• Korean Journal of Soil Science and Fertilizer
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• v.40 no.2
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• pp.145-150
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• 2007

This study was conducted to evaluate the application effects of phospho-gypsum fertilizer (PGF) as reclamation material in the newly reclaimed paddy fields located in Goheung and Youngam, Jeonnam province in Korea. The PGF used in this experiment was produced by Namhae Chemical Co. as the name of Soil-Saver$^{TM}$. Prior to rice transplanting, the PGF was applied as soil amendment as the amount of $3,000kg\;ha^{-1}$. The PGF increases rice plant height and number of tiller at the heading stage by 119.9 cm and 9.1, respectively, in Youngam area. The harvest index of brown rice increased up to 5 and 13% more in the PGF applied paddy field from both sites than in the non-application of PGF at paddy field before rice transplanting, and the ripening ratio in increased in both sites to 81 and 90%. Protein content of brown rice was also greater than in the non-application of PGF at the both sites. For the effects of the reclamation by PGF in the paddy field soils, we found that PGF reduced exchangeable Na to 18 and 28% for both sites, respectively, and increased exchangeable Ca and $SO_4$. And we found relatively higher amounts of $K_2O$, CaO and MgO in the rice plants from both sites applied with PGF.

• Atmosphere
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• v.31 no.3
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• pp.267-282
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• 2021

Characteristics of carbonaceous components and organic compounds in PM_2.5 over the atmosphere of the Yellow Sea were investigated. PM_2.5 samples were collected onboard the meteorological research vessel, GISANG 1, over the Yellow Sea during the YES-AQ campaign in 2018 and 2019, respectively. The average concentrations of carbonaceous components in this region were 2.59 ± 1.59 ㎍ m^-3 for the OC, 0.24 ± 0.10 ㎍ m^-3 for the EC, 2.14 ± 1.30 ㎍ m^-3 for the WSOC and 1.17 ± 0.94 ㎍ m^-3 for the HULIS-C, respectively. The total concentration of 56 organic compounds (ΣOCs) accounts for 10% of OC. The main group among organic compounds were dicarboxylic acids which account for 57% of ΣOCs, followed by n-alkanoic acids accounting for 34% of ΣOCs. In n-alkanoic acid distribution, hexanoic (C_6:0) and octanoic (C_8:0) acids which are low molecular weight n-alkanoic acids and known as emitted from marine biogenic activities were dominant in this region. Furthermore, non-HULIS-C fraction increased when the air mass originated from the marine region rather than the continental region. When the Asian dust episode was observed, the WISOC concentrations along with the levoglucosan were increased, while the haze episodes caused the increase of WSOC, HULIC-S and DCAs. In this study, we found that the components of carbonaceous and organic aerosols in PM_2.5 over the Yellow Sea were changed with the specific air pollution episodes. It indicates that the physicochemical properties of PM_2.5 can be changed by the air pollution episodes in this region.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.431-448
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• 2021

We decided the efficient application timings of organo-synthetic insecticides for controlling the first generation larvae of O. furnacalis through investigations of insect stage-specific densities, damage aspects in maize, and effects of insecticides. A waxy maize cultivar, Ilmichal, was cultivated from April 20 (sowing) to July 26 (harvest, dough stage of maize) in Suwon, 2016. The maximum and 50% cumulative catch dates of the overwintering generation adults in the sex pheromone trapping were May 29 and May 31, respectively. Most of the first generation larvae finished their occurrence till the early reproductive stage of maize. The first generation larvae fed on leaves inside the whorl leaves before tassel and stem development of maize, sequentially moved to tassel and stem, and then moved finally to stem and ear parts. In the results of insecticide applications at different dates, the 9-11 leaf stage (June 10~17) and the 6-7 leaf stage (June 3) of maize were the most efficient application timings for direct spray of Etofenprox EC to maize, and for application of Carbofuran granules onto soil surface, respectively, which resulted in suppression of tunnelling damages. The timings for the two insecticides were 12-19 days and 5 days after the adult maximum catch date, respectively. Those timings after the 50% cumulative adult catch date were advanced 2 days.

• Journal of Bio-Environment Control
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• v.30 no.3
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• pp.244-249
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• 2021

The hydroponic culture for growing 'Duke' blueberry was evaluated in a protective greenhouse provided with similar environmental conditions to the conventional blueberry cultivations. One year old 'Duke' blueberry bushes planted in 180 L containers filled with 130 L peat moss and 40 L pearlite (v/v) were selected for the experiment. A nutrient solution consisted with NO₃-N 4.6, NH₄-N 3.4, PO₄-P 3.3, K 3, Ca 4.6, and Mg 2.2 mmol^-1 was supplied to the plants, comparing non-hydroponic treatment (provided with only underground water). Hydroponic culture increased number of shoot per bush by 18% and total shoot length by 24% compared with non-hydroponic culture. Total dry weight of a bush increased in the hydroponic with vigorous root growth 1.4-fold more than the non-hydroponic. Higher concentrations of inorganic elements and organic compounds were found in the hydroponic, indicating active nutrient absorption of the bush. The hydroponic produced high yield similar to adult bush from 4 years old age, maintaining the yield until 8 years old age. The findings of this study indicated that hydroponic cultivation systems will be useful for growing blueberry crop.

