• Title/Summary/Keyword: green crops

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Seasonal Changes of the Phytoplankton Community in the Imjin River (임진강 수계의 식물플랑크톤 군집의 계절적 변화)

  • Yoon, Sook-Kyung;Lee, Kyung
    • Korean Journal of Ecology and Environment
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    • v.35 no.2 s.98
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    • pp.111-122
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    • 2002
  • Seasonal changes of the phytoplankton community was investigated from July 2000 to April 2001 at five stations in the Imjin River. A total of phytoplankton were composed of 193 taxa, belonging to 5 divisions, 145 species, 28 varieties, 1 form, 19 unidenfitied species. Of those, the diatoms and green algae were present during the investigation periods more frequently than the other taxa. The phytoplankton standing crops varied from $89{\times}10^3\;cells/l$ at station 1 in October 2000 to $8,825{\times}10^3\;cells/l$ at station 3 in April 2001. Throughout the investigation periods, at station 1, there was low in the size of phytoplankton standing crops at large. Otherwise, at station 2, staion 3 and station 4, we could see the maximum of phytoplankton standing crops in July 2000 and then phytoplankton standing crops decreased and it reached to the minimum in January 2001, and after then, it increased again. But exceptionally, we could see the maximum of phytoplankton standing crops in April at station 3. And also, at staion 5, we could see the similar variation pattern of phytoplankton standing crops at station 2, station 3 and station 4 with a little differences in seasonal variation pattern of phytofllankton standing crops. The major dominant species were Achnanthes minutissima, Anabaena sp., Aulacoseira ambigua, A. granulata, A. granulata v. angustissima, Cymbella affinis, Cylindrotheca closterium, Diatoma vulgare, Merismopedia glauca, Stephanodiscus hantzschiif. tenuis.

Computer Simulation of Lower Farmland by the Composition of an Agrophotovoltaic System (영농형 태양광 발전 시스템 구성에 따른 하부 농지 일사량의 전산모사 연구)

  • Kim, DeokSung;Kim, ChangHeon;Park, JongSung;Kim, ChangHan;Nam, JaeWoo;Cho, JaiYoung;Lim, CheolHyun
    • New & Renewable Energy
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    • v.16 no.1
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    • pp.41-46
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    • 2020
  • The share of agrophotovoltaics in the "renewable energy 3020", which is the Korean government policy for revitalizing new and renewable energy, is increasing gradually. In this study, the distribution of solar radiation received by crops growing on virtual farmland under a range of conditions, such as module height, module angle, shading ratio, and module type, was quantified and analyzed using an Ecotect program, which allows insolation analysis during the period from spring to fall. As the module angle increases, transmissive modules increase the amount of solar radiation delivered to the lower farmland. In addition, the difference between 3x12 Cell Type and 4x9 Cells Type, which are types of photovoltaic modules used in practice, was found to be small. The analysis results can be used as a design standard for the future establishment of agrophotovoltaic systems.

Comparing the susceptibilities of green peach aphid populations against several insecticides

  • Min, Ji-Hyun;Yoon, Heon;Kwon, Hay-Ri;Yu, Yong-Man;Youn, Young-Nam
    • Korean Journal of Agricultural Science
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    • v.44 no.3
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    • pp.348-358
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    • 2017
  • The green peach aphid, Myzus persicae, is one of the most serious insect pest and a vector for a multitude of viral diseases to many crops, vegetables, ornamentals, and fruit trees in the world. A large number of aphids can reduce plant vigor and cause defoliation. Many insecticides have been developed and applied to control the green peach aphid. However, this aphid has displayed a remarkable ability to establish resistance to almost every insecticide. We treated 5 different insecticides registered for M. persicae on pepper leaves and investigated the effects of the insecticides by measuring the time it took to achieve 90% control of the aphids. Acetamiprid worked faster than any other insecticides while cyantraniliprole showed the slowest insecticidal effect. Pymetrozine, pyrifluquinazon, and spirotetramet provided 90% control within similar time. Iwol population's control value was higher than any other populations 24 hours after treatment. When five different unregistered insecticides for M. persicae were treated on pepper leaves, no insecticidal effect was found for gamma-cyhalothrin and novaluron and spinosad showed an insecticidal effect of up to 70% in Iwol population only. Although chlorfenapyr and dinotefuran were not registered for M. persicae, their insecticidal effects were found to be 90% or higher.

