• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.4
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• pp.243-249
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• 2019

A barley(Hordeum vulgare L.) cultivar 'Youjin' with hooded spike type having good silage quality was developed at National Institute of Crop Science, RDA in 2016. 'Youjin' showed both high yielding and cold resistance through the preliminary and advanced yield trials(PYT, AYT) from 2012 to 2013. We conducted regional yield trials(RYT) of 'Youjin' in six locations around Korea for three years from 2014 to 2016. It had erect plant type, growth habit of II, the green leaf and hooded awn type. In the paddy field its heading date was April 24 and the maturing date was May 25. Plant height was 99 cm and the number of spikes per ㎡ was 696. It has high rate of leaf blades, resistance to BaYMV(Barley Yellow Mosiac Virus) and good winter hardiness. The average dry matter of Youjin was about 17.2 MT ha^-1 in the field. And feed quality of 'Youjin' was 10.6% of crude protein content, 24.8% of ADF(Acid Detergent Fiber), 43.5 % of NDF(Neutral Detergent Fiber), 69.1% of TDN(Total Digestible Nutrients). And also 'Youjin' had grade I of silage quality.

• Korean Journal of Environmental Agriculture
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• v.32 no.3
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• pp.179-184
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• 2013

BACKGROUND: Accurate estimates of total direct $CH_4$ emissions from croplands on a country scale are important for global budgets of anthropogenic sources of $CH_4$ emissions and for the development of effective mitigation strategies. Methane production resulted by the anaerobic decomposition of organic compounds where $CO_2$ acts as inorganic electron acceptor. This process could be affected by the addition of rice straw, water management and rice variety itself. METHODS AND RESULTS: Rice (Oryza sativa L. Japonica type, var Samkwangbyeo) was cultivated in four plots: (1) Nitrogen-Phosphorus-Potassium (NPK) ($N-P_2O_5-K_2O$:90-45-57 kg/ha); (2) NPK plus 3 Mg/ha rice straw (RS3); (3) NPK plus 5 Mg/ha rice straw (RS5); (4) NPK plus 7 Mg/ha rice straw (RS7) for 3 years (2010-2012) and the rice straw incorporated in fall (Nov.) in Gyeonggi-do Hwaseong-si. Gas samples were collected using the closed static chamber which were installed in each treated plot of $152.9m^2$. According to application of 3, 5, 7 Mg/ha of rice straw, methane emission increased by 46, 101, 190%, respectively, compared to that of the NPK plot. CONCLUSION(S): We obtained a quantitative relationship between $CH_4$ emission and the amount of rice straw applied from rice fields which could be described by polynomial regression of order 2. The emission scaling factor estimated by the relationship were in the range of IPCC GPG (2000).

• Korean Journal of Environmental Agriculture
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• v.4 no.1
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• pp.18-24
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• 1985

A pot experiment was conducted to study the influence of potassium and cesium carrier on the uptake of radionuclide $Cs^{137}$ which is an element released usually from nuclear facilities, by paddy rice upon prolonged cropping of contaminated soils. The results are summarized as follows: 1) Visual toxic symptoms on the growth of rice plant due to treatment of radioactive cesium were not observed up to $20 {\mu}Ci/10Kg$ soil in a pot. 2) The yield and potassium content in rice plant were increased with potassium application, while the reverse was true for the calcium and magnesium. The addition of potassium to the soil markedly reduced $Cs^{137}$ uptake by rice plant but the addition of Cs carrier increased $Cs^{137}$ uptake. 3) Potassium and $Cs^{137}$ showed uniform distribution in all parts of plant and the contents of these two elements were high in the stems and leaves, and low in the heads. The ratio of $Cs^{137}$ to K was, however, not uniform in all parts of a plant. It was shown that this ratio was higher in the seed part, that is, chaff and hulled grain than in the leaves and stems. 4) $Cs^{137}$ absorption rate in rice plant was remarkably reduced with increase of potassium application and it was ranged from $0.02{\sim}0.47%$ in potassium non-treated plot to 0.01∼0.04% in plot treated with a concentration of 16Kg/10a. 5) The amount of $Cs^{137}$ and potassium uptake of rice plant depended on soil type. Uptake of $Cs^{137}$ by rice plant was higher in the soil with low pH and potassium content. The $Cs^{137}$ uptake by rice plant decreased as the potassium content and pH of soil was increased, but $Cs^{137}$ uptake increased when CEC and clay content in soil was high.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.4
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• pp.330-336
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• 1984

