• Korean Journal of Organic Agriculture
• /
• v.27 no.4
• /
• pp.479-499
• /
• 2019

This study was conducted to investigate the responses of soil properties and microbial communities to different agricultural management and soil types, including organic management in Andisols (Org-A), organic management in Non-andisols (Org-NA), conventional management in Andisols (Con-A) and conventional management in Non-andisols (Con-NA) by using a pyrosequencing approach of 16S rRNA gene amplicon in Radish farms of volcanic ash soil in Jeju island. The results showed that agricultural management systems had a little influence on the soil chemical properties but had significant influence on microbial communities. In addition, soil types had significant influences on both the soil chemical properties and microbial communities. Organic farming increased the microbial density of bacteria and biomass C compared to conventional farming, regardless of soil types. Additionally, Org-NA had the highest dehydrogenase activity among treatments, whereas no difference was found between Org-A, Con-A and Con-NA and had the highest species richness (Chao 1) and diversity (Phyrogenetic diversity). Particularly, Chao 1 and Phyrogenetic diversity were increased in organic plots by 12% and 20%, compared with conventional plots, respectively. Also, regardless of agricultural management and soil types, Proteobacteria was the most abundant bacterial phylum, accounting for 21.9-25.9% of the bacterial 16S rRNAs. The relative abundance of putative copiotroph such as Firmicutes was highest in Org-NA plot by 21.0%, as follows Con-NA (13.1%), Con-A (6.7%) and Org-A (5.1%.), respectively and those of putative oligotrophs such as Acidobacteria and Planctomycetes were higher in Con-A than those in the other plots. Furthermore, LEfSe indicated that organic system enhanced the abundance of Fumicutes, while conventional system increased the abundance of Acidobacteria, especially in Non-andisols. Correlation analysis showed that total organic carbon (TOC) and nutrient levels (e.g. available P and exchangeable K) were significantly correlated to the structure of the microbial community and microbial activity. Overall, our results showed that the continuous organic farming systems without chemical materials, as well as the soil types made by long-term environmental factors might influence on soil properties and increase microbial abundances and diversity.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.19 no.1
• /
• pp.4279-4295
• /
• 1977

Two types of model were established in order to product the soil moisture content by which information on irrigation could be obtained. Model-I was to represent the soil moisture depletion and was established based on the concept of water balance in a given soil profile. Model-II was a mathematical model derived from the analysis of soil moisture variation curves which were drawn from the observed data. In establishing the Model-I, the method and procedure to estimate parameters for the determination of the variables such as evapotranspirations, effective rainfalls, and drainage amounts were discussed. Empirical equations representing soil moisture variation curves were derived from the observed data as the Model-II. The procedure for forecasting timing and amounts of irrigation under the given soil moisture content was discussed. The established models were checked by comparing the observed data with those predicted by the model. Obtained results are summarized as follows: 1. As a water balance model of a given soil profile, the soil moisture depletion D, could be represented as the equation(2). 2. Among the various empirical formulae for potential evapotranspiration (Etp), Penman's formula was best fit to the data observed with the evaporation pans and tanks in Suweon area. High degree of positive correlation between Penman's predicted data and observed data with a large evaporation pan was confirmed. and the regression enquation was Y=0.7436X+17.2918, where Y represents evaporation rate from large evaporation pan, in mm/10days, and X represents potential evapotranspiration rate estimated by use of Penman's formula. 3. Evapotranspiration, Et, could be estimated from the potential evapotranspiration, Etp, by introducing the consumptive use coefficient, Kc, which was repre sensed by the following relationship: Kc=Kco$.$Ka＋Ks‥‥‥(Eq. 6) where Kco : crop coefficient Ka : coefficient depending on the soil moisture content Ks : correction coefficient a. Crop coefficient. Kco. Crop coefficients of barley, bean, and wheat for each growth stage were found to be dependent on the crop. b. Coefficient depending on the soil moisture content, Ka. The values of Ka for clay loam, sandy loam, and loamy sand revealed a similar tendency to those of Pierce type. c. Correction coefficent, Ks. Following relationships were established to estimate Ks values: Ks=Kc-Kco$.$Ka, where Ks=0 if Kc,=Kco$.$K0$\geq$1.0, otherwise Ks=1-Kco$.$Ka 4. Effective rainfall, Re, was estimated by using following relationships : Re=D, if R-D$\geq$0, otherwise, Re=R 5. The difference between rainfall, R, and the soil moisture depletion D, was taken as drainage amount, Wd. {{{{D= SUM from { {i }=1} to n (Et-Re-I+Wd)}}}} if Wd=0, otherwise, {{{{D= SUM from { {i }=tf} to n (Et-Re-I+Wd)}}}} where tf=2∼3 days. 6. The curves and their corresponding empirical equations for the variation of soil moisture depending on the soil types, soil depths are shown on Fig. 8 (a,b.c,d). The general mathematical model on soil moisture variation depending on seasons, weather, and soil types were as follow: {{{{SMC= SUM ( { C}_{i }Exp( { - lambda }_{i } { t}_{i } )+ { Re}_{i } - { Excess}_{i } )}}}} where SMC : soil moisture content C : constant depending on an initial soil moisture content $\lambda$ : constant depending on season t : time Re : effective rainfall Excess : drainage and excess soil moisture other than drainage. The values of $\lambda$ are shown on Table 1. 7. The timing and amount of irrigation could be predicted by the equation (9-a) and (9-b,c), respectively. 8. Under the given conditions, the model for scheduling irrigation was completed. Fig. 9 show computer flow charts of the model. a. To estimate a potential evapotranspiration, Penman's equation was used if a complete observed meteorological data were available, and Jensen-Haise's equation was used if a forecasted meteorological data were available, However none of the observed or forecasted data were available, the equation (15) was used. b. As an input time data, a crop carlender was used, which was made based on the time when the growth stage of the crop shows it's maximum effective leaf coverage. 9. For the purpose of validation of the models, observed data of soil moiture content under various conditions from May, 1975 to July, 1975 were compared to the data predicted by Model-I and Model-II. Model-I shows the relative error of 4.6 to 14.3 percent which is an acceptable range of error in view of engineering purpose. Model-II shows 3 to 16.7 percent of relative error which is a little larger than the one from the Model-I. 10. Comparing two models, the followings are concluded: Model-I established on the theoretical background can predict with a satisfiable reliability far practical use provided that forecasted meteorological data are available. On the other hand, Model-II was superior to Model-I in it's simplicity, but it needs long period and wide scope of observed data to predict acceptable soil moisture content. Further studies are needed on the Model-II to make it acceptable in practical use.

