• Korean Journal of Soil Science and Fertilizer
• /
• v.16 no.1
• /
• pp.42-49
• /
• 1983

In order to find out the possibility of predicting fertilizer K requirement from the K supplying capacity of soil, the relative K activity ratio, Kas/kai, the potential buffering capacity of $K^+$ ($PBC^k$ ; the liner regression coefficient) and its activity ratio ($AR^k_o$ ; $^{k+}$/${\sqrt{Ca^{+2}+Mg^{+2}}}$ in mol/l) at ${\delta}K$ = O, in the Q/I relationships of Beckett(1964), were determined for the soils before flooding and the samples taken at heading stage of transplanted rice in pot experiment. These parameters assumed as the K supplying capacity of soils were subjected for the investigation through correlation stady between themselves and other factors such as grain yield or the amounts of $K_2O$ uptake by rice plant at harvest. The results may be summarized as follows; 1. The potassium supplying power of the flooded soil was considered to be ruled by the amounts of exchangeable K before flooding, since there was little change in exchangeable K concentration from no-exchangeable K during the incubation periods of 67 days. 2. The $PBC^k$ values, in soils before flooding were 0.027, 0.014 and 0.009, where as the $AR^k_o{\times}10^{-3}$ values were 9.1, 7.6, and 15.4, respectively, in clay, loamy and sandy loam soils. 3. The $PBC^k$ values, determined in the soil samples taken at heading stage, varied little compared with the values of orignal soil, regardless of those different fertilizer treatments and textures, showing the possibility of using them as a factor for the improvement of soil to increase the efficiency of fertilizer K. 4. The significant yield responses to potassium fertilizer application were observed wherever the $AR^k_o$ values in soil at heading stage drop down to the original $AR^k_o$ values, regardless of any levels of fertilizer application. 5. The higher correlations between the gain yield or the amounts of $K_2O$ uptake and by the use of both soil factors of $PBC^k$ and $AR^k_o$ at heading stage were observed compared with the use of any single factor. 6. The Kas/Kai value in the soil, estimated prior to the experiment, had high possitive correlation with the $AR^k_o$ determined in the soil at heading stage and could be used as a soil factor for predicting potassium fertilizer requirement.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.4 no.4
• /
• pp.224-236
• /
• 2002

A long-term growth simulation was performed at 496 land units in the western coastal plains (WCP) of North Korea to test the potential adaptability of each land unit for growing South Korean rice cultivars. The land units for rice cultivation (CZU), each of them represented by a geographically referenced 5 by 5 km grid tell, were identified by analyzing satellite remote sensing data. Surfaces of monthly climatic normals for daily maximum and minimum temperature, precipitation number of rain days and solar radiation were generated at a 1 by 1 km interval by spatial statistical methods using observed data at 51 synoptic weather stations in North and South Korea during 1981-2000. Grid cells felling within a same CZU and, at the same time, corresponding to the satellite data- identified rice growing pixels were extracted and aggregated to make a spatially explicit climatic normals relevant to the rice growing area of the CZU. Daily weather dataset for 30 years was randomly generated from the monthly climatic normals of each CZU. Growth and development parameters of CERES-rice model suitable for 11 major South Korean cultivars were derived from long-term field observations. Eight treatments comprised of 2 transplanting dates $\times$ 2 cropping systems $\times$ 2 irrigation methods were assigned to each cultivar. Each treatment was simulated with the randomly generated 30 years' daily weather data (from planting to physiological maturity) for 496 land units in WCP to simulate the growth and yield responses to the interannual climate variation. The same model was run with the input data from the 3 major crop experiment stations in South Korea to obtain a 30 year normal performance of each cultivar, which was used as a "reference" for comparison. Results were analyzed with respect to spatial and temporal variation in yield and maturity, and used to evaluate the suitability of each land unit for growing a specific South Korean cultivar. The results may be utilized as decision aids for agrotechnology transfer to North Korea, for example, germplasm evaluation, resource allocation and crop calendar preparation.

• Journal of Korea Water Resources Association
• /
• v.49 no.3
• /
• pp.227-239
• /
• 2016

This study is to estimate Surface Energy Balance Algorithm for Land (SEBAL) daily spatial evapotranspiration (ET) comparing with eddy covariance flux tower ET in Seolmacheon mixed forest (SMK) and Cheongmicheon rice paddy (CFK). The SEBAL input data of Albedo, Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI) from Terra MODIS products and the meteorological data of wind speed, and solar radiation were prepared for 2 years (2012-2013). For the annual average flux tower ET of 302.8 mm in SMK and 482.0 mm in CFK, the SEBAL ETs were 183.3 mm and 371.5 mm respectively. The determination coefficients ($R^2$) of SEBAL ET versus flux tower ET for total periods were 0.54 in SMK and 0.79 in CFK respectively. The main reason of SEBAL ET underestimation for both sites was from the determination of hot pixel and cold pixel of the day and affected to the overestimation of sensible heat flux.

