• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.1
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• pp.115-122
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• 1996

One of the most laborious work in rice farming is transplanting of rice seedling which has been required preparation of nursery bed and care of seedling during one month period. In this research, direct seeding in dry paddy(DS) and direct seeding in wet paddy(WS) were practiced to compare with traditional transplanting(TP) in Suwon. Growth stages in direct seeding were delayed as its planting time was about 21 days later than those of TP. Heading stage of direct seeding at Suwon was delayed about 9 days as compared to transplanting culture. Rice yield was not different between the seeding practises. Working-hour saving was about 17％(DS) and 28％(WS). Production cost of direct seeding was decreased 20％(DS) and 32％(WS), respectively. Amount of rice production per a unit working-hour in direct seeding could increase 14％(DS) and 39％(WS) compared to that of TP, respectively. Therefore, direct seeding could save significantly working hour and production cost without reducing rice yield. WS was more effective than DS in saving labor and production cost. Direct seeding was not efficient method in input of farming energy and agricultural chemicals.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.253-253
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• 2023

유역의 수량, 수질, 수생태, 지하수, 하천환경, 기후변화, 오염원, 하천 친수공간, 농업경작지 등 수자원 관점의 물순환의 범위를 넘어서 환경, 기후변화 적응, 경제성, 사회문화 등 다양한 분야를 포함한 통합적인 유역의 물관리 이슈와 문제점을 해결할 필요가 있다. 물순환 관리의 개념은 국토개발과 도시화에 따라 파생된 물순환 왜곡 및 그에 따른 제반 물문제(홍수량 증가에 따른 침수피해, 직접 유출량 증가에 따른 가용 수자원의 감소 등)의 해결을 위한 물관리 행위 전체로 볼 수 있다. 물순환 관리의 범위는 홍수량 감소를 위한 홍수관리, 가용 수자원의 증대를 위한 물 확보 등 물관리 전반을 포함해야 한다. 기존의 물순환 사업은 비점오염 관리에 중점을 두고 LID를 활용한 빗물 침투율 증대와 빗물 재이용 등의 관련 정책을 추진하였으나 이는 물순환 체계 전반을 다루고 있지 못하고 수질 개선에그 효과가 집중되었다. 따라서, 수량·수질·수생태·재이용 등을 종합적으로 고려한 물순환 관리에 대한 연구가 필요하며, 이를 통하여 개별적이고 시설물 중심인 기존 대책의 한계를 극복하고 통합물관리 관점의 물순환 건전성을 기반으로 유역의 안심공간 조성방안을 수립할 필요가 있다. 본 연구에서는 물순환 전반을 연계한 통합적인 물관리를 통하여 물 안심공간을 조성하기 위한 토대를 제시하는 것을 목표로 하며, 통합물관리 관점의 물순환 관련 데이터 수집, 유역별 물순환 수준의 진단 및 평가를 통하여 시범사업 모델을 마련하고, 사업에 따른 효과분석을 기반으로 중장기 추진계획 수립을 통한 실행력을 확보하는 것을 목적으로 한다.

• Korean Journal of Agricultural Science
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• v.26 no.1
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• pp.6-11
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• 1999

This experiment was carried out to estimate the appropriate seedling stand and to find out the factors of good establishment and the reason of the reduction of yield by water foxtail. The seedling stands was improved by the ice straw mulching and treading by the tracks of combine. The effect of mulching was higher than the treading. The appropriate seedling stands for example yield were estimated about 507 plants per $m^2$ and its yield was 24kg/10a. The higher density of water foxtail, the less the grain yield; 21.8% by 17 to 22 water foxtail stands per $m^2$ and 11.0% by 6 to 11 plants.

