• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.583-593
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• 2015

This study was conducted to investigate the effects of mixed-sowing of legume forage and applying of cattle manure on the productivity of organic rye to provide dairy farmers with safe organic feeds. Also the present study aimed to evaluate optimal applying level of cattle manure and carrying capacity of Korean native cattle (Hanwoo) per unit area. The amount of crude protein was significantly higher in the mixed-sowing of legume forage (average 760~786 kg/ha) than in the single-sowing of rye (average 353 kg/ha) (p<0.05). The mixed-sowing of forage peas and the single-sowing of rye tended to improve by increasing the level of nitrous fertilization rather than the fertilization treatment. The amount of crude protein on the rye according to the mixed-sowing of legume was significantly higher in the mixture (average 8.29~9.90%) than in the single (average 4.93%) (p<0.05). The comparison by the level of nitrogen fertilization indicated significantly high for the rye in 50 kg N/ha than in fertilization treatments (p<0.05). Total digestible nutrients (TDN) amount in the single-sowing of rye was average 46.86% and has lower than average 49.96~50.12% of the mixed-sowing of legume, and especially the mixed-sowing of forage pea was the highest with 54.55% in 150 kg N/ha for the level of nitrogen fertilization (p<0.05). The breeding ability of annual organic livestocks per unit area according to the feed value of rye presented significantly higher ability in the mixed-sowing of legume (3.72~4.12 heads) than the single-sowing of rye (average 2.26 heads) (p<0.05). By summarizing above results, the mixed-sowing of legume is required to improve the productivity and the feed value of rye for increasing organic livestock breeding ability in southern area of Gyeongbuk regions, and the study for identifying the appropriate fertilization level using livestock excretions is further necessary.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.557-565
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• 2017

For our survey of insecticidal resistance of Palm thrips (Thrips palmi Karny), we established the discriminating time (DT) and concentration (DC) of nine insecticides, and we conducted a bioassay about seven local populations via leaf-dipping methods. The discriminating times of the recommended concentration (RC) were 24 h at emamectin benzoate EC and spinetoram SC, 48 h at chlorfenapyr EC, 72 h at spinosad SC, cyantraniliprole EC, acetamiprid WP, dinotefuran WG, imidacloprid WP and thiacloprid SC after treatment. The DC estimated the concentration which showed the difference within the mortalities of these local populations. The DCs were emamectin benzoate EC $0.013mg\;L^{-1}$ (RC, $10.8mg\;L^{-1}$), spinetoram SC $0.125mg\;L^{-1}$ (RC, $25.0mg\;L^{-1}$), chlorfenapyr EC $0.25mg\;L^{-1}$ (RC, $50.0mg\;L^{-1}$), spinosad SC $0.083mg\;L^{-1}$ (RC, $50.0mg\;L^{-1}$) and cyantraniliprole EC $5.0mg\;L^{-1}$ (RC, $50.0mg\;L^{-1}$), and DCs of neonicotinoids were their RCs, that is, acetamiprid WP (RC, $40.0mg\;L^{-1}$), dinotefuran WG (RC, $20.0mg\;L^{-1}$), imidacloprid WP(RC, $50.0mg\;L^{-1}$) and thiacloprid SC (RC, $50.0mg\;L^{-1}$). From our investigation into the resistance of the local populations with DT and DC application, the neonicotinoid insecticides have shown a high resistant level for all the local populations, and the other insecticides have demonstrated low or non-resistance. In the use of neonicotinoid insecticides to control Palm thrips, one must take caution. As a result, the establishment of DT and DC in the single dose bioassay method was helpful for surveying the insecticide response dynamics and the development of an insecticide resistance management strategy.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.796-801
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• 2001