• Journal of Physiology & Pathology in Korean Medicine
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• v.33 no.2
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• pp.131-140
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• 2019

The objective of present study is to evaluate concentration-dependent in vitro anti-osteoarthritic (OA) effects of synergic mixed formula consisted of dried pomegranate juice concentrate powder, Eucommiae Cortex aqueous extract and Achyranthis Radix aqueous extract 5:4:1 (g/g) mixture on the primary cultured rat articular chondrocytes. First, any cytotoxic effect of mixture was observed using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium Bromide) assay. Next, cyto-protective effect of test substances was evaluated by using the recombinant human interleukin $(rhIL)-1{\alpha}$ induced chondrocytes. In addition, anti-inflammatory effects were also observed on the lipopolysaccaride (LPS) treated chondrocytes through prostaglandin $E_2(PGE_2)$ productions and 5-lipoxygenase (LPO) activities, and inhibitory effects on matrix metalloproteinase (MMP)-2 and MMP-9 activities were observed on $rhIL-1{\alpha}$ treated chondrocytes with their extracellular matrix (ECM) related mRNA expressions. No obvious cytotoxic effects of mixture were demonstrated. Inflammatory damages of chondrocytes and related ECM degradations induced by treatment of LPS or $rhIL-1{\alpha}$ were significantly and concentration-dependently inhibited by pretreatment of mixture from a concentration level of 0.001 mg/ml to 1 mg/ml. In addition, mixture showed $IC_{50}$ for $rhIL-1{\alpha}-induced$ MMP-2 and MMP-9 activities as 44.01 and $162.47{\mu}g/ml$, and also showed $EC_{50}$ for $rhIL-1{\alpha}-induced$ inhibition of collagen type II, SOX9 and aggrecan mRNA expression as 8.61, 10.79 and $4.47{\mu}g/ml$, respectively. It is observed that mixture showed concentration-dependent anti-inflammatory and cytoprotective ECM preserved effects on the primary cultured rat articular chondrocytes without cytotoxicity.

• Korean Journal of Environmental Agriculture
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• v.38 no.3
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• pp.124-132
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• 2019

BACKGROUND: Silver grass (Miscanthus sinensis) No. 1 was developed for production of bio-ethanol, and for the purpose the silver grass growing sector was established in Geumgang basin, Iksan, Jeonbuk, in 2011. However, the other application potentials except for using as the bio-energy resources should be considered because of the drop in international oil prices. Therefore, there is the necessity of a scientific basis to use the silver grass instead of rice straw as the organic matter source that is used for improvement of soil quality in the plastic film house. METHODS AND RESULTS: The silver grass was applied at 5, 10, 15 and 20 Mg/ha and tilled before the watermelon was planted in the plastic film-house. The control plot was treated with 10 Mg/ha with rice straw, and watermelons have been cultivated for 3 years(2017~2019). Soil aggregation, soil chemistry, and the growth characteristics were investigated, when the watermelon was harvested every year. Soil aggregation levels at the 2nd and 3rd year of watermelon harvest were similar from the plot applied with the silver grass at 5 Mg/ha and the control plot, and increased in the silver grass treated plots with more than 10 Mg/ha. However, there was no statistically significant difference between the plots. The nitrogen mineralization of silver grass in the control plot tended to be similar to the 5 Mg/ha plot, but the silver grass treated plots with over 10 Mg/ha showed low nitrogen mineralization. Soil EC on harvest stage was proportional to the applied mass of the silver grass, but pH was in inverse with the applied mass. Soil organic matter content, available phosphate, and exchangeable cations increased with the continued use of silver grass. Watermelon weight found to be the best on more than 15 Mg/ha of silver grass, and the sugar content was highest when 10 Mg/ha was treated. CONCLUSION: The use of the silver grass at 10 Mg/ha annually as the organic source was effective in replacing rice straw while growing fruits and vegetables on the plastic film house.

• Journal of Environmental Science International
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• v.28 no.9
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• pp.729-735
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• 2019

The aim of this study was to determine the effects of different compositions of environmental substrates on hydroponic tomato cultivation. Three different substrates were used in coir chip:dust (v/v=50:50; CP1), coir chip:dust (v/v=80:20; CP2), and rock wool cube with CP2 (CPR). The amount of irrigation during the cultivation period was 190 mL/(plant time) in all substrates. The pH and EC were 5.8-6.2 and 2.6-2.9 dS/m, respectively. The drainage rate in CP1 was 31%, in CP2 was 36%, and in CPR was 29%. The growth of tomato plants in terms of height was higher in CP1 and CPR. The leaf area was greater in CP2. The fresh and dry weights were greater in CP2 and CPR treatments. The net photosynthesis in CP2 ($19.31{\mu}mol\;CO_2/m^2s$) and root activity in CP2 were higher among all three treatments. The soluble solid content of fruit was not significantly different among treatments. The yield per plant in CP2 and CPR treatments was 17% greater than the yield per plant in CP1. Therefore, the most suitable substrate for hydroponic tomato cultivation is the substrate mixed with coir chip:dust (v:v=80:20; CP2), i.e., CPR.