• The Korean Journal of Community Living Science
• /
• v.20 no.3
• /
• pp.423-435
• /
• 2009

Meal menus were developed and applied for rural elderly of Gangwon and Chungnam areas at agricultural off-season. Amounts of the major nutrients of carbohydrate, protein, lipid, and calorie considered in the menu based on the dietary reference intakes(DRI) of the elderly aged over 65 years were 97.5g, 22.5g, 13.3g, and 600kcal, respectively. In Chungnam, softness and overall acceptance of rice in menu 4, consisted of cereals and rice, kimchi stew with tuna, pan-fried bulgogi mushroom, seasoned dropwort carrot, kimchi, and banana, scored the highest values of 8.5 out of 9.0point hedonic scale (p<0.05). In Gangwon, soup and side dish of menu 3 (rice, frozen pollack pot stew, meatball fried in egg, seasoned sea lettuce, and banana) scored significantly the highest of all (p<0.05). Overall acceptance of all the menus were high over 7.8 without significance in Chungnam. Overall acceptance of the menu 3 scored significantly the highest with value of 8.5 and menu 4 (rice, spicy chicken soup, seasoned bean sprouts, broiled brown seaweed trunk, kimchi, tomato) had significantly the lowest value with value of 7.8 in Gangwon(p<0.05). The total leftover volume of menu 4 was significantly the highest with score of 56g and the menu 4 showed the highest unit cost of 2,900won in Chungnam. However, the total leftover volume of all menus did not show significance ranging from 9g to 19g in Gangwon.

• Korean Journal of Environmental Agriculture
• /
• v.4 no.1
• /
• pp.25-30
• /
• 1985

In order to characterize relationship between accumulation of cadmium, zinc and lead in soil and soil chemical properties and also to choose a suitable soil extractant for the prediction model of heavy metal content in brown rice, four extractants-0.1 M HCl, 0.1 M $HNO_3$, 0.1 M $NH_4-oxalate$ and 0.001 M 2Na-EDTA, were compared by analyzing 84 soil samples collected from paddy fields adjacent to five zinc-minig sites. Contents of Cd, and Pb in soil increased with Zn content and those of three elements were found to be much higher in surface soil ($0{\sim}15 cm$) than suvsqrface soil ($15{\sim}30 cm$). Contents of these elements in soil were positively correlated with soil pH, but its correlation between extractable heavy metal content and organic matter or CEC varied from region to region. These three elements were negatively correlated with Mg content of soils. The extractability of the metals was in the order 0.1 M $HCI{\geq}0.1 M$ $HNO_3>0.001 M$ 2Na-EDTA>0.1 M $NH_4-oxalate$.

• Korean Journal of Food Science and Technology
• /
• v.43 no.4
• /
• pp.453-457
• /
• 2011

The effect of the amount of water added during fermentation on the quality of takju (rice beer) was investigated. Takju was made by adding water 2-fold (A), 4-fold (B), 5-fold (C), and 6-fold (D), respectively, of the rice weight (w/w). Although the amount of takju increased in proportion to the amount of water added before fermentation, the amounts of B, C, and D were 1.17-1.19 times larger than the amount in A, and the total acidities of B, C, and D were 1.34, 1.40 and 1.46 times higher than those in A after adjusting alcohol content to 6%(v/v). Moreover, the sensory preferences for B, C, and D were higher overall than those for A, which was suggested to be due to the amount of sweet, sour, and bitter tastes as well as body in A. Different types of takju could be made by changing the amount of water added before fermentation.

• Korean journal of applied entomology
• /
• v.21 no.1 s.50
• /
• pp.38-48
• /
• 1982

This study was conducted to investigate the changes in moth occurrence of striped rice barer, Chilo suppressalis (Walker), in relation to climatic factors, rice varieties, and cultural practices. The light trap data from 41 forecasting stations for 14 years from 1966 to 1979 were analyzed by means of the changes in the time and amount of borer occurrence in connection with the introduction of new rice varieties, the accumulated effective day-degree and its variation for completing one generation, and the climatic factors affecting the moth occurrence. The total number of moths caught by light traps in both spring and summer generations were considerably decreased with the wide cultivation of new rice varieties. In fact, the spring moths were remarkably decreased since the new varieties were introduced in 1972. The occurrence ratio of summer moths against the preceeding spring moths was higher in the middle region and middle southern mountainous area than the other regions. Its high ratio of regions was annually expanded from the middle region to the southern region. The $50\%$ emergence dates of both generations were later in the southeastern region than in the middle region. The ecological characteristics were clearly shown between the northern and southern region of Chupungryeong in terms of the occurrence of summer moths, the ratio of occurrence of summer moths to the preceeding spring moths, and $50\%$ emergence dates of the summer moths during the years of $1977\~1979$. The ratio of the summer moth occurrence to the preceeding generation was negatively correlated with the average temperature in lune and July, respectively, and the average precipitation in late June. The ratio of spring moth occurrence over the preceeding generation was positively correlated with the average temperature in September, October, November, and March, respectively, whereas it was negatively correlated with the average precipitation in early September and March, and the average humidity in early May. The effective day-degree for one generation was in the range from 600 to 900 DD at upper threshold $30^{\circ}C$ and lower threshold $10^{\circ}C$.