A total of 277 mineral spring water samples in Kangwon province from 1999 to 2000 were analyzed for the presence of Yersinia spp. by the conventional Food and Drug Administration protocol, and presumptive strains were identified by morphological, cultural and biochemical tests according to Bergey’s manual. Also, the biotypes, serotypes, and susceptibility to 12 antibiotics were tested. Among the total 277 mineral spring water samples, 40 samples (14.4%) were found to be contaminated with Yersinia species. Among the 40 strains of Yersinia spp. isolates, 33 strains (82.5%) for Yersinia enterocolitica, 4 strains (10%) for Yersinia frederiksenii, 2 strains (5%) for Yersinia intermedia, and 1 strain (2.5%) for Yersinia sakazaki were identified, respectively. Of 40 Yersinia spp. isolates, Yersinia enterocolitica (82.5%) was the most predominant species in the mineral spring water samples compared to other Yersinia species. Compared to direct culture method after KOH treatment and KOH treatment method after cold enrichment for better isolation ratio of according to comparision of Yersinia species, the detection ration (18.5%) of KOH treatment method after cold enrichment was about 3 times better than that (6.1%) of direct culture method after KOH treatment. According to serotypes of Y. enterocolitica isolates, O : 5 (12.9%) was the most predominant and followed by O : 3 (9.7%), O : 8 (6.5%), and O : 9 (3.2%), and others. For biotypes of Y. enterocolitica isolates, 1A (71.0%) was the most predominantly abundant and followed by 3A (12.9%), 3B (9.7%), 1B (3.2%) and 5 (3.2%). Also, an antibiotic susceptibility test showed that Yersinia spp. isolates were very susceptible to the antibiotics tested, but they were very strongly resistant to ampicillin, cephalothin and carbenicillin.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.954-961
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• 2010

Ground-based remote sensing can be used as one of the non-destructive, fast, and real-time diagnostic tools for quantifying yield, biomass, and nitrogen (N) stress during growing season. This study was conducted to assess biomass and nitrogen (N) status of paddy rice (Oryza sativa L.) plants under N stress using passive and active ground-based remote sensors. Nitrogen application rates were 0, 70, 100, and 130 kg N $ha^{-1}$. At each growth stage, reflectance indices measured with active sensor showed higher correlation with DW, N uptake and N concentration than those with the passive sensor. NIR/Red and NIR/Amber indices measured with Crop Circle active sensors generally had a better correlation with dry weight (DW), N uptake and N content than vegetation indices from Crop Circle passive sensor and NDVIs from active sensors. Especially NIR/Red and NIR/amber ratios at the panicle initiation stage were most closely correlated with DW, N content, and N uptake. Rice grain yield, DW, N content and N uptake at harvest were highly positively correlated with canopy reflectance indices measured with active sensors at all sampling dates. N application rate explains about 91~92% of the variability in the SI calculated from NIR/Red or NIR/Amber indices measured with Crop Circle active sensors on 12 July. Therefore, the in-season sufficiency index (SI) by NIR/Red or NIR/Amber index from Crop Circle active sensors can be used for determination of N application rate.

• Journal of Sericultural and Entomological Science
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• v.53 no.2
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• pp.135-142
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• 2015

The American cockroaches, Periplaneta americana L. was the most important worldwide pest species. It has been an public health problems. We were determinated life cycle and extraction of crude extracts by chemical reagents from cockraches (P. americana L.). The extracted crude solution has been antibacterial activity to gram negative bacteria (Pseudomonas aeruginosa, $6.44{\pm}1.03mm$), gram positive bacteria (Bacillus subtilis, $1.88{\pm}0.40mm$), and fungus (Candida albicans, $5.61{\pm}0.57mm$) using radial diffusion assay. We were analysed of up-regulation of Glutathione-S-transferases (GSTs) stimulation, indicating that antioxidantial protein from various classes are simultaneously expressed in a single insect upon infection or injury. The gene from Periplaneta americana L. were cloned, analysed sequence, and measured protein expression by Real Time PCR (Polymerase Chain Reaction).

