• Korean Journal of Environmental Biology
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• v.18 no.3
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• pp.347-353
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• 2000

Standing crops of freshwater phytoplankton was studied from October 1998 to September 1999 in Hyendo, Maam, Jangam, and Napo of Kumgang River. Standing crops peaked in July in Hyendo $(39.5{\times}10^3Cells ml^{-1}), Maam (112.1{\times}10^3Cells ml^{-1}), and Jangam (125.5{\times}10^3Cells ml^{-1}), while in August in Napo (288.6{\times}10^3Cells ml^{-1}), respectively. The standing crops ranged less than 5,000 cells ml^{-1} in most of months in Hyendo and Maam, while more than 5,000 cells ml^{-1}$ throughout the year in Napo, Jangam's standing crops being intermediate. Total standing crops throughout the year increased with downstream; the standing crops of Napo was 9.6 times higher than that of Hyendo. The standing crops peaked from spring to early summer in Jangam and peaked in other seasons in Napo. The small centric diatoms Cyczotella spp., Stephanodiscus spp. and filamentous diatoms Aulacoseira spp. played an important role to form the peak of standing crops.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.4
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• pp.500-507
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• 2019

Objectives: The purpose of this study is to categorize farm types and analyze the cultivated area and labor input time for each crop over a year in order to decide farm type conducting for the hazard exposure assessment. Methods: Crops ranked within the top 45 by cultivated area in Korea were selected and 15 target crops that exposure assessment had been conducted for through the Rural Development Administration(RDA) pilot research projects were selected. Labor input time was based on data investigated through RDA research surveillance. If there was no data, data from Statistics Korea was used. Data from Statistics Korea was used for total cultivated area. Results: Crops were divided into 5 types: open field crops(Chinese cabbage, Corn, Ginger, Potato), fruits (Mandarin, Pear), green house crops(Cucumber, Lily, Oriental melon, Pumpkin, Tomato), livestock(Poultry), specialty crops(Ginseng, Oyster mushroom, Tobacco). The cultivated area for potato was the largest, and lily was the smallest among the crops. Labor input time over a year was the highest with oyster mushroom and the lowest with pear. Total labor input time by crops was the highest with mandarin and the lowest with Chinese cabbage. Conclusions: To evaluate hazard factors of farm work, it's essential that crops and tasks be classified based on the size of farmers and working hours by farm type. Therefore, the priority of management should be determined based on the cultivated area and total labor time, but the characteristics of tasks in each crop should also be considered.

• 한국약용작물학회:학술대회논문집
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• 2008.11a
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• pp.181-182
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• 2008

• 한국약용작물학회:학술대회논문집
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• 2008.11a
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• pp.133-134
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• 2008

• 한국약용작물학회:학술대회논문집
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• 2008.11a
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• pp.143-144
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• 2008

• Journal of Plant Biology
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• v.22 no.3
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• pp.59-62
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• 1979

Distribution and standing crops of seedling and sapling as undergrowing tree were investigated in a Pinus rigida forest. The relative light intensity(RLI) on the ground level was 3.9∼59.3% which indicates a wide range. Under this range of RLI seedlings and saplings distribute well in the stand. Eight trees were selected from the stand, then measured dry weight of stem, branches and leaves using thestratified clip technique. A possible relationship between the diameter at the bottom of the tree (Do) and standing crops was investigated. As Do increased from 0.8cm (T1) to 7.2cm (T8), the standing crops also increased from 42.6g to 7,410.4g. Since semi-log values between Do and standing crops clearly indicates a straight line, there is close relationship between these two factors. Therefore it is possible to estimate the standing crops of seedling and sapling by measuring Do. Productive structure shows that phytosynthetic layer is located above the 1/2 height of the tree and maximum photosynthetic layer apperars on 2/3 level in height.

• Korean Journal of Organic Agriculture
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• v.17 no.1
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• pp.1-17
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• 2009

The production of bio-energy crops is a major research project in the emphasizing the "low carbon green growth" strategy. For this, the possibility of the introduction of the new energy crops improve the agricultural income from fanning must be diagnosed. This study describes the level of agricultural income per unit area by cropping system based on the income of crops in the field. Especially, we have chosen the southern part attracting the attention in the possible area of the bio-energy crop production. This study consists of five chapters. Chapter I is the introduction. Chapter II is on the status of the southern part cropping system and the analysis of the economic value. Chapter III is on the economic value analysis introducing new bio-energy crops. Chapter IV is on the comparative analysis for the economic value of the croping system introducing new bio-energy crops. Chapter V is the conclusion.

• 한국약용작물학회:학술대회논문집
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• 2010.10a
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• pp.161-162
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• 2010

• Korean Journal of Agricultural Science
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• v.40 no.2
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• pp.169-176
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• 2013

The price and revenue of rice are expected to decrease due to increasing rice imports, decreasing consumption and the discontinuance of the government's rice procurement. This degenerating profitability is leading to a rise in the cultivation of upland-crops such as beans, fodder crops and fruits in paddy fields. However, there is a lack of research on the selection of rice substitute crops which are adaptable to the relevant region through profitability analysis. This research, therefore, analyzed investment profitability of rice substitute crops for Cheorwon-gun area in Kangwon province. The study applied net present value (NPV) and internal rate of return (IRR), which fit for mutually exclusive investments that make one selection to the exclusion of other crops. Target crops are green house plants in Cheorwon-gun area. Financial analysis showed paprika and cucumber have investment feasibility for automated vinyl greenhouses and conventional plastic greenhouses respectively.

• 한국약용작물학회:학술대회논문집
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• 2008.05a
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• pp.286-287
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• 2008