• Journal of Ecology and Environment
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• 제33권4호
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• pp.317-323
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• 2010

Nutrient availability is a critical component of agroecosystems, and is relevant to both above- and below- ground interactions. The principal objective of this study was to determine how the cessation of fertilization affects the communities of weeds and soil organisms in a corn/wheat field. Changes in dominant weed species, substrate-induced respiration, and the population density of nematodes and microarthropods were evaluated. Microbial substrate-induced respiration (SIR) and the population density of microarthropods decreased following the cessation of fertilization and were partly correlated with the aboveground weed biomass. The cessation of organic fertilizer application but continuing application of inorganic fertilizer reduced the population density of nematodes. In response to the cessation of fertilization, weed communities were dominated by species with little dependency on fertilization. Amaranthus retroflexus was identified as the most dominant species in the corn field; however, it was replaced by Digitaria ciliaris after the cessation of fertilization. In the wheat field, the cessation of fertilization led to a rapid reduction in the biomass of most weeds, except for Vicia angustifolia, supposedly as the result of symbiotic nitrogen fixation. Additionally, the fact that weed biomass was partially correlated with SIR or the population density of microarthropods may reflect a mutual feedback between soil organisms and weeds. The results indicate that the cessation of fertilization alters communities of weeds and soil organisms through changes in weed biomass and interactions with symbiotic microorganisms.

• 한국유기농업학회지
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• 제20권2호
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• pp.201-209
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• 2012

본 시험은 유기농업 파 및 고추재배를 위하여 호밀과 헤어리베치를 겨울에 윤작하여 잡초 발생량 억제에 미치는 효과를 검토하기 위하여 수행되었다. 파 재배구에서 호밀을 토양에 환원하지 않은 처리구에 비해 호밀을 환원하였을 경우 잡초발생량을 52% 경감시켰다. 고추 재배구에서는 그러한 효과가 뚜렷하게 관찰되지 않았다. 파 재배시 어저귀, 참방동사니, 바랭이와 같은 초종은 호밀뿌리 분비물에 의해 발아가 억제되는 경향이었으나 헤어리베치는 그러한 발생억제 효과가 크지 않았다. 파 재배시 호밀 환원은 잡초발생량을 경감시켰고 잡초의 종 다양성 지수를 증가시켰다.

• 한국잡초학회지
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• 제4권2호
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• pp.135-142
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• 1984

간척지(干拓地)의 개답년차(開沓年次) 진전(進展)에 따른 합리적(合理的) 잡초방제안(雜草防除案)을 구명(究明)하기 위한 기초자료(基礎資料)를 얻을 목적(目的)으로 계화도간척지(界火島干拓地) 지표분석(指標分析)을 하였다. 결과(結果)는 다음과 같이 요약(要約)할 수 있었다. 1. 조사지(調査地)의 토양염분온도(土壤鹽分濃度)는 대부분(大部分) 0.2% 이하(以下)로, pH는 5.5~6.5의 범위(範圍)로 변동(變動)되어 있었다. 2. 조사지(調査地)의 발생초종(發生草種)은 17종(種)으로서 매자기가 우점(優占)하고 있었으나 숙답화(熟畓化)와 함께 물달개비 쇠털골 알방동산이 등의 출현(出現)이 증가(增加)하는 경향(傾向)이었다. 3. 염온도(鹽溫度)가 낮아지고 pH가 5.5~6.5 범위(範圍)로 가까워질수록 발생초종수(發生草種數), 발생본수(發生本數), Biomass, 종다양도(種多樣度), 균재도(均在度), Sociability index가 커지는 반면에 군락특이도(群落特異度)는 작아지는 경향(傾向)이 있다. 4. 숙답화(熟沓化)가 진전(進展)될수록 온도잡초(溫度雜草), 다년생사초과(多年生莎草科), 근경횡주형(根 莖橫走型)의 잡초종(雜草種)이 줄고 일년생광엽잡초(一年生廣葉雜草)로서 풍수전파형(風水傳播型) 단립형(單立型)의 잡초종(雜草種)이 늘어가는 경향(傾向)이었다. 5. 숙답화(熟畓化)에 따른 잡초종(雜草種)의 천이(遷移) 다양화(多樣化) 다량화(多量化)가 예상되며 이에 대한 식생수준(植生水準) 및 유입전파(流入傳播)의 예방 대책이 요구(要求)될 것으로 판단(判斷)되었다.

