaging system with ~I, l. packaging and calcium infi 1 tration as possible measures to retain firmness of processed products. In my opinion, one important step for production of minimally processed frui ts wi th favorabl e color of cut surface and firm texture is the selection of better cultivar. As the view, changing tendency of fresh color by apple cultivars and relationship between the tendency and PPO activity will be discussed in the seminar. In addition to the topic, research result on quality enhancement of fresh apple slices by heat shock treatment will be introduced.

• Journal of Bio-Environment Control
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• v.24 no.4
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• pp.275-280
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• 2015

The objective of this study was to investigate the effect of drip irrigation level on soil salinity and growth of broccoli (Brassica oleracea L. var. italica) at the 'Saemangeum Reclaimed Tidal Land' from April to June, 2015. Drip irrigation was conducted at 1.5, 3.0 and $6.0mm{\cdot}day^{-1}$ level for reduction of resalinization in the plastic vinyl house using 10cm spacing drip irrigation tape. At harvesting stage, the average EC of surface soil was $10.9dS{\cdot}m^{-1}$ for $1.5mm{\cdot}day^{-1}$, $11.5dS{\cdot}m^{-1}$ for $3.0mm{\cdot}day^{-1}$ and $5.1dS{\cdot}m^{-1}$ for $6.0mm{\cdot}day^{-1}$ and was significantly reduced by 52~56% in $6.0mm{\cdot}day^{-1}$ treated plot compared to those in 1.5 and $3.0mm{\cdot}day^{-1}$ plots. The fresh bud weights of 1.5, 3.0 and $6.0mm{\cdot}day^{-1}$ treatment plots were 60.9, 129.1 and $371.3g{\cdot}plant^{-1}$, respectively. The estimated soil EC for 50% yield reduction was $7.6dS{\cdot}m^{-1}$ and the desalinization depth by drip irrigation was 30~40cm in soil profile. The total amount of drip irrigation water was estimated to be 422mm and the daily drip irrigation level was $6.0mm{\cdot}day^{-1}$ for the prevention of resalinization during the broccoli growing period at the 'Saemangeum Reclaimed Tidal Land'. Our results suggested that drip irrigation shows effectiveness on the lowering the soil salinity according to the drip irrigation quantity but it needs more research on this study because dynamics of salts in soil can vary with many factors such as soil physico-chemical properties and seasonal climate.

• Korean Journal of Environmental Agriculture
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• v.37 no.1
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• pp.15-20
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• 2018

BACKGROUND: The global mean surface temperature change for the period of 2016~2035 relative to 1986~2005 is similar for the four representative concentration pathway (RCP)'s and will likely be in the range of $0.3^{\circ}C$ to $0.7^{\circ}C$. Climate change inducing higher temperature could affect not only crop growth and yield, but also dynamics of carbon in paddy field. METHODS AND RESULTS: This study was conducted to evaluate the effect of elevated temperature on the carbon dynamics in paddy soil and rice growth. In order to control the elevated temperatures, the experiments were set up as the small scale rectangular open top chambers (OTCs) of $1m(width){\times}1m(depth){\times}1m(height)$ (Type 1), $1 m(W){\times}1m(D){\times}1.2m(H)$ (Type 2), and $1m(W){\times}1m(D){\times}1.4m(H)$ (Type 3). The average temperatures of Type 1, Type 2, and Type 3 from July 15 to October 30 were higher than the ambient temperatures at $0.4^{\circ}C$, $0.5^{\circ}C$, and $0.9^{\circ}C$, respectively. For the experiment, Wagner's pots (1/2,000 area) were placed inside chambers. The pots were filled with loamy soil, and chemical fertilizer and organic compost were applied as recommended after soil test. The pots were flooded with agricultural water and rice (Shindongjin-byeo) was planted. It was observed that TOC (total organic carbon) of the water increased by the elevated temperatures and the trend continued until the late growth stage of the rice. Soil TOC contents were reduced by the elevated temperatures. C/N ratios of the rice plant decreased by the elevated temperature treatments. Thus, it was assumed that the elevated temperatures induced to decompose soil organic matter. Elevated temperatures significantly increased the culm length (P<0.01) and culm weight (P<0.05) of rice, but the number and weight of rice panicle did not showed significant differences. CONCLUSION: Based on the results, it was suggested that the elevated temperatures had an effect on changes of soil and water carbons under the possible future climate change environment.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.2
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• pp.65-72
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• 2006