These studies were aimed to find out the representative values of physico-chemical properties in Korean soils and to serve the basic informations to improve the soil properties for increasing the soil productivity. By the results of detailed soil survey, 14 physico-chemical properties (soil texture, moisture characteristics, organic matter content etc) were collected from 315 series of soils except Cheju soils, computerized the simple mean and the distributed area by weighted mean values with grouping of land use, drainage class and soil type. The results were as follows; 1. Simple mean values within the efficient soil depth in whole country soils were clay 20.0%, organic matter 2.03% and CEC 10.3me/100g. But weighted mean values with land area belonged to the same soil series were clay 18.0%, OM 1.85% and CEC 8.6me/100g. 2. Mean values of paddy soils weighted by area were clay 19.7%, OM 2.0% and CEC 9.1me/100g but those of upland soils were 17.9%, 1.8% and 8.1me/100g and forest soils were 16.7%, 1.8% and 8.6me/100g respectively. 3. Weighted mean values of moderately well soils with covered area were clay 18.9%, organic matter 1.7%, CEC 8.4me/100g but those of imperfectly drained soils were 21.3%, 2.2% and 9.5me/100g, and those of poorly drained soils were 15.1%, 1.8% and 9.9me/100g respectivcly. 4. Simple mean and area weighted mean values of clay content, pH, organic matter contents, cation exchange capacity and base saturation were calculated by the types of paddy and upland.

• Journal of Wetlands Research
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• v.7 no.1
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• pp.107-117
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• 2005

Soil erosion is influenced from a variety of factors such as rainfall distribution, soil type, land use, etc. This paper is aimed at analyzing the soil erosion hazard zone in cropland. RUSLE was used for an analysis of soil erosion amount, and for the spatial data of basin, soil erosion amount was calculated by extracting the respect topography space related factors of RUSLE using DEM, Landuse, Soil map as base map. This paper is targeting at the watershed of Gyeongan stream in Gyeonggi-do The result of an analysis of soil erosion amount showed that soil erosion occurred in the order of crop field(1210) planting area, orchard(1220), non-adjusted paddy fields(1120), and adjusted paddy fields(1110), and also the average soil erosion in these planting areas has the most amount in crop field planting area. As a result of analysis on soil erosion hazard zone of farm land by classifying it into 5 classes using the result of that result of analysis on the amount of soil erosion, in case of Class 5 in which the hazard of soil erosion is the highest, approximately 72.5ha that corresponds to 2.4% of the total farm land was decided as erosion hazard zone. For this erosion hazard zone, it was analyzed that dry field crop planting area was 72.4ha and orchard was 0.1ha, and Class 5 hazard zone did not appear in other farming areas. Also, it showed that Class II(1~50ton/ha/yr) area had the most ratio of the entire farm land, i.e., 70.2%, regardless of land use state. According to the result of analysis on soil erosion hazard zone of farm land by classifying it into 5 classes, the Class V has the highest soil erosion hazard, approximately 72.5ha that corresponds to 2.4% of the total farm land was estimated as an erosion hazard zone. This erosion hazard shows 72.4ha in dry field crop planting area, 0.1ha in an orchard, but the highest hazard zone, the Class V was not shown in other farming areas. Also, it showed that Class II area had the most ratio of the entire farm land, i.e., 70.2%, regardless of land use state.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.4
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• pp.301-307
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• 2017

A new barley(Hordeum vulgare L.) cultivar 'Dachung' having high forage yielding and good silage quality was developed at National Institute of Crop Science, RDA in 2015. This cultivar was derived from a cross of the 'Sunwoo' and 'Keunalbori1ho' in 2002. And it's promising line showed both high yield and lodging resistance through the preliminary and advanced yield trials(PYT, AYT) at Iksan from 2010 to 2012. It was designated as the 'Iksan479'. 'Iksan479' was conducted to regional yield trials(RYT) in six locations around Korea for three years from 2013 to 2015. And it was released as the name of 'Dachung'. It has erect plant type, growth habit of IV and green leaf. In the paddy field its heading date was April 24 and maturing date was May 26, same day with 'Youngyang'. Plant height of 'Dachung' was 99cm. Dachung's spikes per $m^2$ was 625. It has high rate of leaf blades, resistance to BaYMV(Barley Yellow Mosiac Virus) and better winter hardiness than that of 'Youngyang'. The average dry matter of 'Dachung' was about $11.9ton\;ha^{-1}$ in paddy field. And average feed quality of 'Dachung' was 9.0% of crude protein content, 31.3% of ADF (Acid Detergent Fiber), 54.4% of NDF (Neutral Detergent Fiber), 64.0% of TDN (Total Digestible Nutrients). 'Dachung' had grade I of silage quality. This cultivar would be suitable for the area above the daily minimum temperature of $-8^{\circ}C$ in January in Korean peninsula.