• The Korean Journal of Mycology
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• v.28 no.2
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• pp.93-96
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• 2000

To investigate the effect of inorganic nutrient supplement in oyster mushroom (Pleurotus ostreatus), we have conducted some study on cultural and growth characteristics of fruitbody formation and chemical composition of media and fruitbody. When supplemented with slow releasing fertilizer, contamination rate was not different from non-supplemented medium, days for incubation time and first pinhead were faster than non supplemented medium. And fruitbody yield and biological efficiency were increased $10{\sim}28%,\;7{\sim}20%$ respectively, but biological efficiency was decreased when increased supplement ratio. The chemical compositions (total carbon, total nitrogen, ammonia nitrogen, nitrate nitrogen, potassium and phosphate) of slow releasing fertilizer supple mented medium and fruitbody were compared with non-supplemented.

• Korean Journal of Weed Science
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• v.31 no.2
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• pp.167-174
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• 2011

Weed control using cover crops has advantages of agricultural and environmental aspects which prevent soil erosion, nitrogen supply, improving soil physical properties, reduction of nitrate leaching, organic supply and control of weed occurrence. In this study, we evaluated the inhibitory effects of cover crops on the weed occurrence, growth and yield of soybean in cover crop-soybean cropping system. The treatments were consisted of 4 different mulching system such as crimson clover (Trifolium incarnatum) residue, hairy vetch (Vicia villosa) residue, rye (Secale cereale) residue and Polyethylene plastic(P.E.) mulch with no mulch treatment (control). Three cover crops were grown throughout the winter and were cut in next spring. And then 13 days old soybean seedlings were transplanted in each treatment field on $4^{th}$ June. Crimson clover, hairy vetch and rye mulch treatments reduced weeds density compared to control (73.0%, 98.0% and 85.3% respectively), on $26^{th}$ May. However, weed inhibition rate of crimson clover mulch treatment was sharply decreased to 4.17% on $6^{th}$ August, while hairy vetch and rye mulch treatments were continued high weed inhibition rate with 87.6% and 72.0% respectively. There was no inhibition effect of perennial, winter annual and broadleaf weeds inhibition in crimson clover mulch treatment. Height of soybean in crimson clover, hairy vetch and P.E. mulch treatment was 6.9%, 20.2% and 22.0% higher than that of control. But height of soybean in rye mulch treatment was lower than control on $13^{th}$ July. At harvesting, yields of soybean were in order of hairy vetch mulch treatment${\fallingdotseq}$ P.E. mulch treatment > crimson clover mulch treatment ${\fallingdotseq}$ rye mulch treatment > control.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.3
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• pp.179-186
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• 2009

Relation between soil salinity and forage yield of five upland crops such as sudan grass, sesbania, barnyard grass, corn and soybean was studied in the three reclaimed lands of Korea during two years from 2007 to 2008. Although plant number emerged was obtained satisfactory by desalting treatment, further growth of crops was sharply affected by re-salting process according to soil drying. Soil salinity varied place by place and changed constantly, crop growth was differently responded to soil salinity according to the specific conditions of the reclaimed lands. In the Iweon reclaimed land with higher soil water conductivity and sandy soil texture, crop growth and yield sharply decrease with increase of soil salinity. Relation between soil salinity and crop growth and yield was well expressed as logarithmic function. Surface soil EC to reach at 50% of growth reduction to the tallest height of crops was $5dS\;m^{-1}$ for soybean, $6dS\;m^{-1}$ for corn and $7dS\;m^{-1}$ for sudan grass, sesbania, and barnyard grass by logarithmic function. In the Hwaong and Yeongsangang reclaimed lands with low soil conductivity and finer soil texture, plant growth response to salt stress was statistically vague by mixing of harmful influence from flooding and wet injury. However, it is observed that crop growth and yield on the place of lower salinity was better than crop growth on the place of higher salinity. It is accordingly concluded that flooding control during summer rainy season is vary important as well as desalting process for good growth of soiling and forage crops in the newly reclaimed land from tidal flat.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.3
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• pp.227-231
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• 1984

