• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.77-84
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• 2001

To increase the utilization of soil survey results, classification of morphological types of paddy soils which was consisted of land-form, texture, and drainage classes etc. was attempted as an interpretive classification system. The paddy soils could be classified into 37 types. Among the types, the "Lfi(Fine loamy textured semi-wet paddy on local valley and fans)" acreage of about 224 thousand ha, "Lfd(Fine loamy textured dry paddy on local valley and fans)" 160 thousand ha. "Lmi(Coarse loamy textured semi-wet paddy on local valley and fans)" 112 thousand ha, and "Lkd(Loamy skeletal dry paddy on local valley and fans)" 93 thousand ha, respectively were the dominant types. The possibility of double cropping, plastic film house, green manure cropping etc., and that for soil managements such as application of raw straw or compost, deep plowing or adding fine earth materials, mole drainage, susceptibility to erosion or reduction injury etc. for each types were recommended.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.6
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• pp.361-371
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• 2002

Multifunctionality of agriculture has been an important international issue in terms of environmental benefits and public concerns. We calculated soil loss mass in national basis using the USLE, and attempted to evaluate its economical benefits by replacement cost method. Soil loss mass ranged from 1.4 to $18MT\;ha^{-1}\;yr^{-1}$ was fairly fitted to measured values for 13 cropping systems. In national basis, the factors in USLE were evaluated as: 429.4 for rainfall and runoff factor. R, 0.15 for soil erodibility factor, K, 1.72 for topographic factor, LS, 0.275 for cover and management factor, C, and 0.856 for support practice factor, P. The soil loss estimated from upland farming using the USLE was $26.1MT\;ha^{-1}\;yr^{-1}$, but soil loss from the bare soil was $110.8MT\;ha^{-1}\;yr^{-1}$, the ratio of soil loss from upland farming to bare soil was 23 percents. Function of reducing soil loss in comparison with the bare soil was $84.7MT\;ha^{-1}\;yr^{-1}$, of which national soil loss mass was 62.6 million MT per annum in south Korea. Agriculture economic replacement cost of soil loss reduction was 497 billion Wons(398 million dollars) for the cost of upland soil dressing. For conservational purposes to increase the environmental benefits of upland farming, the agricultural practice including contour, strip cropping, terracing and division ditches should be implemented.

• Journal of Wetlands Research
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• v.15 no.1
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• pp.71-78
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• 2013

An exceptional case of inhabitation of a Sphagnum sp. was firstly confirmed at abandoned paddy terrace (APT) wetland in Ansan. Water sampling for analyzing of physicochemical conditions including nutrients such as NP, $Ca^{2+}$ and $Mg^{2+}$ was performed and the vegetation map for distribution of Sphagnum sp., topographical map, and flora list for companion species were made at field in June 2011. From the results, the Sphagnum sp. in the study site was identified as S. palustre and it covered about 8% of the wetland cover of 3,200 $m^2$. Most distributions of S. palustre were observed at tussock structures as micro-topography by sedges and grasses within a wetland (74%) and the shaded slope area under Pinus densiflora's canopy in wetland boundary (26%). Despite that APT in Ansan is relatively lower wetland in altitude than high moors, the contents of calcium ($0.45{\pm}0.2$) and magnesium ($1.48{\pm}0.6$) ion which are critical limiting factors for Sphagnum spp. were very low levels as well as NP ($PO_4$-P, $0.02{\pm}0.0$; $NO_3$-N, $0.25{\pm}0.3$; $NH_4$-N, $0.06{\pm}0.1$) and it could enable the inhabitation of S. palustre in lower APT.

