• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.167-173
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• 2002

This experiment was conducted to figure out the change of soil physical properties, rice growth and yield with the years of continuous cultivation in direct dry-seeding and no-tillage machine transplanting. Experiments were conducted at NHAES(National Honam Agricultural Experiment Station, RDA, Iksan, Cheon Buk Province, South Korea) with a rice variety "Dongjinbyeo" from 1995 to 2000. In no-tillage machine transplanting cultivation, organic matter in soil was higher than that on direct dry-seeding and was significantly high in topsoil. Problematic weed species were E. crus-galli B., A. keisak H., and L. japonica M. Plant height and tiller number m-2 were higher in common-tillage during the total growth duration. The highest weedy rice occurrence of 27.5% was observed in live years' continuous direct dry-seeding and followed by 6.2%, in four years', and 3.7%, in three years'. The highest yield reduction of 38% was observed in five years' continuous direct dry-seeding. The reduction may resulted from the competition between weedy rice and cultivated rice.

• Journal of Bio-Environment Control
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• v.14 no.1
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• pp.52-55
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• 2005

An experiment was conducted to evaluate the efficacy of continuous lateral shoot pinching and gradual adjustment of drip irrigation lines in improving plant health as well as fruit yield and quality in white-spined cucumber grown in the greenhouse. Grafted white-spined cucumber seedlings were established at a density of 18,000 plants per ha in a greenhouse. Main stems were pinched at 21st node. Each of the lateral shoots was pinched at the 3rd node and 2-3 fruits per lateral shoot were harvested. Drip irrigation lines were gradually adjusted to provide water to the area of maximum root concentration. Plants grown with these combined treatments produced $55\%$ more lateral shoots and 38% more marketable yield, as compared to the control.

• Korean Journal of Weed Science
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• v.13 no.2
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• pp.159-163
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• 1993

This research was conducted at the Crop Experiment Station to determine the changes of weed flora under direct seeded rice cultivation in dry paddy field from 1989 to 1992 and to establish an effective weed control strategy in direct seeded rice cultivation. With the continuous rice growing under direct seeded rice cultivation in dry paddy field, there were more occurrence in grasses and annual weeds while broadleaf and perennial weeds were diminished. The predominant weeds were aquatic weeds such as Eleocharis kuroguwai, Echinochloa crusgalli, and Monochoria vaginalis in machine transplanted rice paddy field while there were predominant of semi aquatic weed species such as E. crusgalli, Digitaria sanguinalis, Bidens tripartita, Aeschynomene indica, and Arthraxon hispidus in continuous direct seeded rice cultivation in dry paddy condition. Based on the vegetative analysis of weeds in terms of simpson index and community dominance, there was more distribution of weed species in direct seeded rice cultivation on dry paddy condition while only distributed with 1-2 weed species in machine transplanted rice paddy field. In similarity coefficient, there was a gradual increase up to 67% of weeds with the continuous direct seeded rice cultivation in dry paddy condition for 4 years starting from 41% of similarity coefficient.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.4
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• pp.255-264
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• 2001

This study was conducted to investigate changes in inorganic phosphorus fractions in phosphorus accumulated plastic film house soils under cropping condition. Pot experiment was conducted with surface soils taken from plastic film house fields cultivated for 3, 8 and 16 years. Phosphorus fertilizer was applied at the rates of 0 (P0), $100kg\;ha^{-1}$ (recommended application rate. P1) and $200kg\;ha^{-1}$ (P2) as fused phosphate. Crops were grown sequentially in the order of corn-Chinese cabbage-Chinese cabbage-corn for 3 years. The content of easily soluble-P fraction was decreased with cropping. There were significantly positive relationship not only between the contents of easily soluble-P and the amounts of soil available P ($r=0.839^{**}{\sim}0.952^{**}$ for Bray-1 P, $r=0.895^{**}{\sim}0.967^{**}$ for Lancaster P, and $r=0.491^{**}{\sim}0.821^{**}$ for Olsen P), but also between the amounts of P absorbed by plants and the amounts of easily soluble P decreased ($r=0.644^{**}{\sim}0.822^{**}$). The decrease of easily soluble-P during cropping period could be described by a first-order reaction. The number of cropping times needed to decrease the content of easily soluble-P to an index level of $0.2mg\;kg^{-1}$, which is commonly reported as the desired concentration for soil P, was predicted in the range of 26~33 cropping times by using the equations. Regardless of P fertilization, the proportion of Al-P to total P was little varied during cropping period, but the proportion of Fe-P to total P increased with cropping. Although the content of Ca-P was high before cropping, the proportion of Ca-P to total P was increased with cropping. The proportion of reductant soluble-P to total P was little varied for P fertilizer treatment but was increased for no P fertilizer treatment. The residual-P was decreased during cropping period due to the absorption by crops and the conversion to other inorganic P fractions.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2000.10a
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• pp.98-101
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• 2000

• Korean Journal of Weed Science
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• v.15 no.4
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• pp.305-312
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• 1995

Weed communities in the dry-direct seeded rice(Oryza sativa L.), soybean(Glycine max(L.) Merr.), and dry-direct seeded rice-soybean rotation system from the transplanted rice field were investigated in order to identify a change in weed species by paddy-upland rotation. Echinochloa species was the most dominant species in the dry-direct seeded rice and their great increase was observed in the continued practices of dry-direct seeded rice. Echinochloa spp., Chenopodium ficifolium, and Digitaria spp. were identified as the major weeds in soybean cultivation in paddy field. Practice of soybean rotation in the dry-seeded rice reduced weed occurrence, particularly at the soybean after 2-yr continued dry-direct seeded rice and at dry-direct seeded rice culture after 2-yr continued dry-direct seeded rice and at dry-direct seeded rice culture after 2-yr soybean compared to the continued cultures of rice or soybean. In addition, cultivation of dry-direct seeded rice or soybean culture in the paddy rice field seemed to be helpful for suppression of perennial weeds(Eleocharis kuroguwai, Cyperus serotinus, Scirpus juncoides) and aquatic weeds(Monochoria vaginalis, Sagittaria spp. Potamogeton distinctus).

