• Korean Journal of Environmental Agriculture
• /
• v.42 no.2
• /
• pp.152-158
• /
• 2023

This study was conducted to evaluate the effects on soil chemical properties and plant growth after applying soldier fly compost (SFC). Treatments were as follows. No fertilizer (NF), control, SFC1 (SFC 250 kg/10a), SFC2 (SFC 500 kg/10a) and SFC3 (SFC 1,000 kg/10a). As compared to control in the pot test, organic matter (OM) and exchangeable sodium (Ex-Na) of SFC3 treatment were increased, and growth and nutrient uptake of young radish were not significantly different. Correlation coefficient between soil chemical factors like total nitrogen (T-N), OM, and CEC and uptake of nitrogen (N) and phosphorus (P) was significantly positive (p≤0.05). Compared to control in the field test, electrical conductivity, T-N, OM, Av.-P₂O₅, and CEC was increased, and lettuce growth was not significantly different. Correlation coefficient between application amount of SFC and T-N, OM, and Av.-P₂O₅ was significant positively (p≤0.05). These results indicated that the application of SFC improved nutrient availability of soil by increasing OM and CEC.

• Research in Plant Disease
• /
• v.10 no.2
• /
• pp.154-158
• /
• 2004

To analyze the relationship between CGMMV occurrence and seed contamination by cucumber cultivars, cucumber cultivars of CGMMV infected field and diseased degree were investigated in cucumber main cultivation regions of Jeonnam province from 1999 to 2002. While the diseased degree was different by years and cultivars, CGMMV occurred for 4 years in 'Janghyeongnakhap', for 3 years in 'Jangjukcheongjang', and for 2 years in 'Gyeoulsali' and 'Gyeoulnagi'. CGMMV was detected in seeds of 'Janghyeongnakhap' and 'Jangjukcheongjang' by ELISA test, and seed of 'Jangjukcheongjang' showed positive reaction in bioassay. As a result of resistant test of 34 cultivars to CGMMV, all cultivars showed mosaic symptoms in pot test but only 'Hanboksamcheok' showed mild mosaic symptom in field test.

• Korean Journal of Environmental Agriculture
• /
• v.32 no.4
• /
• pp.252-259
• /
• 2013

BACKGROUND: Salt accumulation in coastal reclaimed soil can decrease plant growth and productivity, which could lead to considerable variation of methane($CH_4$) emission in a rice paddy. The objective of this study was to evaluate the effect of salt concentration on $CH_4$ emission in a coastal reclaimed soil. METHODS AND RESULTS: The effect of salt concentration on $CH_4$ emission and rice growth characteristics was studied by pot test, which packed by reclaimed paddy soils collected from Galsa, Hadong, Gyeongnam province. Electrical conductivity(EC) of each treatment was controlled by 0.98, 2.25, 5.05 and 9.48 dS/m and $CH_4$ emission was characterized a week interval by closed chamber method during rice cultivation. The $CH_4$ emission rate was significantly decreased with increase of salt accumulation, but total $CH_4$ flux in EC 5.50 dS/m treatment was lower than those of EC 9.48 dS/m treatment. It seems because of higher content of water soluble $SO{_4}^{2-}$ in EC 5.50 dS/m treatment than those of EC 9.48 dS/m treatment. Rice growth and grain yield were significantly decreased with increase of salt accumulation. Soil properties, especially EC and pH were negatively correlated with $CH_4$ flux, while rice growth characteristics like plant height and tiller number show significantly positive correlation with $CH_4$ flux. CONCLUSION(S): Conclusively, salt accumulation significantly decreased $CH_4$ flux in a rice paddy, which could be useful information for evaluating $CH_4$ flux in reclaimed area in Korea.

• Microbiology and Biotechnology Letters
• /
• v.31 no.3
• /
• pp.235-241
• /
• 2003