• Korean Journal of Weed Science
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• v.12 no.2
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• pp.144-157
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• 1992

The study was conducted to compare the interprete methods and examine the feasibility of mixture use of oxyfluorfen and bensulfuron in controlling principal Paddy weeds, annuals and perennials. Application ratio of both chemicals were obtained from the combinations of 5 levels(0, 5, 10, 15, 20 g ai/ha) of each chemicals, respectively. All the treatments were applied at 5 days after transplanting and water was maintained at 3.0cm in depth. Shoot fresh-weight of weeds was assessed at 35 days after treatments. Data obtained was analysed by Colby, Isobole, Calculus, Regression and EQM method, respectively. The results from the analysis of variance on the principal weeds treated with oxyfluorfen and bensulfuron showed significant interactions at 1% level on both Echinochloa crus-galli and Eleocharis Kuroguwai, and total species at 0.5% level on both Potamogeton distinctus and Cyperus serotinus, but non significant on Scirpus juncoides and Sagittaria pygmaea. Thereafter, the results of the models applied to Echinochloa crus-galli, Eleocharis kuroguwai and total species were as follows ; 1. The Colby method gave values nearly identical to regression estimate method (both multiplicative models) as provided by Akobundu et al. The Colby method and Regression method indicated synergistic toward Echinochloa curs-galli, and total species, but antagonistic toward Eleocharis kuroguwai. 2. The Isobole method shows synergism on Echinochloa crus-galli at $ID_{50}$, and total species at $ID_{60}$ on Eleochari kuroguwai. 3. The Calculus method gave positive signs for the first differentiation and negative signs for the second differentiation except for some rates on Echinochloa crus-galli and total species, but reverse on Eleocharis kuroguwai. These result does not agree with the observed values. 4. ${\theta}$ value from the EQM method was greater than one at all combinations. This result was quite different from those of other methods. 5. The various models did not show the same results, but mixture of oxyfluorfen and bensulfuron tend to have synergistic effect. Weeding effect also was high. Treatment in terms of two chemical combination was expected to reduce rates, and to enhence weeding efficacy compared with single treatment.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.429-439
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• 1999

Potentiometric titration data were collected for some humic acids purified from Korean upland and paddy soils over a range of pH (3.0 - 11.0) with $NaNO_3$ background electrolyte concentrations (0.01, 0.10, 0.50 and 1.00 M). The data were applied to model A and V which included both intrinsic heterogeneity of humic materials and electrostatic interaction influences on binding sites. The elemental analysis were conducted for various type of humic samples. The $E_4/E_6$ ratio proposed negative correlation with the total carboxyl groups ($r^2$= 0.9988). The charge ($cmol_c\;kg^{-1}$) on the humic acids became more negative as the ionic strength increased. In both continuous and batch titrations, the ionic strength effect was greater in Namweon series (pH 6.39) than others at pH 5.00. The effect of ionic strength on surface charge appears to be greater in batch titrations. This could suggest that continuous titrations do not represent an equilibrium state and the effects of electrolyte concentration was not fully realized during the course of titrations. Both models described experimental data obtained from continuous and batch titrations well over a range of ionic strengths. Model A is more simpler than model V but adaptes more fitted parameters. Thus, the observed change in apparent binding constants with surface charge is regarded solely due to electrostatic influences rather than functional group heterogeneity. However, Model V is more mechanistically realistic in a number of discrete ligand binding sites.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.371-378
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• 2013

Various microorganisms live in soil, of which those colonizing rhizosphere interact with nearby plants and tend to develop unique microbial communities. In this study, we isolated diverse actinomycetes from rhizosphere of rice (Oryza sativa L.) cultivated in fertilized (APK) and non-fertilized (NF) paddy soils, and investigated the diversity and antimicrobial activity of them. Using four kinds of selective media, 152 isolates were obtained from the soil samples and identified by determining 16S rRNA gene sequence. All of the isolates showed 99.0%~100.0% similarities with type strains and were classified into six genera: Dactylosporangium, Micromonospora, Kitasatospora, Promicromonospora, Streptomyces and Streptosporangium. Most of the isolates, 143 isolates, were classified into the genus Streptomyces. Additionally, many isolates had antimicrobial activity against plant pathogens, especially Magnaporthe oryzae (rice blast pathogen) in fungi. These findings demonstrated that rice rhizosphere can be a rich source of antagonistic actinomycetes producing diverse bioactive compounds.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.2
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• pp.157-165
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• 2005

The purpose of this study is to examine the relationship between land use patterns of riparian zones and water quality in the Geumho River watershed. A GIS database included digital land use maps (1:25,000), stream network extracted from digital topographic maps (1:5,000) and riparian zones maps by multi-buffering method. Pearson's correlation analysis was used to explain the relationship between the environmental conditions of a 30 meter buffer strip on each side and water quality. According to the result of investigation of riparian-level land use patterns, sub-watersheds on the lower Geumho River including Daegu metropolitan city were mainly developed as urban area such as residential, commercial and industrial ones, while sub-watersheds on the middle Geumho River and the main course of Nakdong River, agricultural ones such as a paddy, a dry field and an orchard. Meanwhile, the area-rate of riparian forests which play an important role in filtering nitrogen, phosphorus and sediment was estimated below the average 16%. The proportion of urban area in a 30 meter riparian bufferstrip had a negative correlation with water quality in each sub-watershed. But the proportion of forest area had a positive correlation with water quality. Henceforth, it is necessary to establish landscape planning for preparing and restoring the riparian buffer zones, concerning land form, soil type, the present land use pattern and economic aspects.