• Journal of Bio-Environment Control
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• v.30 no.1
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• pp.56-64
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• 2021

This study was conducted to examine the effect by different types and concentrations of auxin on the rooting and growth of strawberry (Fragaria × ananassa Duch. cv. Maehyang) cuttings in the greenhouse. The NAD (1-naphthylacetamide), IBA (indole-3-butyric acid), and IAA (3-indoleacetic acid) were applied with a 1 hour soaking as 50, 100, 150, and 200 mg·L-1, respectively. The non-treatment was set as the control. The cuttings of strawberry were transplanted in the strawberry seedling tray filled with coir medium on June 4, 2020. The humidification was carried out for 2 weeks. The average relative humidity, daytime temperature, and nighttime temperature inside the humidification tunnel was 63.4 ± 15%, 29.3 ± 5℃, and 16.2 ± 5℃, respectively. There was no significant difference in rooting rate on the control, IBA, and IAA treatments. However, significantly low rooting rates were observed in NAD treatments. The survival rates were significantly higher in the control and IBA with 50 mg·L-1 than in other treatments. The number of leaves was the highest in IBA with 100 mg·L-1. The root length was the longest in the control. More number of roots were counted in IAA with 100 and 150 mg·L-1. The dry weight of root was the heaviest in the control. The total root length, root surface, number of root tips, and number of root forks were significantly higher in the control. As a result, control, IAA, and IBA showed similar shoot and root growth. However, NAD showed the worst root and shoot growth. Consequently, compared with IAA and IBA, NAD was not appropriate plant growth regulator of rooting for cutting propagated strawberries.

• Journal of Bio-Environment Control
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• v.31 no.1
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• pp.67-76
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• 2022

This study aimed to determine the photosynthesis and growth characteristics of Peucedanum japonicum T. grown under aquaponics in a plant factory (AP) by comparing those grown under hydroponic cultivation system (HP). The AP system raised 30 fishes at a density of 10.6 kg·m^-3 in a 367.5 L tank, and at HP, nutrient solution was controlled with EC 1.3 dS·m^-1 and pH 6.5. The pH level ranged from 4.0 to 7.1 for the AP system and 4.0 to 7.4 for the HP system. The pH level in the AP began to decrease with an increase in nitrate nitrogen (NO₃-N) and lasted bellower than pH 5.5 for 15-67 DAT. It was found that ammonium nitrogen (NH₄-N) continued to increase even under low pH conditions. EC was maintained at 1.3 to 1.5 dS·m^-1 in both systems. The concentration of major mineral elements in the fish tank was higher than that of the hydroponics, except for K and Mg. There was no significant difference in the photosynthesis characteristics, but the PIABS parameters were 30.4% lower in the AP compared to the HP at the 34DAT and 12.0% lower at the 74DAT. There was no significant difference in the growth characteristics, but the petiole length was 56% longer in the leaf grown under the AP system. While there was no significant difference in the fresh and dry weights of leaf and root, the leaf area ratio was 36.43% higher in the AP system. All the integrated results suggest that aquaponics is a highly-sustainable farming to safely produce food by recycling agricultural by-products, and to produce Peucedanum japonicum as much as hydroponics under a proper fish density and pH level.

• Korean Journal of Organic Agriculture
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• v.16 no.1
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• pp.127-142
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• 2008

This study was carried out to germination characteristics by temperature conditions and allelopathic effects of aqueous extracts on Amaranthus spinosus L. in order to investigate the competitive dominant in plant ecosystem and possibility application of natural herbicide. A. spinosus L. sprouted after 24 hour from seeding in $30{\sim}45^{\circ}C$ treatment. The germination ratio of A. spinosus L. was the highest estimated at 63.3(${\pm}2.9$)% in $40^{\circ}C$ treatment, followed by 33.3(${\pm}2.9$)% in $35^{\circ}C$, 1.7(${\pm}2.9$)% in $30^{\circ}C$ and 5.0(${\pm}0.0$)% in $45^{\circ}C$ treatment. It was generally decreased the Relative Germination Ratio(RGR), the Relative Elongation Ratio(RER), the Relative Fresh weight Ratio(RFR) of receptor plants by the aqueous extracts of concentration of A. spinosus L. but it was differently inhibited the kind of receptor plant species. And it was different effected among growing regions that aqueous extracts of concentration of A. spinosus L. inhibited more root than shoot. The total phenolic compounds content of A. spinosus L. was decreased gradually middle, first and last of growth stage, and gradually decreased to leaves, roots and stems. We think that A. spinosus L. appeared high germination ratio at a short period and showed allelopathic effects on other plants. Therefore A. spinosus. L. hold the competitive dominant of plant ecosystem in Jeju Island and possibility application of natural herbicide.