Chinese CGMS (Cytoplasmic-Genetic Male Sterility) is being transfered to Korean cultivars which will be used as CGMS maintainers. These maintainer lines along with the Chinese CGMS lines and their maintainer lines were crossed with another group of Korean cultivars which will be used as the fertility restorers, and their yield heterosis were examined. The yield heterosis was calculated as high as 113.0-221.1 % in terms of heterosis (F$_1$/Midparent) with the grand mean of 150.5%, and, 86.1-179.8% in terms of heterobeltiosis (F$_1$/better parent) with the grand mean of 125.3%. Among the female parent groups, Chinese mainteiners were the highest following by Chinese MS lines and the Korean maintainers were the lowest. Heterobeltiosis of yield components were 92.7%, 120.0%, 103.0% and 112.0% for number of panicles/unit area, number of grains/panicle, fertility per cent and 1000 grain weight, respectively. Path-coefficients of yield components to the yield were calculated. The highest one was number of grains per panicle ranging 0.8073-0.8649 followed by the 1000 grain weight ranging 0.2000-0.5032. The grain yield ratios to the grand mean were calculated in terms of combining ability. It was highest with the Chinese maintainers followed by Chinese MS lines and The Korean maintainers were lowest. This facts bring cautions to the breeding efforts to transfer the Chinese CGMS in to Korean maintainers.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.4
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• pp.345-352
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• 2011

Soil fertility different depend on application rate of manure and compost for many years. While each crop has different adaptability depend on soil fertility, crop and species or varieties should be chosen depending on the adaptability and productivity. These experiments were carried out to compare the five winter cereal crops for whole crop silage on growth, yield and feed value as affected by soil organic content. The rate of increase on no. of spikes at high fertile soil compared with medium fertile soil was sequently high Samhan (Oat's variety) > Cheongwoo (Wheat) > Gogu (Rye) > Youngyang (Barley) > Shinyoung (Triticale). The rate of decrease at low fertile soil compared with medium fertile soil was sequently high Youngyang > Gogu > Cheongwoo > Shinyoung > Samhan. The triticale was lower variation of no. of spikes as affected by soil organic content than that of other winter cereals. The variations of dry matter yield as affected by soil fertility was higher oat and barley and lower triticale. Forage yield of triticale was higher about 69 percent than that of barley at low fertile soil. Forage yield was the highest in triticale and the lowest in rye in all soil fertility. In high fertile soil, rate of increasing digestible dry matter (DDM) yield compared with medium fertile was high in Samhan and Youngyang. Rate of reduced DDM yield in low fertile soil compared with medium fertile was low in Shinyoung and Cheongwoo.

• Journal of the Korea Institute of Building Construction
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• v.21 no.3
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• pp.181-188
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• 2021

In this study, the various performance of dry cement mortar for Korean floor heating system depending on water-to-dry mortar ratios (W/DM) applied in project site was evaluated. According to the experiment conducted, the importance of mixing water for dry cement mortar was revealed by resultant performance or quality of the dry cement mortar for floor finishing by changing W/DM controlled in project site by workers. As the general trend, the flow was increased, and the unit volume weight was decreased with increasing W/DM. Additionally, compressive strength and drying shrinkage were significantly influenced by W/DM. Hence, it can be stated that the adding water for dry cement mortar should be managed precisely since excessively increased W/DM for workability improvement can cause performance degradation of floor mortar with the failures such as excessive bleeding, and severe segregation during the fresh state. As a summary of the study, to achieve a desirable performance of dry cement mortar, approximately 20 % of W/DM can be suggested to be managed in project site.

• Korean Journal of Weed Science
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• v.4 no.1
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• pp.19-25
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• 1984

Emergence, growth of weeds and growth, yields of rice (cv. Sam Seung Byeo) were determined at different transplanting times and nitrogen levels. Dominant weed species were Cyperus difformis, Rotala indica, Monochoria vaginalis, Cyperus serotinus, Sagiitaria pygmaea, Scirpus hotarui, and Fimbristylis miliacea. Number of weeds was increased in earlier transplanting time and but decreased in high nitrogen level. Dry weight of weeds was decreased with increase of nitrogen level at early transplanting time (May 26) but increased at nitrogen 8 or 16㎏/10a, Plant height, dry weight, leaf area index, and yield of rice were decreased as transplanting time was delayed but increased as nitrogen level increased. Yield reduction of rice due to weed competition was increased in earlier transplanting time and decreased in high nitrogen level.