• Journal of Animal Science and Technology
• /
• v.53 no.5
• /
• pp.397-408
• /
• 2011

The study was carried to identify the impact on nation-wide genetic evaluation and to obtain basic materials for the development of strategies in Swine Improvement Network Project (SINP). Data consisted of pedigree records of 235,511 and performance records of 70,747 for Duroc from 1987 to 2010 were collected by Korea Animal Improvement Association. Performance traits included three point back fat thickness (Shoulder, Belly, Waist), loin area, days to 90 kg and average daily gain. Exchange of genetic resources cross the breeding farms was not high, and furthermore the sizable farms which can accommodate genetic evaluation within the farm were scarce. Three data sets (individual farm evaluation: I, two sub-group evaluation: S, and whole eight farm evaluation: P) were used for genetic analysis. Genetic variances were larger in subordinate farms than in joiners farms for connectedness, and consequently the heritabilities were generally higher in subordinate farms than in joiner farms with I. The standard errors of heritability were small in the order of I, S and P. Estimated average inbreeding coefficients were 1.12%, 0.95% and 1.53% for joiner and subordinate group with S and population with P, respectively. The estimated correlations of breeding values with I and P were lowest. The correlations of breeding values with I and P for traits ranged 0.22 to 0.45 for moved parent animals and 0.24 to 0.72 for all animals. The results in the study suggest that nation-wide evaluation uses more pedigree information and improves accuracy. Furthermore SINP for connectedness could help to improve the accuracy of evaluation.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.60 no.4
• /
• pp.484-490
• /
• 2015

Thirty-eight Pea (Pisum sativum L.) genotypes were screened to identify varieties to be suitable for sprout. Based on seed yield and sprout qualities such as whole length and sprout yield, five genotypes (PI269803, PI343278, PI343283, PI343300 and PI 343307) were primarily selected as candidates for pea sprouts. In order to determine optimal cultivation condition for pea sprouting, growth characteristics were investigated according to the change of germination temperature and days for sprouting. Whole length and hypocotyl length were observed to increase as a time dependent manner at each tested temperature (20, 23, and $25^{\circ}C$). However, whole length, hypocotyl length, and sprout yield were highly increased at $23^{\circ}C$ compared to 20 and $25^{\circ}C$. Especially, PI269803 and PI343300 showed higher sprout yield than the others. In addition, the effect of the change of germination temperature on antioxidant properties was estimated by measuring total phenolic content (TPC) and free radical scavenging activity (DPPH and ABST activity). TPC and DPPH/ABST activities of PI269803 and PI343300 were higher at $23^{\circ}C$ than at 20 and $25^{\circ}C$, while antioxidant properties of PI343278 and PI343283 were decreased in a temperature-dependent manner. The results show a high degree of correlation between TPC and antioxidant activities and suggest that the temperature change for pea sprouting could be responsible for antioxidant properties. Taken together, these results provide optimal cultivation conditions for pea sprouting and suggest that PI269803 and PI343300 with high sprout yield and antioxidant properties could be used for pea sprouts.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.61 no.1
• /
• pp.17-24
• /
• 2016