• Journal of Ecology and Environment
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• 제36권3호
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• pp.167-172
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• 2013

A Two-year field experiment was carried out in 2009 and 2010 to evaluate the effects of different densities of wild oat and nitrogen (N) rates on oilseed rape yield and yield components. Experimental design was split plot with three replications. Increased nitrogen rates up to 150 kg N/ha caused an increase in oilseed rape grain yield in weed-free plots (4.26 t/ha; 1t = $10^3kg$), while even at the lowest density of wild oat (15 $plants/m^2$), increasing N fertilizer only up to 50 kg/ha led to a significant increase in grain yield. Wild oat growth was favored by high levels of N. Intraspecific competition reduced biomass, 100-seed weight and number of tillers of wild oat. Both lower N rate and intraspecific competition had negative effect on wild oat growth but the weed was still able to produce a considerable number of tillers and vigorous seeds. It showed that wild oat possess a notable adaptive plasticity and can allocate a greater proportion of its resource toward reproductive organs even under resource shortage conditions and, thus, it may increase the competitive ability of the weed over the crop.Our results suggest that effective weed management should be done to prevent wild oat seed production in crops preceding oilseed rape as well as to control the weed at early season in oilseed rape fields.

• Korean Journal of Chemical Engineering
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• 제35권12호
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• pp.2413-2420
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• 2018

Sida acuta, a common type of weed in Thailand, contains relatively high cellulose (42.7%) content. We pretreated NaOH to improve glucose recovery from S. acuta. The effect of pretreatment temperature and NaOH concentration was fundamentally investigated based on hydrolysis efficiency with recovery of solid fraction. The pretreatment condition was determined to be 3% NaOH at $60^{\circ}C$ for 9 h, which showed the highest glucose recovery. The hydrolysates obtained by enzymatic hydrolysis of S. acuta were applied to the fermentation of Saccharomyces cerevisiae K35, and a theoretical yield of 97.6% was achieved at 18 h. This indicated that the hydrolysates medium without detoxification had no negative effects on the fermentation. The production of biomass into bioethanol was evaluated based on the material balance of 1,000 g basis. Following this estimation, approximately 28 g and 110 g bioethanol could be produced by untreated and pretreated S. acuta, respectively, and this production was improved about 3.9-fold by NaOH pretreatment. These results again show the importance of pretreatment in biorefinery process.

• 한국잡초학회지
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• 제32권1호
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• pp.17-24
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• 2012

The study was conducted to investigate the effect of weed interference and starter fertilizer on subsequent soybean seed quality at the Agricultural Research Farm and Laboratory of Razi University, Kermanshah, Iran. Two factorial experiment was laid-outon a randomized complete block design with four replications. First factor was starter fertilizer levels (0 and 25 kg $ha^{-1}$) applied in the forms of monoammonium phosphate, the second factor was different weed interference periods consisted of five initial weed-free periods (in which, plots were kept free of weeds for 0, 15, 30, 45 and 60 days after crop emergence (DAE) and then weeds were allowed to grow until harvest) and five initial weed-infested periods (in which, weeds were allowed to grow for 0, 15, 30, 45 and 60DAE, after which the plots were kept free of weeds until harvest). Full season weedy condition reduced 100-seed weight, seed germination percentage and seedling dry weight by 25.9, 13.3 and 22.5%, respectively and increased mean germination time and seed electrical conductivity by 55.8 and 24.3%, respectively as compared with full season weed-free control. However, the traits under study were not significantly influenced when field was kept free of weeds for at least 45 DAE (R1) or weedy condition was continued for less than 30 DAE (V8). There was a significant and negative correlation between weed biomass and seed weight (r = -0.93), so that when weed free condition was less than 45 DAE or weed infested period was continued for at least 30 DAE, soybean plants produced wrinkled and underdeveloped seeds with lower weights and qualities. Moreover, soybean seed quality reduction due to weed interference was more evident when starter fertilizer was applied and weeds interfered with soybean from the beginning of the growing season. Information from the present study is beneficial in soybean seed production systems and where farmers use the harvested seeds for the following planting.

• Weed & Turfgrass Science
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• 제3권4호
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• pp.318-322
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• 2014

본 연구는 유기농업을 위한 중경제초기 개발로 제초날 형상 등 제초기 본체와 헤어리베치 파종시기 및 경운방법별 잡초발생 양상과 수량을 분석하였다. 헤어리베치의 건물량은 추파가 $6,730g\;ha^{-1}$로 춘파 $1,690g\;ha^{-1}$보다 3배 이상 높았다. 파종시기에 따른 헤어리베치의 식물체 분석을 보면, 전 질소는 추파가 5.4 kg으로 춘파 2.0 kg에 비해 2배 이상 높았다. 관행 비닐멀칭구에 비해 헤어리베치 처리구가 초장, 경태, 그리고 엽수가 다소 작았고, 출수기도 추파구는 8일, 춘파구는 12일 지연되었다. 잡초방제가는 무피복 대비 각각 피복비닐구, 부분경운구가 각각 88%, 71% 순이었다. 수량은 단작 비닐멀칭구가 $2,310kg\;ha^{-1}$, 추파 부분 경운구가 $2,130kg\;ha^{-1}$이었다.