• Korean Journal of Poultry Science
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• v.48 no.3
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• pp.101-110
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• 2021

In this study, we performed a cross-combination test using offspring from two paternal and five maternal parent stock lines to produce a new synthetic breed of Korean native commercial chickens. The survival rate, body weight, feed intake, and feed efficiency were measured for 10 crosses, with 837 Hanhyup-3 chickens used as a control. Most chickens had brown-based feathers, and there was little difference in color phenotypes among combinations. The average survival rate of the combinations was 94.9%, which was significantly different from that of Hanhyup-3 at 75.3% (P<0.01). There was significant differences in body weight among the combinations at all weeks of age (P<0.01). At 10 weeks of age, the FHHY combination was the heaviest with 2,300 g, while the weight of Hanhyup-3 was 1,922 g. In addition, the weight difference between the male and female chickens was 458 g. As a result of regression analysis, the duration needed to reach 1.9 kg was about 61 days for the FHFY, FHHY, and HFFY combinations, and 70 days for Hanhyup-3, exhibiting a 9-day difference. The average feed conversion ratio of the combinations until 10 weeks was 2.42, which was significantly different from that of Hanhyup-3 at 2.97 (P<0.01). In conclusion, FHHY, FHFY, and HFFY were determined to be the best new breed combinations based on production capacity. When these combinations are used as new commercial breeds, they are expected to increase the average weight by 18% and improve feed efficiency by 19%, as compared to the existing Hanhyup-3 breed.

• Korean Journal of Environmental Agriculture
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• v.37 no.4
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• pp.235-242
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• 2018

BACKGROUND: About 81% of nitrous oxide ($N_2O$) emissions from agricultural land to the atmosphere is due to nitrogen (N) fertilizer application. Mitigation of $N_2O$ emissions can be more effective in controlling biochemical processes such as nitrification and denitrification in the soil rather than decreasing fertilizer application. The use of urease inhibitors is an effective way to improve N fertilizer efficiency and reduce $N_2O$ emissions. Several compounds act as urease inhibitors, but N-(n-butyl) thiophosphoric triamide (NBPT) has been used worldwide. METHODS AND RESULTS: Hot pepper and chinese cabbage were cultivated in five treatments: standard fertilizer of nitrogen-phosphorus-potassium(N-P-K, $N-P_2O_5-K_2O$: 22.5-11.2-14.9 kg/ha for hot pepper and $N-P_2O_5-K_2O$: 32.0-7.8-19.8 kg/ha for chinese cabbage), no fertilizer, and NBPT-treated fertilizer of 0.5, 1.0, and 2.0 times of nitrogen basal application rate of the standard fertilizer, respectively in Gyeonggi-do Hwaseong-si for 2 years(2015-2016). According to application of NBPT-treated fertilizer in hot pepper and chinese cabbage, $N_2O$ emission decreased by 19-20% compared to that of the standard fertilizer plot. CONCLUSION: NBPT-treated fertilizer proved that $N_2O$ emissions decreased statistically significant in the same growth conditions as the standard fertilization in the hot pepper and chinese cabbage cultivated fields. It means that NBPT-treated fertilizer can be applied for N fertilizer efficiency and $N_2O$ emissions reduction.

• Korean Journal of Environmental Agriculture
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• v.38 no.3
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• pp.166-172
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• 2019

BACKGROUND: Increase in the ratio of small berries in blueberry production decreases the farmers' profits due to weakening market competitiveness and lowering harvest efficiency. One of the reasons for increased small berries is over fruit-load. For improving productivity and competitiveness of blueberry in Korea, hand-thinning can be applied to increase fruit quality before the developing adequate chemical thinning methods. This study was conducted to investigate the proper timing and methods for floral buds thinning in rabbiteye blueberry. METHODS AND RESULTS: Eight years old bushes of rabbiteye bluberries 'Brightwell' as a primary cultivar and 'Powderblue' as a pollinizer were used for this study. Fruit size distribution by leaf-to-fruit ratio was investigated by counting the number of leaves and fruits in canes of 127 'Brightwell' plants whose fruit set varied. Fifty percent of flowers/floral buds were removed in four different floral buds stages such as bud swell, late pink bud, full bloom, and petal fall, and the consumed time for thinning and fruit characteristics were recorded to investigate the effect and proper timing of floral buds thinning. Fruit weight and soluble solids content tended to increase in proportion to leaf-to-fruit ratio and the production of the number of fruits less than 13 mm in diameter decreased when leaf-to-fruit ratio was more than 2.5. Manual floral buds thinning by hands was fastest in full bloom stage and slowest in bud swelling stage. In all cultivars, fruit size was significantly smaller in non-thinning treatment than thinning, and there was, however, no significant difference in total fruit yield. The number of fruits less than 13 mm in diameter increased in both cultivars as floral buds thinning was delayed. Consumed time for picking 90% berries out of total berries per bush was shortest in full bloom stage thinning in 'Brightwell' and bud swelling, full bloom thinning in 'Powderblue'. These were 25 and 20 days faster than no thinning, respectively. CONCLUSION: Although the effect of floral buds thinning varied depending on the cultivars, our results confirmed that floral buds thinning was effective for the early intensive harvesting and the increase of the large fruit ratio and the harvesting productivity. Also, in order to increase thinning efficiency, it is recommended to remove the flower buds before the full bloom stage.