• Korean Journal of Environmental Agriculture
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• v.38 no.3
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• pp.119-123
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• 2019

BACKGROUND: Estimation of soil nitrogen supply is essential to manage nitrogen fertilization in arable land. In Korea, nitrogen fertilization is recommended based on the soil organic matter content because it is difficult to assess nitrogen (N) mineralization of upland soils directly. In this study, the relationship between soil organic matter (SOM) content and N mineralization was investigated to explore the limitation of using SOM in predicting soil N mineralization. METHODS AND RESULTS: Soil samples from the 0 to 10 cm depth were collected from 18 individual pepper cultivated fields in Tae-an and Chung-yang provinces before fertilization. N mineralization in the soils was quantified using incubation for 70 days at $30^{\circ}C$. The mineralizable soil N (MSN) was positively correlated with SOM, and the relation equation between MSN and SOM was '$MSN(kg\;10a^{-1})=0.2933{\ast}SOM(g\;kg^{-1})+0.0897$ ($r^2=0.6224$, p<0.001)'. However, the differences of N mineralization among the soils with the similar concentrations of soil organic matter were about 3 to 4.6 times, suggesting that the other soil factors such as total N concentration or EC should affect N mineralization. CONCLUSION: We concluded that SOM alone could not reflect the capacity of soil to supply N that is used for recommendation of N fertilization rate. Therefore, other soil properties should be considered to improve N fertilization management in arable land for sustainable agriculture.

• Health Policy and Management
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• v.29 no.1
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• pp.4-10
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• 2019

The term new tobacco products (NTPs) refers to the new alternatives to conventional cigarettes. There are several kinds of NTPs in South Korea. The present study discusses the most widely used NTPs namely electronic cigarette (ECs) and heated tobacco products (HTPs). The aims of this study are to evaluate the risk related to the use of ECs and HTPs, introduce policy examples across different countries of management of this issue, and finally, present some policy implications of the problem and our response strategies. Since the advent of ECs, there has been a lot of debate about its risk. Some studies have reported that ECs are less harmful than conventional cigarettes and that they are effective in aiding smoking cessation. Nevertheless, the efficacy of ECs in smoking cessation and its potential health risks are still unclear. However, the obvious fact is that it is not harmless. Regulations on ECs differ from country to country. In many countries, they are strictly regulated as tobacco or toxic substances; however, in the United Kingdom, the use of ECs are included as part of their smoking cessation policy, and in Japan, they are treated as a form of medication. On the other hand, HTPs are the most recently introduced NTPs and they have attained sensational popularity because of the wrongly held belief that they are less harmful to health. So, what about our policy response to these two tobacco products? The research on ECs requires more systematic statistical monitoring, such as monitoring the ratio of dual-users. Further, the new EC smokers should be identified taking into account that the arguments for the use of ECs often emphasize smoking cessation or less risks to health, the government should further strengthen its policy to prevent those claims. The HTPs market experienced a very sharp growth and continues to grow because the government policy is too passive. Taking this as a lesson, it is necessary to approach NTPs, such as HTPs, proactively and increase their contribution to the National Health Promotion Fund by imposing greater taxes on them. Finally, considering the likelihood of NTPs being promoted as a less harmful tobacco product, it is essential to strictly regulate tobacco companies' publicity from the very beginning to ensure that potential consumer s are not mislead.

• Journal of Environmental Science International
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• v.28 no.3
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• pp.303-320
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• 2019

Water quality is characterized by various complex factors. Therefore, a systematic understanding of water quality trends is required to carry out a proper evaluation. In this study, we analyzed the spatio-temporal water quality characteristics of the Nakdong River using five-year data from 2012 to 2016. Data was collected on the pH, DO, BOD, COD, SS, TN, TP, TOC, WT, EC, $NH_3-N$, $NO_3-N$, $PO_4-P$, Chl-a, rainfall, and total and fecal coliforms. A total of 38 water quality measurement stations, from Andong1 to Gupo, were considered. Statistical analyses including trend, cluster, and factor analyses were conducted to identify the dominant water quality components affecting the Nakdong River. The Nakdong River was spatially classified into three groups for up-stream (Andong1 to Sangju1), mid/up-stream (Donam to Dalseong), and mid/down-stream (Hwawonnaru to Gupo) data collection, and temporally into two groups for summer/fall (7~10), and the rest of the season (11~6) data. The water quality of the entire Nakdong River showed trends similar to the mid/down-stream section, which indicates the importance of water quality management in this section. Suspended solids, phosphorus, and coliform groups were established as important factors to be considered in the summer/fall season across the river, especially in the mid/down-stream section. Nitrogen and organic matter were identified as important factors to be considered in the rest of the season, especially in the mid/up-stream section. This study could help determine the water quality components that should be intensively monitored in the Nakdong River.