For the biological control of Phytophthora blight of red-pepper caused by Phytophthora capsici, an antibiotic-producing plant growth promoting rhizobacteria (PGPR) Bacillus sp. KL 39 was selected from a local soil of Kyongbuk, Korea. The strain KL 39 was identified as Bacillus megaterium by various cultural, biochemical test and API and Microlog system. B. megaterium KL 39 could produce the highest antifungal antibiotic after 40 h of incubation under the optimal medium which was 0.4% fructose, 0.3% yeast extract, and 5 mM KCl at 30 C with initial pH 8.0. The antifungal antibiotic KL 39 was purified by Diaion HP-20 column, silica gel column, Sephadex LH-20 column, and HPLC. Its RF value was confirmed 0.32 by thin-layer chromatography with Ethanol:Ammonia:Water = 8:1:1. The crude antibiotic KL39 was active against a broad range of plant pathogenic fungi, Rhizoctonia solani, Pyricularia oryzae, Monilinia fructicola, Botrytis cinenea, Alteranria kikuchiana, Fusarium oxysporum and Fusarium solani. The purified antifungal antibiotic KL39 had a powerful biocontrol activity against red-pepper phytophthora blight disease with in vivo pot test as well as the strain B. megaterium KL 39.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.38 no.3
• /
• pp.202-208
• /
• 2002

Test fishing was carried out utilizing a coastal pot-fishing boat from IS March to 7 April 2002 and the results obtained are summarized as follows ; 1. Mean catches(Number of sea eels) according to the soak time of 3 hours, 6 hours and 12 hours were 44.6, 60.0 and 83.3, and CPUE(Number of catch / 10pots·hour) were 2.5, 1.7 and 1.1 respectively 2. Catch difference between over 24 hours and 48 hours was 11.3% and 3.3% between over 48 hours and 72 hours. 3. In the test fishing, by-catches were so low(1.5∼3%) until 12 hours of soaking time passed By-catches were increased according to the soaking time addition on the over 24 hours of soaking time. The bait effect for sea-eel seems to be diminished as soon as the casting started and there was big difference in proportion to bait size and freshness.

• Journal of Adhesion and Interface
• /
• v.21 no.2
• /
• pp.65-70
• /
• 2020

Epoxy adhesive was mainly used to combine different composite materials. Epoxy adhesive was a typical thermosetting resin that can be bonded by changing from a linear structure to a three-dimensional network structure by curing reaction of epoxy and hardener. The curing conditions of epoxy adhesive were different with different types of hardener such as mixing ratio, curing time, and temperature. These curing conditions affected to the adhesive property of epoxy adhesive. In industry, it was difficult to proceed the applying epoxy adhesive and combining two parts immediately. The adhesive property decreased by humidity and pre-curing of epoxy adhesive in waiting time between two processes. In this paper, the glass fiber reinforced composite (GFRC) was combined with epoxy adhesive and adhesion property between epoxy adhesive and GFRCs was evaluated using single lap shear test. The different waiting times and humidity conditions were applied to epoxy adhesive in room temperature and adhesive property decreased as the waiting time increased. In small amount of humidity, the adhesive property increased because a small amount of moisture in the surroundings accelerated the curing reaction. In certain amount of humidity, however, the adhesion property decreased.

• Korean journal of applied entomology
• /
• v.10 no.1
• /
• pp.31-38
• /
• 1971

Tolerance test in plastic vat, pot and fold tests were carried out to investigate the selective herbicides for soybean culture in sandy loam. The soybean plants showed great tolerance against herbicides such as Tri-allate (Avadex-BW), Alachlor (Lasso), Butachlor (Machete), Propachlor (Ramrod), Nitrofen (TOK), MO, HE-314, Nitrofen/Dinoseb(TOK/DNBP), and Chlo.oxu.on (Tenoran), and the growth was normal even when each was treated with the herbicides up to 2ft3 times of the recommended concentrations. Soybean plants showed a slight tolerance against Prometryne (Gesagard), Propazine (Gegamil), Diuron (Karmex), Metabromuron (Patoran), Linuron (Lorox) and Swep when each was treated with herbicides up to 1-2 times of the recommended concentrations. Great injury or withering was noticed due to the high sensitivity of soybean to Simazine (CAT) and to Floumetron (Cotoran). In pot and field experiments with herbicides such as Butachlor (Machete), Alachlor (Lasso), Nitrofen (TOK), Kerb, Nitrofen/Dinoseb (TOK/DNBP), Swep, Linuron (Lorox), Simazine (CAT) and PCP, the following results were obtained: Great injuries were noticed with Simazine (CAT). Also, Linuron (Lorox) and Kerb showed a slight injury at early growth stage of soybean, Nitrofen (TOK) , Nitrofen/Dinoseb (TOK/DNEP), Alachlo. (Lasso), Butachlo. (Machete) and Swep had high selectivities for soybean and no injury was noticed. With respect to herbicidal effects there was a greatly significant difference between treated plots and non-treated plots with the exception of Simaaine (CAT) plot in field test. E. crusgalli and C. sanguinalis were tolerant against Simazine(CAT) and Linuron(Lorox). Cyperus and E. annuus were tolerant against Kerb. Great herbicidal effects on grasses were observed in Alachlor (Lasso) and Butachlor (Machete) plots. Among broad-leaf weeds, P. hydropiper and C. album were tolerant against Butachlor (Machete) and Alachlor (Lasso). When soybean was treated with the herbicides such as Alachlor (Lasso) (ai. 150g/10a), Butachlor (Machete) (ai. 300g/10a), Nitrofen (TOK) (ai. 250g/10a), Linuron (Lorox) (ai. 75g/10a) once after seeding, no additional wording was required till harvest.