• Journal of Korean Society of Forest Science
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• v.108 no.1
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• pp.29-39
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• 2019

The objective of this study was to suggest a suitable amount of fertilizer using the changes in growth performances and soil properties for improving survival and quality of Zelkova serrata trees in a harvested Pinus rigida plantation. One-year-old containerized seedlings of Z. serrata were planted with the density of 3000 seedlings $ha^{-1}$ in end of March 2011 at Gwangneung experimental forest, Pocheon. Solid compound fertilizer (N:P:K=3:4:1) were applied yearly in three amounts (control: no fertilization, F1: $180kg\;ha^{-1}$, and F2: $360kg\;ha^{-1}$) every May from 2011 to 2013. We analyzed soil properties before (2011) and after (2012 and 2017) fertilization. And we measured the root collar diameter and height of Z. serrata trees from 2011 to 2016, and then calculated H/D ratio and stem volume. Soil properties at Z. serrata plantation did not show difference according to fertilization level in every investigation year. As time passed after planting, however, concentrations of total nitrogen and available phosphorus were increased from decreased. The growth of root collar diameter, height and stem volume of Z. serrata trees at F2 plot were significantly higher those at the other plots after only 2 years of fertilization. Because Z. serrata tree demand to more nutrient during the early growing period. The survival rate of Z. serrata trees at control plot was significantly lower than that at the other plots. This might be due to Z. serrata trees at control plot had not the upper hand from competition with vegetation at the early in planting. However, the growth of height and stem volume of Z. serrata trees between F1 and F2 plots did not show difference over 6 years after planting. Consequently, we could suggest that Z. serrata trees need to F1 fertilization level for considering improving survival and quality of Z. serrata trees and economical efficiency of plantation managements after harvesting P. rigida plantation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.3
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• pp.204-212
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• 2019

The optimal application rate of a controlled release fertilizer (CRF) on the growth, yield, and seeding time of rice grown on seedling trays was investigated. The experimental field was located at $37^{\circ}22^{\prime}10^{{\prime}{\prime}}N$ latitude and $127^{\circ}03^{\prime}85^{{\prime}{\prime}}E$ longitude in Hwaseong, Gyeonggi-do, Republic of Korea. The soil in the paddy field was a clay loam. The CRF used in the experiment contained $300g\;kg^{-1}$ of nitrogen, $60g\;kg^{-1}$ of phosphate, and $60g\;kg^{-1}$ of potassium, respectively. The CRF was applied at the rate of 0, 200, 300, 400, 500, and 600 grams on rice seedling tray compared with the field application based on soil testing (control), respectively. The CRF can be applied as single application(which can replace basal fertilizer application and two top dressing application) directly to the seedling tray, and showed the minimum release at the seedling period. Considering the plant growth, nitrogen use efficency and yield of rice, the optimal application rate of developed CRF was 500 g per seedling tray and the yield of rice at this application rate was $4.92{\sim}5.04Mg\;ha^{-1}$. The regression formula between the rice yield and application rates of CRF was as follows ; "$Y=0.0002{\chi}^2+0.0963{\chi}+411.6$($R^2$ : 0.9922) in 2010 and $Y=8E-6{\chi}^2+0.2723{\chi}+344.04$($R^2$:0.9864) in 2011, Y : Rice yield ($Mg\;ha^{-1}$), ${\chi}$ : Application rate (grams) of controlled release fertilizer". The optimum application rates of CRF per rice seedling tray by regression formula was 498 grams in 2010 and 513 grams in 2011.