Environmental Studies in the Lower Part of the Han River -VII. Long Term Variations and Prospect of the Phytoplankton Community- (한강하류의 환경학적 연구 -VII. 식물플랑크톤군집의 장기간 변화와 전망-)

  • Lee, Jin-Hwan;Jung, Seung-Won
    • ALGAE
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    • v.19 no.4
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    • pp.321-327
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    • 2004
  • The literature review on the dynamics of the phytoplankton communities in terms of species composition, standing crops, abundant species and dominant species in the lower part of the Han River from 1940s to 2000s was conducted for the prospective prediction of their succession patterns. Total of 326 taxa were identified and they belonged to 47 blue-green algae, 139 green algae, 12 euglenoids, 126 diatoms, 6 din flagellates and 2 silicoflagellates. Composition of phytoplankton communities were 83.6% diatoms, 10.5% blue-green algae and 5.3% green algae in the middle of 1960s, whereas those were 43.2% diatoms, 40.7% green algae and 13.6% blue-green algae in the 1990s. Before 1990s, Synedra ulna, Melosira varians, Cymbella tumida, Synedra acus, Cymbella ventricosa, Navicula cryptocephala, Nitzschia palea, Aulacoseira granulata, Gomphonema parvulum and Cymbella affinis were most frequent, while those after 1990 were Asterionella formosa, Asterionella gracillima, Aulacoseira granulate, Aulacoseira granulata var. angustissima, Chlorella vulgare, Fragilaria crotonensis and Synedra ulna. Phytoplankton blooms were frequent from winter to the late spring and rare in summer due to heavy rain and discharge. Seasonal variations of the dominant species were fairly obvious; Asterionella gracillima and Aulacoseira granulata in spring, Aulacoseira granulate and Aulacoseira granulate var. angustissima in summer and autumn, Asterionella gracillima and Stephan discus hantzschii in winter. Recently blue-green algae, Microcystis, Aphanocapsa, Dactylococcopsis have been more abundant than those of the previous reports. Based on the current situations, Stephan discus hantzschii f. tennis, Asterionella gracillima, Aulacoseira granulate and blue-green algae will be more abundant and blooms of those species will be more frequent.

Studies on lead uptake by crops and reduction of it's damage. -IV. Effects of application of calcium and phosphate materials on lead uptake by upland crops (농작물(農作物)에 대(對)한 납(Pb)의 흡수(吸收) 및 피해경감(被害輕減)에 관(關)한 연구(硏究) -IV. 밭작물(作物)의 납 흡수이행(吸收移行)과 석회(石灰) 및 인산(燐酸)의 영향(影響))

  • Kim, Bok-Young;Kim, Kyu-Sik;Han, Ki-Hak
    • Korean Journal of Soil Science and Fertilizer
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    • v.21 no.4
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    • pp.426-433
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    • 1988
  • A pot experiment was conducted to find out the effects of application of slacked lime and fused super-phosphate on the lead uptake of upland crops in a lead added soil. Lead concentration of the soils were adjusted to 0, 150, 300mg/kg respectively. The slacked lime was applied at the equivalent amount of lime requirement with extra 150kg/10a, and 2 times for the fused superphosphate. The results obtained were as follows: 1. Lead contents in crops increased in the order: sesame > maize > potato > sweet potato > soybean > green perilla > peanut > red bean. 2. Lead contents in parts of crops were increased in the order; root > stem > leaf > grain. 3. Increasing lead concentration in soils, lead content in the plant was increased and crops yield were decreased. 4. Lead contents in soybean and green perlilla were decreased in slacked lime application treatment. 5. The lead contents in leaf and grain of soybean and green perllila decreased with decreasing in the ratio of Pb/Ca+Mg equivalent in soil. 6. Grain yield were increased in slacked lime, but were decreased in fused superphosphate application treatment. 7. With increasing the soil Pb contents, calcium and phosphate contents were increased in leaf and stem, but calcium was decreased in roots. 8. $1N-NH_4$ OAC soluble Pb contents in soil were 26-50 ppm and 42-70 ppm, respectively, for 150mg/kg and 300mg/kg lead treatments. 9. The soil pH was increased in the order of slacked lime, fused superphosphate and nontreatment.