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1997.11a
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• pp.34-35
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• 1997

무토양재배에서의 효율적인 관수량 결정은 정확한 증산량에 근거한다. 작물의 생육과 환경과의 관계 분석을 위해서 실제의 재배시스템 전체를 대상으로 하여 증산량을 연속적으로 측정하는 것은 현실적으로 어려우며, 가능하더라도 대규모의 시설이 필요하다. 따라서 작물의 실제 증산량을 위해서 개체 측정 등의 대표치를 이용하는 방법이 적용되고 있다. 본 연구에서는 일반적인 증산량 측정을 위해서 정량펌프를 이용한 측정 시스템의 구축 및 이 방법을 이용하여 관수량 제어를 위한 환경과 증산량과의 관계를 분석하였다. (중략)

• Journal of Bio-Environment Control
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• v.8 no.3
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• pp.172-182
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• 1999

Leaf lettuce(Lacaug sativa L.) was cultivated in deep flow culture to investigate growth and yield in relation to different reusing method of nutrient solution after once cultivation. Five different treatments were allocated to the nutrient solutions - Control(total renewal of solution), NSS(nutrient solution supplement), U control, NSAC(nutrient solution analysis and compensation), NSAC and Humus supply(NSAC with supply of Humus). The pH of solution was kept stable below 7.0 during 4 successive culture in NSAC and NSAC and Humus supply. U was sharply declined in NSS as the number of cultivation was increased. Gmwth and yield of NSAC was similar to those of Control because nutrient elements were kept the balance to the better growth, while the lettuce grown in NSS and EC control was shown lower growth rate. In the nutrient solutions, Content of N $O_3$-N and N $H_4$-N were remarkably decreased after the cultivation in all treatments. Ca and Mg were shown to be accumulated in nutrient solution regardless of culture times and treatments. After the first culture in NSAC and Humus supply, total N and P$_2$ $O_{5}$ content in leaves were lower than any other treatments, but Ca content was higher. Those were not significant as following cultures, and no significant difference of K and Mg content were shown among the treatments.

• Weed & Turfgrass Science
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• v.2 no.4
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• pp.348-351
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• 2013

Weedy rice is one of the major problems in direct-seeded rice field, resulting in poor rice quality and low grain yield. This study was carried out to evaluate the conversion effect to machine transplanting after wet-direct- seeding for 3 years on weedy rice occurrence, in comparison of repeated wet-direct-seeding. Occurrence of weedy rice in the continuous wet-hill-seeded and broadcasted field for 3 years increased 4 folds, when compared with that in machine transplanted rice paddy. In the first year of wet-direct-seeded field converted from machine transplanting, weedy rice occurrence did not increase, demonstrating lesser weedy rice in wet-hill-seeded than broadcasted field. These results indicate that alternate cultivation of wet-hill-seeding and machine transplanting is more effective to prevent weedy rice occurrence than the repeated wet-direct-seeding method for 3 years.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.285-285
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• 2009

벼 유기재배에 있어서 녹비작물을 이용하여 화학비료를 대신하고 있으나 녹비를 이용하기 위해서는 월동 전에 파종하고 이듬해 벼 이앙 전에 토양에 환원을 해야 하는 번거로움이 있다. 따라서 벼 재배 직전에 유기자재를 이용하여 화학비료를 대신하고자 했을 경우 유기자재를 전층시비와 표층시비의 차이에 따른 토양중의 이화학적 특성과 벼의 수량특성의 변화를 구명하였다. 벼 유기재배시 토양양분공급용으로 이용되고 있는 유기자재 4종을 공시하여 유기자재의 질소 성분량(7kg/10a)을 기준으로 하여 이앙 20일전에 시비방법별로 전층시비와 표층시비 2처리로 구분하여 전량 기비시비하고 경운한 다음 동진1호를 시험품종으로 하여 2년 연속 시비처리와 벼를 재배하면서 일어나는 토양의 이화학적 특성과 벼 생육 및 특성의 변화를 시기별로 조사하였다. 시험 전 토양의 화학성은 표층시비구의 염류농도, 가리와 석회의 함량이 다소 높아서 염류농도가 전층 시비구 보다 높은 조건의 토양이었다. 유기자재별 무기화 정도는 전층시비보다 표층시비를 할 때 약 20~30일 정도 빨랐다. 토양 중의유기물 잔존함량은 시비방법간의 큰 차이는 없었으나 표층시비를 할 경우 후기로 갈수록 다소 증가되는 경향이었으나, 전질소 잔존함량은 감소되었다. 토양 액상과 공극율은 전층시비>표층시비였으며, 입단 형성력도 같은 경향이었다. 토양 효소활성은 PME의 활성은 유기자재를 전층처리하였을 때 촉진되었으며, $\beta$-Glucosidase의 활성은 전층보다 표층처리시 활성이 높았다. 시비방법에 따른 벼의 수량 특성은 시비방법별로는 표층시비를 할 경우 전층시비보다 4~7%의 높은 특성을 보였으며, 관행대비 1년차에는 3~9%의 낮았으나, 2년 연속처리를 할 경우 대조구와 비슷해 지는 경향이었다.