• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.110-116
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• 2019

This study was conducted to determine the effects of a pre-planting fertilizers with various $NH_4{^+}:NO_3{^-}$ ratios in a coir dust:peatmoss:perlite (3.5:3.5:3.0, v/v/v) medium on the growth of hot pepper (Capsicum annuum L. cv. Nokkwang) plug seedling. Nitrogen levels were fixed to $300mg{\cdot}L^{-1}$ and the $NH_4{^+}:NO_3{^-}$ ratios were varied to 0:100, 27:73, 50:50, 73:27, and 100:0. The 50-cell trays were filled with treatment media containing pre-plant fertilizers, then seeds were sown. After seeds were germinated, the trays were moved to greenhouse and seedlings were feed with 13-2-13 and 20-9-20 fertilizers, alternatively. The changes in pH and EC were measured every week and soil solution for nutrient concentrations were analyzed in week 0, 3, and 7. The measurements of seedling growths as well as analysis of tissue nutrient contents were also conducted in week 7. The varied $NH_4{^+}:NO_3{^-}$ ratios did not influence on the pHs of root media after incorporation of pre-planting fertilizers, but the ECs were heightened as proportion of $NH_4{^+}$ to $NO_3{^-}$ were elevated. During the raising of seedlings, the pHs rose over time in the treatments of 0:100 and 27:73 ($NH_4{^+}:NO_3{^-}$). The concentrations of all macro-elements in root media decreased gradually as seedlings grew in all treatments. The seedling growths 7 weeks after seed sowing were the highest in the treatments of 27:73 and 50:50 ($NH_4{^+}:NO_3{^-}$) and those became worse in the treatments of higher $NH_4{^+}$ ratios than 73%. In terms of inorganic element contents based on the dry weight of above ground tissue, the treatment of 0:100 showed the lowest content of Ca, Mg, Na, Cu, Mn, and Zn. Based on the results, it is desired that $NH_4{^+}$ ratio in pre-planting fertilization is maintained to be 50% or less for the raising of hot pepper plug seedlings.

• 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 Bio-Environment Control
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• v.32 no.3
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• pp.249-255
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• 2023

Korean melon (Cucumis melo L.) is grown mostly in Northeast Asia area, and as a fruit mainly produced in Korea, the yield per unit area continues to improve, but the cultivation method is limited to soil cultivation, so it is necessary to develop hydroponic cultivation technology for scale and labor-saving is needed. As the ratio of NO₃^- increased, the plant height, the leaf length, the leaf width, and the internode length became longer and larger. On the other hand, the SPAD value decreased. The lower the ratio of NO₃^-, the faster the female flower bloom, and there was no difference in fruit maturity between treatments. There was no difference in the shape of fruit according to the ratio of NO₃^-, and the hardness was higher as the ratio of NO₃^- was lower. The total yield from March to July was KM3 5,650 kg/10a and KM1 4,439 kg/10a, 27% higher in KM3 and, in particular, 36% higher in quantity from March to May, when Korean melon prices were high season. Therefore, it was judged that it would be appropriate to supply NO₃^- suitable for hydroponic cultivation of Korean melon, which was formalized in December and produced from spring, at the level of 6.5 to 10 me·L^-1.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.306-314
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• 2023

Stream sediments are an important component of water quality management because they are receptors of various pollutants such as heavy metals and organic matters emitted from upland sources and can be secondary pollution sources, adversely affecting water environment. To effectively manage the stream sediments, identification of primary sources of sediment contamination and source-associated control strategies will be required. We evaluated the performance of machine learning models in identifying primary sources of sediment contamination based on the physico-chemical properties of stream sediments. A total of 356 stream sediment data sets of 18 quality parameters including 10 heavy metal species(Cd, Cu, Pb, Ni, As, Zn, Cr, Hg, Li, and Al), 3 soil parameters(clay, silt, and sand fractions), and 5 water quality parameters(water content, loss on ignition, total organic carbon, total nitrogen, and total phosphorous) were collected near abandoned metal mines and industrial complexes across the four major river basins in Korea. Two machine learning algorithms, linear discriminant analysis (LDA) and support vector machine (SVM) classifiers were used to classify the sediments into four cases of different combinations of the sampling period and locations (i.e., mine in dry season, mine in wet season, industrial complex in dry season, and　industrial complex in wet season). Both models showed good performance in the classification, with SVM outperformed LDA; the accuracy values of LDA and SVM were 79.5% and 88.1%, respectively. An SVM ensemble model was used for multi-label classification of the multiple contamination sources inlcuding landuses in the upland areas within 1 km radius from the sampling sites. The results showed that the multi-label classifier was comparable performance with sinlgle-label SVM in classifying mines and industrial complexes, but was less accurate in classifying dominant land uses (50~60%). The poor performance of the multi-label SVM is likely due to the overfitting caused by small data sets compared to the complexity of the model. A larger data set might increase the performance of the machine learning models in identifying contamination sources.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.1
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• pp.34-48
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• 1982