• 한국토양비료학회지
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• 제44권4호
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• pp.581-590
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• 2011

Organic farming is rapidly expanding worldwide. Crop growth in organic systems greatly depends on the functions performed by soil microbes, and nutrient supply weed suppression by green manure crops input. Four red-pepper production systems were compared: 1) bare ground (conventional system); 2) hairy vetch monoculture; 3) rye monoculture; and 4) hairy vetch-rye mixture. Soil inorganic N reached the peak at 30 DAI and hairy vetch monoculture was the highest ($192mg\;kg^{-1}$) and soil total carbon was fluctuated sporadically during the experiment. Carbohydrate and phenolic compounds in soil kept significantly higher in green manure crops systems from 10 DBI to 30 DAI, however the level was the maximum at 10 DBI (carbohydrate) and 30 DAI (phenolic comounds). Incorporation of green manure crops residue enhanced soil microbial biomass C and N throughout the growing season except that MBN in rye was reduced after incorporation. Green manure crops systems suppressed weed occurrence and, in particular, it was prominent in rye monoculture. Mineral elements composition and production in red-pepper fruits were markedly decreased in green manure crops systems although hairy vetch monoculture has come close to bare ground (NPK-applied). Therefore, it was suggested that higher biomass production should be performed not only to improve soil quality and suppress weeds but to yield suitable red-pepper fruits in green manure crops-based organic farming.

• 한국잡초학회지
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• 제15권4호
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• pp.313-320
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• 1995

논을 밭으로 전환(轉換)하여 콩을 파종 재배하였을 때 잡초발생동태 및 효과적인 방제체계를 확립하기 위하여 수행한 일련의 시험결과를 요약하면 다음과 같다. 1. 밭으로 전환시(轉換時) 주요 발생 잡초는 (좀)바랭이, 피, 좀명아주, 속속이풀, 벼룩나물 등이었으며 첫해보다는 2년째에 광엽잡초 특히, 좀명아주, 속속이풀의 발생량이 크게 증가하였으며, 4월 26일 파종구에 비하여 5월 20일에 파종했을 때 잡초의 발생량이 84.8%(건물중 기준) 감소되었다. 2. 무방제(無除草) 방임(放任) 상태(狀態)에서는 콩의 분지수, 주경의 지름, 꼬투리수에 크게 영향을 미치고, 콩의 수량이 70% 감소되었다. 3. 답전윤환 콩재배지에서는 pendimethalin, metolachlor, metolachlor+prometryn, alachlor 처리로 효과적인 잡초방제가 가능하였고 그 중에 metolachlor+prometryn가 가장 우수하였다.

• 한국작물학회지
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• 제56권3호
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• pp.192-198
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• 2011

생육 중인 호밀 리빙멀치 사이 부분경운 기계화 콩 파종기술체계를 가지고 2007년은 호밀의 파종시기를, 2009년은 시험장소를 달리하면서 잡초억제 및 콩의 생육 및 수량에 미치는 영향을 조사하였는데, 중요한 사항을 요약하면 다음과 같다. 1. 4월초~5월초에 파종한 호밀 리빙멀치에 의한 콩 파종 후 40~50일까지의 잡초억제 효과는 70~90%로 현저히 높았는데, 호밀 파종기에 따른 잡초억제의 차이는 없었다. 또 호밀 리빙멀치의 잡초억제 효과는 콩 수확기 까지 지속되었다. 2. 잡초 초종별로는 잡초발생량의 60~80%를 차지하는 피에 대한 리빙멀치의 잡초억제 효과가 뛰어났으며 일찍 발아한 명아주보다 콩 파종 후 발아한 피, 바랭이 및 쇠비름에 대한 억제효과가 높았다. 3. 호밀을 4월 초에 파종한 것이 4월 말~5월 초에 파종한 것보다 콩 파종 시 리빙멀치량이 많았으며, 그에 따라 콩 초기생육이 많이 억제되었고, 수확기 종실수량의 감소에도 영향을 주는 것으로 나타났다. 4. 호밀을 4월 말~5월 초에 파종했을 때 콩의 초기생육은 억제되었지만 호밀이 고사한 후에 콩의 생육이 많이 회복되었고, 종실수량은 관행재배와 차이를 나타내지 않았다. 2008년 지역별 시험에서는 콩 종실수량은 호밀 리빙멀치 유무보다 지역의 포장조건에 따른 영향이 컸다. 5. 봄 잡초발생 경향, 리빙멀치량에 따른 잡초억제, 콩 초기생육 및 종실수량에 미치는 영향을 고려할 때 호밀 리빙멀치 사이 부분경운 기계화 콩 파종체계에서 호밀의 파종시기를 4월말 이전으로 당기는 것은 바람직하지 않았다.