• Journal of Life Science
• /
• v.17 no.4 s.84
• /
• pp.510-514
• /
• 2007

This study was carried on cool and RT(room temperature) storage of unhulled rice. In RT storage of an analysis of coefficient relation, high significant positive coefficients were observed in toyo index and breakdown, setback and protein content. high significant negative coefficients were showed setback and breakdown, breakdown and protein content. In cool storage of an analysis of coefficient relation, high significant positive coefficients were observed in toyo index and amylose content and gelatinization start temperature and protein content and high significant negative coefficients were showed toyo index and whiteness, toyo index and gelatinization start temperature, gelatinization start temperature and amylose content. In RT storage of a path coefficient analysis, a highest positive direct influence was observed in amylose content and a highest negative direct influence was protein content. Positive indirect influence was high revealed breakdown and protein content and negative indirect influence was gelatinization start temperature and Mg/K ratio. In cool storage of a path coefficient analysis, a highest positive direct influence was whiteness and a highest positive indirect influence was gelatinization start temperature. Positive indirect influence was high revealed gelatinization start temperature and amylose content, negative indirect influence was whiteness and gelatinization start temperature. In RT storage of Multiple regression equation of Toyo index based on physicochemical properties of unhulled rice, a highest coefficient of determination was revealed among five facters of whiteness, protein content, Mg/K ratio, amylose content and gelatinization start temperature. In cool storage of Multiple regression equation of toyo index based on physicochemical properties of unhulled rice, highest coefficient of determination was revealed among five facters of moisture content, amylose content, gelatinization start temperature, breakdown and setback.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.30 no.3
• /
• pp.217-222
• /
• 1985

The yield responses of three isogenic lines in plant type of paddy rice(open-, spread- and broom-type) as affected by combined treatments of transplanting densities (47.62, 22.22, 15.15, 11.11 and 8.33 hills per sq. meter) and rates of fertilizer application (0, 0.5, 1.0 and 1.5 folds of standard rate) were studied by using of the partial differentiations by planting density(D):df(D,F)/dD, fertilizer rate(F):df(D,F)/dF, and their interaction(DXF):d$^2$ f(D,F)/dDdF from the multiple regression polynominal equations. Under the condition of wider planting, the broom-type showed most prominent and sensitive responses in yield among others. Also the action of transplanting density in the broom-type were positive both at lower and higher densities. Under the lower densities, the broom-type represented positive actions both at lower and higher rates of fertilizer application. Whereas the interactions between the density and fertilizer rate under the lower densities were rather negative. To achieve the labor-saving by lower transplanting density(11-14 hills per sq. meter), the amount of fertilizer rates were estimated as 1.3-1.5 folds much of the standard in the open-type, whereas more than 1.5 folds in the broom-type. Thus, the potentials to absorb more amounts of fertilizer may explain the compensating function of the broom-type for equivalent yields of the standards at reduced transplanting densities.

• Korean Journal of Food Science and Technology
• /
• v.18 no.6
• /
• pp.458-467
• /
• 1986

This study was conducted to investigate the contamination level of some heavy metals for common restaurant meals in Seoul area and further to estimate the total dietary intake of heavy metals from the meals. The samples included seolong-tang (beef and rice soup) or galbi-tang (beef-rib soup), yeukkye-jang (spicy beef soup), doenjang-chigye-bab (boiled rice with soy paste stew), bibim-bab (boiled rice with assorted mixtures), and bibim-naengmyon (buckwheat vermicelli with assorted mixtures), which were separated into drained residues and fluids and determined for their heavy metal contents by atomic absorption spectrophotometry. The average concentrations of heavy metals in drained residues and fluids of 105 meal samples were 0.034 ppm, 0.017 ppm in Cd, 0.179 ppm, 0.073 ppm in Pb, 0.491 ppm, 0.308 ppm in Cu and 4.624 ppm, 1.403 ppm in Zn, respectively. The total amount of heavy metals per meal was $28\;{\mu}g\;Cd$, $145\;{\mu}g\;Pb$, $416\;{\mu}g\;Cu$ and $3654\;{\mu}g\;Zn$. The total dietary intake per day was estimated to give $84\;{\mu}g\;Cd$, $434\;{\mu}g\;Pb$, $1247\;{\mu}g\;Cu$ and $10960\;{\mu}g\;Zn$. Intake levels of Cd and Pb were higher than the daily intake limit established by FAO/WHO.