• Journal of Wetlands Research
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• v.15 no.3
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• pp.329-337
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• 2013

This study was performed to evaluate the temporal and spatial variations of the water quality at stream flowing into the Suncheon bay in Suncheon city from October 2008 to August 2009 and to estimate the pollutant sources from the streams using multivariate analysis. Water qualities from Seo stream, Dong stream, Ok stream were evaluated as I grade(very good) that compared to the Water Quality Standard. But Haeryong stream and inlet site of Suncheon Bay in BOD were evaluated as a little bad and fair. Water quality at the stream flowing into the Suncheon Bay was could be explained up to 92.8% by three factors which were included in loading of nutrients, organic matter and total coliform group by the allochthonous matters(53.7%), Topographic Factors(25.0%), seasonal variation(14.2%). The concentrations of total nitrogen and phosphorus at sewage treatment plant and organic matters at Haeryong stream were higher than that of others, respectively. From principal component analysis and factor analysis, it could be suggested that it is very important to make an effort to reduce the nutrients and organic matters from sewage treatment plant and Haeryong stream to be in good conservation of the Suncheon bay.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.1
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• pp.31-38
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• 2009

Purpose: This study was to evaluate corneal topography, contrast sensitivity and ocular response of a RGP, back surface aspherical contact lens compared with a spherical contact lens. Methods: A total 37 subjects were fitted with a spherical lens in right eye and an aspherical in the left eye and were evaluated for changes in corneal topography and contrast sensitivity over a 2-month period. Results: Thirty-four of 37 subjects completed the 2-month study. The corneal topography did not show differences between spherical and aspherical RGP lenses. The eyes fitted with the aspherical lenses demonstrated a greater reduction in contrast sensitivity compared with their spherical counterparts under photopic condition. Subjects preferred comfort and ocular responses provided by the spherical lens. Conclusions: Corneal topography when comparing spherical and back surface aspherical RGP lenses did not show any significant difference in the subjects. Spherical RGP lens yields better contrast sensitivity and preference than aspherical RGP lens at photopic condition. Further investigation of aberrations induced by contact lens design is warranted to explain the observed differences in visual performance.

• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.567-582
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• 2015

Botrytis cinerea infects stems, leaves and fruits of greenhouse tomato and can cause serious economic losses. This study was conducted to develop organic farming control method against tomato gray mold. Twenty two organic farming materials including mineral and plant extracts were screened for the suppressive activity against Botrytis cinerea, in vitro and in vivo. Among the organic farming materials, sulfur, copper, Chinese twinleaf extract and rhubarb extract decreased by 51.7-90% of the spore germination of Botrytis cinerea. Also, gray mold incidence was reduced more than 90% on tomato stems by treating sulfur, seaweed extracts, rhubarb root extracts and Chinese twinleaf extract. After the selected four organic farming materials were applied on tomato cultivated in greenhouse, their control effects against the tomato gray mold were tested. When the water soluble sulfur was foliar-sprayed on the tomato leaves infected by artificial inoculation with spore suspension of Botrytis cinerea, it showed 87.9% of control value. Also, control activity of the water soluble sulfur was paralleled with chemical fungicide, diethofencarb+carbendazim. The above mentioned results indicate the sulfur formulation can be used as chemical fungicide alternatives for controlling tomato gray mold in the greenhouse.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.789-799
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• 2014

We have analyzed the effect of planting site (elevation) and direction of fruiting on the frost damage (tolerance to transparent skin and blemishes) of persimmon (Diospyros kaki Thunb) 'Fuyu' fruit subjected to the early fall frost (November 2, 2012) in environment-friendly orchards of Changnyeong and Changwon (Gyeongsangnam-do Korea). In Changnyeong, the direction of fruiting showed a significant effect on the fruit weight and the fruit width (p<0.01), and the fruit firmness (p<0.05) while the planting site (elevation) did a highly significant effect on the fruit width and the frost damage (p<0.01), and fruit length (p<0.05). In particular, severe frost damage of fruit (15.2%) and leaves (about 90%) was observed in the plants located in the low elevation area of orchard. The damaged fruit had an transparent skin color and/or blemishes. In Changwon, there was no effect of the planting site and the direction of fruiting on the frost damage, and the fruit characteristics except the fruit width having been related to the planting site (p<0.05). So, the main effects for the fruit frost damage was a terrain factor around the orchards.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.773-787
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• 2014