Objective of this research was to remove the accumulated salts in the plastic film house soils by installing the perforated PVC (${\phi}10cm$) underdrainage pipes at 50 cm depth of soils with cultivating vegetables. Efficiency of the underdrainage pipes was assessed based on the changes of soil chemical properties such as pH, EC, and cations, and growth and yield parameters of the vegetables between the two treatments; the control and the underdrainage pipe treatments. The EC of the underdrainage pipes installed soils after two growing seasons were in the ranges of $1.42-2.88dS\;m^{-1}$ but those of the control were in the ranges of $3.86-4.53dS\;m^{-1}$, indication the underdrainage pipes effectively removed the accumulated salts in soils. The pHs of the control soils and the underdrainage pipe installed soil were in the ranges of 7.2-7.5 and 6.9-7.3, respectively. There was a significant correlation between pH and cation exchange capacity (CEC) of the soils ($CEC=17.107{\times}pH-106.2$, $r^2=0.759$, P < 0.05). The ECs of the soils at different depths were compared between the two treatments after cultivating vegetables with lettuce-lettuce-garland chrysanthemum rotation systems. The ECs of the control soils at depths of 0-10, 10-20, 20-30, 30-40, and 40-50 cm were 3.45, 3.47, 3.03, 2.03, and $2.28dS\;m^{-1}$, respectively, with decreasing with soil depths. On the other hand, the respective ECs of the underdrainage pipes installed soils were 2.43, 2.52, 2.28, 4.00, and $4.23dS\;m^{-1}$ with increasing with soil depths. This might be derived from the salts moved downward with the draining water into the subsoil. The order of cations moved downward was Mg > Ca > K, based on the ratios of cations at specific depth over those at the surface soil. The survival rates of lettuce after 15 days of transplanting in the underdrainage pipe installed soils were 98.2% as compared to 86.6% of the control. The underdrainage pipe treatment also increased the diameter of the lettuce stalk from 12.9mm of the control to 13.7mm. Overall results demonstrated that the installment of the underdrainage pipes in the subsoils of the salt accumulated plastic film house soil effectively removed the salts by leaching downward,resulting in lowering soil EC and enhancing the growth and yield of vegetables.

• Korean Journal of Heritage: History & Science
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• v.52 no.3
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• pp.74-93
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• 2019

The Bird Track Site in the Haman Formation in Yongsanri (Natural Monument No. 222) was reported on the named Koreanaornis hamanensis and Jindongornipes kimi sauropod footprint Brontopodus and ichnospecies Ochlichnus formed by Nematoda. This site has outstanding academic value because it is where the second-highest number of bird tracks have been reported in the world. However, only 25% of the site remains after being designated a natural monument in 1969. This is due to artificial damage caused by worldwide fame and quarrying for flat stone used in Korean floor heating systems. The Haman Formation, including this fossil site, has lithofacies showing reddish-grey siltstone and black shale, alternately. The boundary of the two rocks is progressive, and sedimentary structures like ripple marks and sun cracks can clearly be found. This site was divided into seven formations according to sedimentary sequences and structures. The results of a nondestructive deterioration evaluation showed that chemical and biological damage rates were very low for all formations. Also, physical damage displayed low rates with 0.49% on exfoliation, 0.04% on blistering, 0.28% on break-out; however, the joint crack index was high, 6.20. Additionally, efflorescence was observed on outcrops at the backside and the northwestern side. Physical properties measured by an indirect ultrasonic analysis were found to be moderately weathered (MW). Above all, the southeastern side was much fresher, though some areas around the column of protection facility appeared more weathered. Furthermore, five kinds of discontinuity surface can be found at this site, with the bedding plane showing the higher share. There is the possibility of toppling failure occurring at this site but stable on plane and wedge failure by means of stereographic projection. We concluded that the overall level of deterioration and stability were relatively fine. However, continuous monitoring and conservation treatment and management should be performed as situations such as the physicochemical weathering of the fossil layer, and the efflorescence of the mortar adjoining the protection facility's column appear to be challenging to control.

• Korean Journal of Heritage: History & Science
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• v.55 no.1
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• pp.305-321
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• 2022