Drought caused by global climate change is one of serious problems for rice cultivation. However, it was little reported the impact of drought on rice cultivation in Korea. In here, to assess impact of drought on rice varieties in Korean climate condition, growth characteristics and yield components of rice were compared on irrigated and partially irrigated rice paddy field. First, we have chosen 11 rice varieties including 'Saeilmi' and 'Shindongjin' which are widely cultivated in Korea. For partially irrigated rice paddy treatment, we have withheld irrigation from 25 days after transplanting and water supply was totally dependent on rainfall for rice cultivation. When we examined early plant height and tiller number of these varieties on partially irrigated rice paddy were reduced 1.6% to 18.4% and 10.4% to 33.1%, respectively, and these reduction rate were highly correlated with yield loss in our experimental conditions. Among rice yield components, panicle number was decreased 10.5% to 30.1% according to rice varieties and reduced panicle number was highly correlated with yield loss. Grain number per panicle, grain filling rate and 1,000 seeds weight did not have correlation with yield loss of rice varieties. These result means that growth stage, especially the tillering stage, is seriously affected by drought on rice cultivation in Korea. And we suggest that 'Saeilmi', 'Ilmi' and 'Ilpum' are good for rice cultivation on drought prone rice field in Korea.

• Korean Journal of Environmental Agriculture
• /
• v.36 no.2
• /
• pp.113-118
• /
• 2017

BACKGROUND: The carbon (C) isotope ratio (${\delta}^{13}C$) of dissolved organic C (DOC) is an indicator of water pollution source. In this study, the potential use of two pre-treatments for the ${\delta}^{13}C$ analysis, alkaline persulfate oxidation coupled with carbonate precipitation (precipitation) and freeze drying (drying), were compared to suggest a more feasible pre-treatment method. METHODS AND RESULTS: Two reference materials with different ${\delta}^{13}C$ values were used for the experiments; chemical grade glucose ($-12.0{\pm}0.02$‰) and pig manure compost extract ($-23.3{\pm}0.04$‰). In the precipitation method, the measured ${\delta}^{13}C$ values were consistently lower than the theoretically calculated values as dissolved $CO_2$ could not be removed due to the alkaline property of the reagents and the dissolution of air $CO_2$ into the alkaline solution. The drying method also resulted in more negative ${\delta}^{13}C$ than the calculated ${\delta}^{13}C$; however, the difference was systematic ($3.9{\pm}0.3$‰) and there was a strong correlation (${\delta}^{13}C_{calculated}=0.87{\times}{\delta}^{13}C_{measured}-0.624$, $r^2=0.98$) between the calculated and measured ${\delta}^{13}C$. Calibration of ${\delta}^{13}C$ using the relationship between the calculated and the measured ${\delta}^{13}C$ values produced reliable and accurate ${\delta}^{13}C$ values. CONCLUSION: Our results suggest that the drying method is more accurate pre-treatment method to minimize the influence of air $CO_2$ compared to the precipitation method for the determination of ${\delta}^{13}C$ of DOC.

• Journal of Food Hygiene and Safety
• /
• v.32 no.4
• /
• pp.298-305
• /
• 2017

Benzovindiflupyr is a new pyrazole carboxamide fungicide that inhibits succinate dehydrogenase of mitochondrial respiratory chain. This study was carried out to develop an analytical method for the determination of benzovindiflupyr residues in agricultural commodities using LC-MS/MS. The benzovindiflupyr residues in samples were extracted by using acetonitrile, partitioned with dichloromethane, and then purified with silica solid phase extraction (SPE) cartridge. Correlation coefficient ($r^2$) of benzovindiflupyr standard solution was 0.99 over the calibration ranges ($0.001{\sim}0.5{\mu}g/mL$). Recovery tests were conducted on 5 representative agricultural commodities (mandarin, green pepper, potato, soybean, and hulled rice) to validate the analytical method. The recoveries ranged from 79.3% to 110.0% and then relative standard deviation (RSD) was less than 9.1%. Also the limit of detection (LOD) and limit of quantification (LOQ) were 0.0005 and 0.005 mg/kg, respectively. The recoveries of interlaboratory validation ranged from 83.4% to 117.3% and the coefficient of variation (CV) was 9.0%. All results were followed with Codex guideline (CAC/GL 40) and Ministry of Food and Safety guideline (MFDS, 2016). The proposed new analytical method proved to be accurate, effective, and sensitive for benzovindiflupyr determination and would be used as an official analytical method.