• Microbiology and Biotechnology Letters
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• v.46 no.3
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• pp.253-260
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• 2018

Beneficial microorganisms are widely used in the forestry, livestock, and, in particular, agricultural sectors to control soilborne diseases and promote plant growth. However, the industrial utilization of these microorganisms is very limited, mainly due to uncertainty concerning their ability to colonize and persist in soil. In this study, the survival of beneficial microorganisms in field soil microcosms was investigated for 13 days using quantitative PCR with B. subtilis group-specific primers. Bacterial community dynamics of the treated soils were analyzed using 16S ribosomal RNA (rRNA) gene amplicon sequencing on the Illumina MiSeq platform. The average 16S rRNA gene copy number per g dry soil of Bacillus spp. was $4.37{\times}10^6$ after treatment, which was 1,000 times higher than that of the control. The gene copy number was generally maintained for a week and was reduced thereafter, but remained 100 times higher than that of the control. Bacterial community analysis indicated that Acidobacteria ($26.3{\pm}0.9%$), Proteobacteria ($24.2{\pm}0.5%$), Chloroflexi ($11.1{\pm}0.4%$), and Actinobacteria ($9.7{\pm}2.5%$) were abundant phyla in both treated and non-treated soils. In the treated soils, the relative abundance of Actinobacteria was lower, whereas those of Bacteroidetes and Firmicutes were higher compared to the control. Differences in total relative abundances of operational taxonomic units belonging to several genera were observed between the treated and non-treated soils, suggesting that inoculation of soil with the Bacillus strains influenced the relative abundances of certain groups of bacteria and, therefore, the dynamics of resident bacterial communities. These changes in resident soil bacterial communities in response to inoculation of soil with beneficial Bacillus spp. provide important information for the use of beneficial microorganisms in soil for sustainable agriculture.

• Journal of Life Science
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• v.20 no.9
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• pp.1402-1408
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• 2010

The effects of rice hull (RH) powder on the anticarcinogenic activity of submerged-liquid cultures of Agaricus blazei Murill (AB) were assessed for mouse ascites cancers induced by mouse Sarcoma S-180 (S-180) cancer cells. Optimal growth of AB mycelia in the basal liquid culture medium, containing soybean meal, was achieved by culturing at $25^{\circ}C$ for 5 days, when evaluated by $\beta$-glucan content, Brix, and mycelial weight, relative to other culture conditions. Hot-water extract (HWE) of the submergedliquid culture of AB mycelia grown at $25^{\circ}C$ for 5 days exhibited a stronger anticarcinogenic activity, relative to HWE from other culture conditions. No such effects were obtained from AB mycelial cultures by alternative temperature-controlling cultures. Both cytotoxicity for S-180 cells and anticarcinogenic potentials for mouse ascites cancer of the HWE from AB mycelia grown in the basal medium containing 1% RH powder for 5 days at $25^{\circ}C$ were significantly (p<0.05) enhanced, relative to HWE from the AB mycelia culture of the basal medium without RH powder. These results indicate that HWE of submerged-liquid culture of AB mycelia, incubated in media containing 1% RH powder at $25^{\circ}C$ for 5 days, enhanced anticarcinogenic activity against S-180 cell-induced mouse ascites cancer, and suggest that RH powder is an excellent ingredient for the improvement of the anticarcinogenic potentials of the submerged-liquid culture of mushroom mycelia.