The stone chamber tomb in Eungpyeong-ri, Buyeo, is a joint tomb that contains the bodies of two individuals. This paper investigates the relationship between the buried persons and the characteristics of the stone chamber tomb. Based on the geographical location, relics, and the excavated human bones, it was determined that the tomb was built during the Sabi Period of the Baekje Dynasty and that the buried individuals were most probably residents of high stature or government officials. To study the excavated bones, the remains were carefully collected and conservation was carried out. Before collecting samples from the human bones for the analytical research, the results of near-infrared analysis were used to collect the samples for the isotope analysis and DNA analysis. The most important issue when handling the excavation site was the reinforcing agent and the concentration of the agent used. In situations like this, Paraloid B-72 is the most suitable agent. When the shape of human bones was difficult to distinguish from the soil, conservation was performed using X-ray and CT imaging data. The same chemical used for the reinforcement of the site was used to complete a minimum level of conservation to the surface areas where the conservation treatment of removing foreign substances, the reinforcement areas, and bonded areas were carried out. The collagen yield from the sample obtained at selected position was 3.8% to 6.1%. The results of analyzing the stable isotopes of carbon and nitrogen found in the extracted collagen showed that the stable isotope ratios came out to δ¹³C -18.3‰±0.1‰, -19.0‰±0.1‰ for EBW and δ¹⁵N 10.7‰±0.5‰, 10.6‰±0.1‰ for EBE. It is believed the two individuals consumed small amounts of minor cereals, mainly from C₃ plants, and protein was obtained from eating terrestrial animals. What's more, the deviations in data obtained from the two individuals were so small that it could be inferred that the individuals ate similar foods. Considering the preservation state of the sample, amplifying DNA for the DNA analysis would have been very difficult since the amount of surviving DNA was so deficient. For DNA analysis, it is anticipated that the results could be derived by applying improved extraction methods that will be developed in the future. In this research, any association between scientific analysis(DNA and stable isotope ratio) and near-infrared spectroscopy was difficult to establish. Further research is needed on the utilization of near-infrared analysis for gathering samples from human bones.

• Journal of Korean Society of Forest Science
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• v.19 no.1
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• pp.1-23
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• 1973

The results of ground vegetation experiment conducted at completely denuded forestland in the mudstone region are summerized as follows: On the reaults of soiling quantity the effect of soiling was observed where depth of soiling over 10 cm was practiced, and a plot where treated with 15cm soiling and without fertilizer showed poor growth and it was even worser than the plot where soiling was practiced only 1 cm in thikness but applied adequate amount of fertilizers. The depth of slits between 30cm and 40cm showed no significant difference in the effect. A plot where covered with vegetation bag showed somewhat better results in seed loss and early growth but no differences observed in the fall result over the none covered plot. And then, it is recommendable to have soiling over 10cm in thikness with slit of 30cm and 30cm in depth and to apply 30 gram of fertilizer (22;22:11, 50 gram) per slit. On various soiling materials trial there were no striking differences in the effect of soiling between weathered granite soil, wheathered tuffs soil and weathered mudstone soil. In the treatment with various green materials, a plot treated with straw mat showed a significant difference at 1 percent. The results show that weathered mudstone soil is effective to use as soiling materials and straw mat treatment was better. On forest fertilization trial, in the mudstone region where red and black pine trees already existing at a rate of 2,000-3,000 trees per hectare had applied 110kg of compound fertilizers (9:12:3 and 22:22:11) per hectare basis in terms of plant nutrient. As a result, the difference in effect between the compound fertilizers was not found however the leaf color and leaf length of the fertilizer added plot showed darker and longer at 30 percent over the no fertilizer received plot. Compound fertilizers, 14:37:12 and 9:12:3 were applied to alder trees at a rate of 20 gram and 40 gram per tree in terms of plant nutrient and a remarkable growth accelerantion was observed where 40 grams of plant nutrient applied. The effect difference between the compound fertilizers was not found. On investigation of tree root elongation, forty years old red pine trees showed only 15cm tap root elongation through mudstone while black pine had 23 cm tap root elongation. The total length of supporting root elongtion of red and black pines showed 20 and 13 meters, respectively. The tap roots of Black locusts were not able to elongate through mudstone, however, the supporting roots tended to develop to the underneath of pine tree where some moisture content is available. Black locusts And grown on the residual soil of mudstone normally die between 8 to 10 years. The red pine trees show flat in tree shape while black pine had triangle in the shape. With the results it can be said that in an artificial reforestation in denuded forest land of the mudstone region the adequate slit and enough amount of fertiliizer application must be provided for the succesful performance of the program. On integrated experimental results of 1972. for the establishment of ground vegetation on the completely denuded forest land in mudstone region, soiling could be effectively practiced with weathered mudstone soil and it would not specially necessiate to have either weathered granite or tuffssoil for the soiling. And the soiling depth should be more than 10 cm in thickness. Among green materials used the straw mat proved to be the most effective reatment. Three major factors which enable to establish ground vegetation by the shortest period of time: A. Physical improvement of soil is necessary to breakdown of the horizontal cracks sushas Slit, contour line plot, seeding hole and etc., and soiling with weathered mudstone soil. B. Chemical improvement of soil: is needed sufficient amount of fertilizer application 300~400kg ha, $N+P_2O_5+K_2O$), and increased production of ground covering and expedite resolution of the vegetation (ground vegetation, fallen leaves and twigs). C. Complete establishment of the basic structure for the erosion control (Prevention of surface soil erosion)