• Horticultural Science & Technology
• /
• v.34 no.6
• /
• pp.871-877
• /
• 2016

Recycling nutrient solutions in closed hydroponic production systems is usually accompanied by an imbalance of nutrient solutions when concentration is controlled according to electrical conductivity (EC) levels. This study investigated whether it was possible to automatically control the concentrations of five essential elements nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) using only N, K and Ca ion sensors. N, P, K, Ca, and Mg uptake was measured in the nutrient solution, and relationships between absorbed ions were analyzed through twice-repeated experiments in lettuce. Results confirmed that the pattern of $PO_4$ ion uptake was similar that of N, and the pattern of Mg ion uptake was similar that of Ca. $PO_4$ ion uptake was most highly correlated with N, and Mg was most highly correlated with Ca. Regression coefficients of N and $PO_4$ were significantly different at 1.04 and 0.55, respectively, but were similar between Ca and Mg at 0.35 and 0.40, respectively. Additional experiments were conducted to measure nutrient uptake in pak choi and rose plants, both to confirm the results from the first experiment in lettuce, and to assess possible application to other crops. Coefficients of determination both for N and $PO_4$, and Ca and Mg were considerably high ($R^2=0.86$) in cultured pak choi, and similar results were observed in cultured rose ($R^2=0.87$ and 0.73, respectively). Regression coefficients for cultured pak choi were 0.56 and 0.24, respectively, and for rose were 0.51 and 0.16, respectively. Although the results obtained for N and $PO_4$ were not consistent between the lettuce experiments, N and $PO_4$ have similar regression coefficients for all crops. No common coefficient was found between Ca and Mg.

• Korean Journal of Food Science and Technology
• /
• v.42 no.1
• /
• pp.103-108
• /
• 2010

To obtain the best yield of the beneficial ingredients in green tea, such as catechins, green tea powder is most often prepared by ethyl alcohol extraction. However, the taste, cost and composition of ethyl alcohol extract is different from aqueous spray-dried green tea extract (aq-GTE). Specifically, aq-GTE has a better flavor, lower production costs and higher purity when compared to ethyl alcohol extract. In this study, we elucidated the effect of aq-GTE on diet-induced obesity in male C57BL/6J mice following dose-dependent oral administration of aq-GTE. After eight weeks, the body weight was reduced by 13-17% in mice fed 200 mg/kg bw aq-GTE ($12.468{\pm}0.45\;g$; p<0.05) and 20-25% in mice fed 400 mg/kg bw aq-GTE ($11.259{\pm}0.61\;g$; p<0.05) when compared with the high-fat diet (HFD) control group mice ($14.714{\pm}0.95\;g$; p<0.05). The correlation between epididymal fat accumulation and body weight also decreased by approximately 26.6% (p<0.05) in mice fed a HFD with aq-GTE 400 mg/kg bw. Finally, serum parameters such as the triglyceride, glucose and cholesterol levels in the HFD groups were reduced by the aq-GTE 400 mg/kg bw diet. Analysis on glutamic-pyruvic transaminase, blood urea nitrogen and development of hepatic steatosis revealed no histologic evidence of hepatotoxicity in HFD mice fed aq-GTE. Overall, our results imply that aq-GTE is able to regulate body weight and fat accumulation in mice.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.5
• /
• pp.2142-2147
• /
• 2012

This study is aimed at decreasing wrong diagnosis with corrected EF(Ejection Fraction) of 2D echo cardiography by analysing the physical time-resolution difference between Cine MRI and 2D echo cardiography and applying the corrected EF in 2D echocardiography. From February 2010 to December 2011, among the 110 patients who had undergone both 2D echo cardiography and cine MRI only 37 patient were selected suffering aortic valve regurgitation. ED, ES and SV were measured and EF was calculated in each system while normal ranges of Cine MRI and 2D echocardiography were compared to evauate misdiagnosis rate. The correlation of physical time resolution between 2D echocardiography and MRI was evaluated and the differences were corrected with linear regression coefficient which is derived from linear regression analysis. Blandt-Altman plot was used to evaluate the reliability of corrected 2D echo cardiography EF and compare the error among measured values. The values were compared with MRI normal range and misdiagnosis rate was measured again. As a result, misdiagnosis rates of physical time resolution were measured to be 32.4%(12people) before the correction of EF and 18.9%(7people) after the correction. Also, EF confirmed in Blandt-Altman plot were almost the same with MRI EF. In conclusion, when diagnosing aortic regurgitation disease, simply using 2D echocardiography can easily raise the misdiagnosis rates, therefore considering the MRI machine's physical merits, correcting the time resolution difference is important by calculating time resolution wrong diagnosis would decrease and it is considered to be useful in clinical circumstances.