• The Korean Journal of Pesticide Science
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• v.7 no.2
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• pp.139-148
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• 2003

The purpose of this study was to investigate damages of garlics occurred under cold storage and farmhouse storage condition, influence of cultural and environmental factors on storage spoilage of garlics, and to establish control strategies to reduce damages occurred under storage of garlics. Decays of garlics were highly related with cultural condition (paddy field or upland soil), ventilation, storage temperature and relative humidity, continuous cropping years, and harvesting stage. Early-harvested garlics were more decayed than late-harvested garlics. Garlics cultivated on paddy field were less decayed than ones cultivated on upland soil under farmhouse storage condition. The densities of Penicillium spp. and Fusarium spp. were higher on plot with long term continuous cropping cultivation history than on plot with short term continuous cropping cultivation history. However there is no relation between continuous cropping years and percent of decay of garlics. As a result of investigating influence of environmental factors on decay of garlics, P. hirsutum caused severe spoilage under high relative humidity condition, while F. oxysporum and Stemphyllium botryosum were not related with relative humidity. The three postharvest pathogens grew well above woe. In addition when P. hirsutum and S. botryosum were cultured for two months, they grew even at $-1^{\circ}C$. Except for environmental factors, wounds occurred through farming works. had an effect on storage spoilage of garlics. Garlics only hurt with a toothpick without inoculation of pathogens were decayed more severe than those inoculated with pathogens without wounds. Seven agro-chemicals showed highly suppressive effect were selected by measuring mycelial growth of three major pathogens of garlics on potato dextrose agar amended with 0.1% (v/v) of each fungicide. When they were foliar-sprayed on garlics 30 days before harvesting, it was confirmed that they suppressed storage spoilage of garlics. Also when garlics were sprayed with and drenched into the suspension of Benoram WP very after harvesting garlics, garlic damages by postharvest pathogens were reduced remarkably.

• Korean Journal of Poultry Science
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• v.48 no.1
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• pp.31-39
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• 2021

We aimed to investigate the age-dependent development of digestive organs, intestinal enzymes, and hepatic antioxidant defense system in White Leghorn chicks aged 0, 3, 7, 14, and 21 days. Body weight (BW) did not significantly change between days 0 and 7 but significantly increased (P<0.05) after day 7. The relative liver weight (g/100 g of BW) was significantly lower at day 0 than at the other ages but markedly increased at days 3 and 7 (P<0.05). The relative pancreatic weight changed similar to the change in liver weight, with the maximum development at 7 days (P<0.05). The relative intestinal and mucosal tissue weights increased rapidly after hatching (P<0.05), with the maximum growth at 7 days. Furthermore, maltase and sucrase activities were significantly higher at day 3 than at day 0 (P<0.05). Leucine aminopeptidase activity was high at day 0 and remained constant as age increased. Superoxide dismutase and glutathione S-transferase activities in the liver were the lowest at day 0 but significantly increased after 7 days (P<0.05). Glutathione peroxidase activity increased significantly after day 14 compared with that at days 0 and 7 (P<0.05). Lipid peroxidation was not affected by age. In conclusion, the digestive organ weights and hydrolase activity of chicks increased rapidly during the first 3 or 7 days post-hatching. Hepatic antioxidant enzyme activity increased simultaneously with the increase in digestive organ weights, after 7 days.

• Korean Journal of Ecology and Environment
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• v.55 no.3
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• pp.231-243
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• 2022

Anthropogenic disturbances on freshwater ecosystem are known to degrade biodiversity, especially on fish assemblage. In this study, we have conducted fish surveys to identify impact of a bridge construction on fish assemblages. A total of eight study sites were surveyed in the Danjang and the Dong Stream in southern part of South Korea from June to November in 2021. The fish samplings were carried out five times, using cast-nets(10×10 mm mesh size), scoop-nets(4×4 mm, 5×5 mm mesh size), set-nets (10×10 mm mesh size), and fish traps (3×3 mm mesh size), along with the Stream/River Ecosystem Survey and Health Assessment by the Ministry of Environment of Korea and basic water quality measurement. Also, we applied the species diversity index and length-weight relationship regressions on certain species to identify interspecific growth rate differences in accordance with study sites. As a result, a total of 782 individuals, 23 species and 10 families were collected. The dominant species was Zacco Koreanus and relative abundance was 50.89%. When applying the length-weight relationship regressions on certain species, the 'b' value for Z. Koreanus was lower at the downstream points than at the upstream points of the construction site. In addition, when comparing to the results of the past survey, relative density of demersal fish at the upstream and downstream points decreased from 26% to 1.4%, and from 18% to 6.3%, respectively. In conclusion, it is considered that bridge construction negatively affects the habitat of fishes, especially on demersal fishes. Therefore, appropriate conservation efforts such as installation of silt protector and sand sedimentation pond are needed to alleviate the disturbance in habitat such as occurrence of turbidity and destruction of micro-habitats.