Bacterial pustule of soybean caused by Xanthomonas axonopodis pv. glycines is one of the most prevalent bacterial diseases in many areas where soybeans are grown. This study was carried out to evaluate the effect of cultivars, sowing date and cropping system on the suppression of soybean bacterial pustule in the field. One hundred soybean cultivars were screened for disease resistance against bacterial pustule in naturally infested field. Among them, fourteen cultivars including 'Pureun' were found to be high resistant. And thirty cultivars showed to be moderate resistant(less than 3% of diseased leaf area). When Soybean cultivar 'Taekwang' were sown in four different dates, May 25, June 5, June 15, and June 25, at 10 day-interval in Milyang, the diseased leaf area of bacterial pustule was 23.3%-25.7%, 14.7%-18.0%, 10.7%-12.8%, and 1.0%-2.7%, respectively. The lowest percentage of diseased leaf area was recorded in the plots sown on June 25, whereas the highest percentage of diseased leaf area was recorded in the plot sown on May 25. As sowing time was delayed, incidence of soybean bacterial pustule found to be comparatively reduced. From December in 2006 to June in 2007, we surveyed the pathogen population of soybean bacterial pustule in five cropping upland soils where soybean was cultivated. The survey result showed the bacterial pustule pathogens were detected from the all cropping soils. The pathogen populations of soybean bacterial pustule in soybean-barley and soybean-garlic cropping soil were significantly lower than that of the other cropping soils. In addition, the incidence of soybean bacterial pustule was decreased under the two cropping systems.

• 한국해양학회지
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• v.1
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• pp.37-48
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• 1971

Observations of water temperature, salinity, pH and transparency of the Ko-ri sea area were made between May 1969 and April 1970. A seasonal thermocline was well defined in August, strongly isolating the warm serface water(19-22$^{\circ}C$) from the cold bottom water (14-17.5$^{\circ}C$) introducing from the open sea. In February the coldest isothermal water (11$^{\circ}C$) occurred. In the warm months(May- September), the salinity patterns show great variations with the coastal run-off During the cold months(December-April) the highest isohaline water (35 ) occurred. Annual ranges of surface and bottom pH values were 7.8-8.4(averaging 8.27) and 7.9-8.4(averaging 8.26), respectively. The transparency was greatest (6.0-7.0m) during winter and spring months and least (1.2-2.5m) during summer months.

• Journal of Animal Environmental Science
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• v.16 no.3
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• pp.245-252
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• 2010

Disposal methods of managing carcass in Korea livestock production systems include burying, digesting, rendering, carcass dumping to manure pile, dead animal disposer and mini-incinerator. Burying was usually the most practical method of carcass disposal in our livestock farms. Burying, carcass dumping to manure pile, dead animal disposer and mini-incinerator may have environmental regulatory and economic liabilities when used as a means of carcass disposal. In many cases in this survey, these disposal methods offer a poor choice for the producer due to individual site conditions, geology, cost, air emissions, rendering plants. A survey questionnaire that addressed the issues to livestock producers was prepared. The questionnaire addressed two main topics as follows: 1) types of livestock and generation amounts of carcass 2) Number of breeding animals and disposal methods of livestock mortality. A total of 36 livestock producers were interviewed. The results of obtained in this survey were summarized as follows: The number of breeding poultry, swine, beef cow and dairy cow was 251,000, 2,600, 142 and 92 heads per year and the generation amounts of annually carcass was 0.46, 15.32, 0.36, 1.36 tons per year of each poultry, swine, beef cow and dairy cow farms, respectively. The disposal methods of carcass were burying (42%), carcass dumping to manure pile (36%), rendering (8%), incineration (6%), digesting (6%), carcass disposer (2%), respectively. These results can be used as basic information to establish the standard of carcass composting facility.