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Forage and TDN Yield of Several Winter Crops at Different Clipping Date (사료용 맥류 품종의 예취 시기별 청예 및 건물수량과 영양가 비교)

  • Hwang, Jong-Jin;Sung, Byung-Ryeol;Youn, Kyu-Bok;Ahn, Wan-Sik;Lee, Jong-Ho;Chung, Kyu-Yong;Kim, Young-Sang
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.30 no.3
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    • pp.301-309
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    • 1985
  • This experiment was conducted to know a substantial body of information about the differences of the important forage characteristics; green fodder yield, dry matter yield, TDN%, TDN yield and so forth of the seven cultivars selected as the forage crops (Rye, Triticale, Wheat and Barley) depending on the specific times of cutting stage, on the Wheat and Barley Research Institute from October, 1983 to June, 1984, and the results summarized as follows. Green fodder yield & dry matter weight, when clipped at 20, 30 April and 10 May, of varieties Homil #2 showed the most yielding capacity, but when clipped at 20 May, Suweon#8 (triticale) showed the most green fodder yield whereas Homil #1 the most significant dry matter weight. Plant height, in the cases of Paldanghomil, Homil #1 & Homil #2, showed distinctly longer than that of Bunong, Suweon #8 & Suweon #9 and continued to grow even after the heading date. Dry matter ratio increased with time (Dry matter yield/green fodder yield x100). TDN % decreased but TDN yield increased with time but Homil #1, Homil #2 and Paldanghomil showed relatively the higher values. In the elements of nutrient of cell wall, Suweon #8 & Bungong among 7 cultivars have good quality. The reasonable clipping date of wheat &barley as green fodder crops are 10 May to 20 May, but if clipped before 10 May and 20 May, Homil #2 and Suweon #8 became the promising forage crops, respectively.

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Effect of Green Manure Crop Cultivation on Soil Chemical Properties and Root Rot Disease in Continuous Cropping Field of Ginseng (녹비작물 재배가 토양화학성 및 인삼뿌리썩음병 발생에 미치는 영향)

  • Lee, Sung Woo;Park, Kyung Hoon;Lee, Seung Ho;Jang, In Bok;Jin, Mei Lan
    • Korean Journal of Medicinal Crop Science
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    • v.25 no.1
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    • pp.1-9
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    • 2017
  • Background: Some plants have harmful effects on fungi and bacteria as well as other plants. Incorporating such plant into soil as green manure is effective in reducing population densities of soil pathogens. Methods and Results: Twenty-three species of green manure crops were cultivated after the harvest of 6-year-old ginseng and then incorporated into the soil at the flowering stage. The following year, the root rot ratio of 2-year-old ginseng and soil chemical properties were investigated. In the absence of green manure addition, the $NO_3$ content, electric conductivity (EC), and K content decreased by 95%, 79% and 65%, respectively. In the presence of green manure addition, $P_2O_5$ and $NO_3$ contents reduced by 41% and 25%, respectively. The "survived root ratio" of 2-year-old ginseng significantly increased by 56.2%, 47.5%, and 47.3%, in the Sorghum sudanense, Ricinus communis and Helianthus tuberosus treatment, respectively. In addition, there was a significant increase in the "survived root ratio" in the Secale cereale, Chrysanthemum morifolium, Atractylodes macrocephala, and Smallanthus sonchifolius treatments. The "survived root ratio" of ginseng showed a significant positive correlation with the soil pH and a negative correlation with the $NO_3$ contents, and EC. Conclusions: Cultivation of plant form the Chrysanthemum family as green manure, using mainly the rhizomes was effective for the control of root rot disease of ginseng.

Strategies for the development of GM crops in accordance with the environmental risk assessment (I) (환경위해성 평가를 고려한 GM작물의 개발 전략 (I))

  • Lee, Shin-Woo
    • Journal of Plant Biotechnology
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    • v.38 no.2
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    • pp.125-129
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    • 2011
  • Environmental risk assessment (RA) is essential prior to the environmental release of GM crops. RA, however, costs at least 7 to 15 million US dollars and requires several years to complete field tests. Therefore, it is strongly suggested that developers of GM crops must consider all criteria for RA at the beginning stage of the development if it aims for commercialization. Previous review papers have pointed out that the "death valley" for the commercialization of GM crops is the screening stage of early GM events since many candidates are given up due to insufficient data on the molecular characterization of a GM event such as inserted gene's copy number, position of inserted site of a chromosome, flanking sequence of recombinant T-DNA, rearrangement of chromosome, and knock out of endogenous gene of host plant. Recently, Rural Development Administration (RDA) in South Korea has launched a Grand National Project named as "Next Generation of BioGreen 21 Project" from 2011 to 2020 and research funding for the development of global GM crops has been allocated to accelerate the commercialization of GM crops. In this regard, I strongly suggest that researchers involved in the development of GM crops for commercialization must conduct RA by themselves at the screening stage of pre-GM event based on the data for molecular characterization.