1. Production and consumption of chemical fertilizers in Korea could be divided into five different phases of total imports, setting up fertilizer plants, self-sufficiency in production, net export, and diversification in compound fertilizers. Currently the nation has production capacity of 800 thousand M/T of nitrogen, 400 thousand M/T of phosphate ($P_2O_5$) and 200 thousand M/T of potash ($K_2O$). 2. Yearly consumption increased every year, since 1964, 28,000 M/T N, 7,700 M/T $P_2O_5$, and 7,500 M/T $K_2O$ until 1972, when the increase jumped by eight times for $P_2O_5$ and seven times for $K_2O$ for the following 3 years in anticipation of their short supply. Now total consumption has been more or less stabilized at the level of 450 thousand M/T N, 220 thousand M/T $P_2O_5$ and 180 thousand M/T $K_2O$ for the last 7 years. 3. Current operation rate of fertilizer plants is around 80% throughout the whole industry, after going through several different levels depending on demand at times. 4. Fertilizer export started in 1967 and reached a peak of 150 thousand nutrient ton in 1972, about 20% of total production, before temporarily stopping due to over-demand for next three years. The export resumed again in 1976 rise to the all time high of 670 thousand nutrient ton in 1980, almost half of total production, and then started to decline due to higher price of petroleum since then. 5. The decline in fertilizer export appears to be accelerated because several countries, in South-Eastern Asia, traditional export market for Korean fertilizers, started to build their own plants, since 1980, based on their raw materials of especially petroleum. 6. Current consumption in Korea is about 30 nutrient Kg per 10a, equivalent to that in Western European countries, partly due to new high-yielding rice varieties and extensive cultivation of fruit trees and vegetables. Additional fertilizer demand in future can be anticipated in reclaimed land for growing grass and forestry.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.3
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• pp.200-206
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• 1985

This field experiment was undertaken to assess the effects of three levels of inclination ($10^{\circ},\;20^{\circ},\;and\;30^{\circ}$) and four rates of $N-P_2O_5-K_2O$ (0-0-0-, 14-10-10, 28-25-25, and 42-40-40kg/10a) on establishment, yield and quality, and botanical compositions of mixed grass-clover sward. This second part is concerned with the soil chemical properties, concentrations and uptake of mineral nutrients, and percent recovery and efficiency of NPK. The results obtained after a two-year experiment are summarized as follows: 1. The pH, exchangeable Mg and Na, and base saturation in the surface soils were decreased by increasing the grade of inclination, whereas organic matter and available $P_2O_5$ tended to be increased. However, the changes in the Ca content and equivalent ratio of $K\sqrt{Ca+Mg}$ were not significant. The pH, exchangeable Ca and Mg, and base saturation were reduced by increasing the NPK rate, whereas available $P_2O_5$, exchangeable K, and equivalent ratio of $K\sqrt{Ca+Mg}$ tended to be increased. 2. The concentrations of mineral nutrients in grasses and weeds were not significantly affected by increasing the grade of slope in hilly pasture, whereas the concentrations of N, K, and Mg in legume were the lowest with the steep slope, which seemed to be related to the low legume yield. The Mg concentrations of all forage species were below the critical level for good forage growth and likelihood of grass tetany. 3. The increase of NPK rate resulted in the increment of N, K and Na concentrations, and the decrease of Mg and Ca in grasses. The P concentration was increased with P application, but there were no differences in that among the P rates applied. It resulted also in a slight increase of K, and a decrease of Mg in legume, but the contents of N, Ca, and Na were not affected by that. On the other hand, it has not affected the mineral contents in weeds except a somewhat increase of N. The mixed forages showed a increase of N and K contents, a decrease of Ca and Mg, and a slight change in P and Na. 4. The percent recovery of N, P and K by mixed forages were greatly decreased by increasing the grade of inclination and NPK rate. They were high in the order; K>N>P. The efficiency of mixed NPK applications was decreased by that. The efficiency of mixed NPK fertilizers absorbed was slightly decreased by the increased rate of NPK, but it was not affected by the grade of inclination.