• Research in Plant Disease
• /
• v.19 no.1
• /
• pp.12-20
• /
• 2013

To isolate antagonistic bacteria against sclerotinia rot of lettuce, caused by Sclerotinia sclerotiorum, soil samples were collected from the diseased greenhouse field in Namyangju city, Gyeong-gi province from 2007 to 2008. A total of 196 bacterial isolates were isolated using serial dilution method. In dual culture assay in vitro, 26 isolates showed more than 80% of inhibition rates of mycelial growth of S. sclerotiorum. Based on 16S rDNA sequence analysis, the 26 isolates were identified as Bacillus megaterium, B. cereus, B. subtilis, Arthrobacter nicotianae, A. ramosus, Pseudomonas filiscindens, Stenotrophomonas maltophilia, Brevibacterium frigoritolerans and Sphingobacterium faecium. The 26 isolates inhibited the mycelial growth of S. sclerotiorum up to 80% and the sclerotial germination 0-100%. In the greenhouse pot test of ten isolates conducted in summer, 2 isolates B. megaterium (DK6) and B. cereus (C210) showed control efficacy on sclerotia viability of S. sclerotiorum, 20% and 35%, respectively. In the greenhouse pot test in winter, the disease incidence of the control group was 80%, whereas those of 9 isolates among 26 were approximately 20%. From the result, the 9 isolates are expected as potentially antagonistic bacteria for biological control of sclerotinia rot of lettuce caused by S. sclerotiorum.

• Korean Journal of Soil Science and Fertilizer
• /
• v.34 no.5
• /
• pp.311-315
• /
• 2001

In order to improve a soil test-based fertilization model for nitrogen, the Mitscherlich-Baule-Spillman equation modified by Bray and his coworkers was introduced and tested for its possibility of application. The coefficients $C_1$ and $C_2$ in the equation A were calculated by applying 10 pot experimental results done by the National Institute of Agricultural Sciences and Technology. Then, a regression(B) between C_1 and x, the fertilizer level was estimated. log(Ymax-Y) = logYmax-$C_1x-C_2b$ (A) where Ymax : maximum yield. Y : yield without or with a limited amount of fertilizer applied, x : application level of fertilizer, b : content of a nutrient in soil, $C_1$ and $C_2$ : coefficients of x and b, respectively. log(0.05)=$-C_1x-C_2b$ (B) Fertilizer requirement calculated by the equation B was significantly correlated with the real level of fertilizer applied for 95 percentage of the maximum yield. A more extensive and precise study on $C_1$ and $C_2$ in the equation A in expected to improve significantly the fitness of soil analysis to the fertilizer recommendation.

• The Plant Pathology Journal
• /
• v.18 no.1
• /
• pp.36-42
• /
• 2002

Resistance of perilla varieties to Botrytis cinerea LVF12 was evaluated, while antagonistic bacteria were selected and tested for their efficacy towards biological control of gray mold rot caused by B. cinerea. Among 11 perilla varieties tested for disease resistance, Milyang variety showed some degree of resistance, while the rest of varieties showed no resistance. Among 250 bacterial isolates collected from perilla loaves and rhizosphere of perilla plants, six isolates showed high levels of inhibitory effect on mycelial growth and conidial germination of B. cinerea in in vitro test. Using the pot test in growth chambers these isolates showed high levels of disease suppression, with Nl isolate showing 95.3% of control value and N4 isolate showing 90.8% of control value. Further test was performed to evaluate the two isolates ability for disease prevention and/or disease therapy, and results showed almost 100% of control vague. Isolates Nl and N4 were identified as Bacillus licheniformis and 5. megatepium, respectively, according to Bergey's manual, API 20E and 50CHB test kit, and Transmission electron microscope.