• Korean Journal of Poultry Science
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• v.51 no.2
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• pp.57-63
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• 2024

As global warming worsens, it is feared that higher ambient temperatures and relative humidity might result in a more intense heat stress for livestock animals, especially broilers, which lack sweat glands for thermoregulation and have been selectively bred for rapid growth. Therefore, strategic livestock management is needed to mitigate the adverse effects of heat stress on broilers. In Korea's poultry farming systems, tunnel-ventilated broiler houses and pad cooling systems are commonly installed to lower indoor temperatures during the summer. However, caution is advised with pad cooling systems as they can increase the humidity inside the houses, potentially causing further harm. This study aimed to evaluate the effectiveness of pad cooling systems in tunnel-ventilated broiler house by assessing the reduction in indoor temperature using the Temperature-Humidity Index (THI), which accounts for the impact of relative humidity. Temperature and humidity data were collected during the summer (Jun to Sep) from eight farms with tunnel-ventilated broiler house located in different regions of Korea. The farms were divided into two groups based on the use of pad cooling systems is used, and temperature and humidity data, along with THI values, were analyzed two weeks before the birds were marketed. Meta-analysis results showed that at the hottest time of the day, 14:00, farms with pad cooling systems had significantly lower indoor temperatures compared to the control group, but observed an increase in indoor temperatures by 16:00 (p<0.05). There is no significant difference in relative humidity (p>0.05). The THI values decreased in the treatment group with cooling pads compared to the control group starting from 15:00, suggesting a diminished effect (p<0.05). This study indicates the potential for developing optimal operational guidelines for cooling pads to reduce heat stress in broilers during the summer season.

• Journal of Korean Society of Forest Science
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• v.75 no.1
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• pp.1-18
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• 1986

This study was initiated to estimate productivity of Quercus variabilis stand. However the practical objective of this study was to provide some information to establish the basis of selecting the suitable site for Quercus variabilis. The productivity measured in terms of DBH, height, basal area and stem volume was hypothesized, respectively, to be a function of a group of factors. This study considered 32 factors, 20 of which were related to the forest environmental factors such as tree age, latitude, percent slope, etc. and the rest of which were related to soil factors such as soil moisture, total nitrogen, available $P_2O_5$, etc. The data on 4 productivity measurements of Quercus variabilis growth and related factors cited were collected from 99 sample plots in Kyeongbook and chungbook provinces. Some factors considered were, in nature, discrete variables and the others continuous variables. Each kind of factor was classified into 3 or 4 categories and total numbers of such categories were eventually amounted to 110. Then each category was treated as an independent variable. This is amounted to saying that individual variable was treated a dummy variable and assigned a value 1 or 0. However the first category of each factor was deleted from the normal equation for statistical consideration. First of all, each of 4 productivity measurements of Quercus variabilis growth was regressed and, at the same time, those 110 categories. Secondly, the partial correlation coefficients were measured between each pair of 4 productivity measurements and 32 individual foctors. Finally, the relative scores were estimated in order to derive the category ranges. The result of these statistical analyses could be summarized as follows: 1) Growth measurement in terms of height seems to be a more significant criterion for estimation of productivity of Quercus variabilis. 2) Productivity of forest on stocked land may better be estimated in terms of forest environmental factors, on the other hand, that of unstocked land may be estimated in terms of physio-chemical factors of soil. 3) The factors that a strongly positive relation to all growth factors of tree are age group, effective soil, soil moisture, etc. This implies that these factors might effectively be used for criteria for selecting the suitable site for Quercus variabilis. 4) Parent rock, latitude, total nitrogen, age group, effective soil depth, soil moisture, organic matter, etc., had more significant category range for tree growth. Therefore, the suitable site for Quercus variabilis may be selected, based on this information. In conclusion, the above results obtained by the multivariable analysis can be not only the important criteria for estimating the growth of Quercus variabilis but also the useful guidance for selecting the suitable sites and performing the rational of Quercus variabilis forest.