• Journal of Biosystems Engineering
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• 제35권5호
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• pp.343-349
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• 2010

Rapid on-site sensing of nitrate-nitrogen and potassium ions in hydroponic solution would increase the efficiency of nutrient use for greenhouse crops cultivated in closed hydroponic systems while reducing the potential for environmental pollution in water and soil. Ion-selective electrodes (ISEs) are a promising approach because of their small size, rapid response, and the ability to directly measure the analyte. The capabilities of the ISEs for sensing nitrate and potassium in hydroponic solution can be affected by the presence of other ions such as calcium, magnesium, sulfate, sodium, and chloride in the solution itself. This study was conducted to investigate the applicability of two ISEs consisting of TDDA-NPOE and valinomycin-DOS PVC membranes for quantitative determinations of $NO_3$-N and K in hydroponic solution. Nine hydroponic solutions were prepared by diluting highly concentrated paprika hydroponic solution to provide a concentration range of 3 to 400 mg/L for $NO_3$-N and K. Two of the calibration curves relating membrane response and nutrient concentration provided coefficients of determination ($R^2$) > 0.98 and standard errors of calibration (SEC) of < 3.79 mV. The use of the direct potentiometry method, in conjunction with an one-point EMF compensation technique, was feasible for measuring $NO_3$-N and K in paprika hydroponic solution due to almost 1:1 relationships and high coefficients of determination ($R^2$ > 0.97) between the levels of $NO_3$-N and K obtained with the ion-selective electrodes and standard instruments. However, even though there were strong linear relationships ($R^2$ > 0.94) between the $NO_3$-N and K concentrations determined by the Gran's plot-based multiple standard addition method and by standard instruments, hydroponic $NO_3$-N concentrations measured with the ISEs, on average, were about 10% higher than those obtained with the automated analyzer whereas the K ISE predicted about 59% lower K than did the ICP spectrometer, probably due to no compensation for a difference between actual and expected concentrations of standard solutions directly prepared.

• 한국토양비료학회지
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• 제49권2호
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• pp.208-217
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• 2016

The Rural Development Administration moved to Jeonju for the balanced development of the land. This situation required establishment of new research fields with soils appropriate to cultivation. We applied a variety of amelioration techniques to mature soils of new research fields of the National Institute of Agricultural Science (NAS) and evaluated effects of the integrated amelioration techniques. The schedule of amelioration was following: 1) location of research fields was determined, 2) surface and subsoil samples were collected separately, 3) after aligning the top level of research fields, subsoil and surface soil were re-established with soil amendment, 4) the green manure crops were grown four seasons to improve the uniformity and increase the organic content of the research field, and 5) drainage canal and/or underdrainage were applied to poorly drained fields. The last green manure crop was rape in RDA fields and green barley in NAS fields. The average height, fresh weight, and dry matter weight of rape in good condition were 123 cm, $3,938kg\;10a^{-1}$, and $651kg\;10a^{-1}$, respectively. The height, fresh weight, and dry matter of green barley, on average, were 97 cm, $3,013kg\;10a^{-1}$, and $1,004kg\;10a^{-1}$, respectively. In the chemical properties of paddy field, pH and levels of silicate, calcium, magnesium, and potassium were in appropriate range but organic matter content of $16g\;kg^{-1}$ was less than the optimum level. In the chemical properties of upland field, pH and levels of phosphorus, calcium, magnesium, and potassium were appropriate range but organic matter content of $12g\;kg^{-1}$ was less than the optimum range. Evaluation of well-adapted soil was performed. The field in RDA was classified into the superior class with points ranging from 90 to 95 by the field evaluation test. The fields in NAS were mainly evaluated as the superior class with points greater than 85. However, some fields in NAS remained low quality with scores between 80 and 83. Further soil amelioration practices were suggested to fields with low soil quality.

• 한국토양비료학회지
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• 제42권4호
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• pp.257-265
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• 2009

토양미생물 군락에 대한 유기물 및 비료의 장기 연용 효과를 평가하고자 동일비료연용 논토양을 대상으로 미생물상, 미생물체량 및 세균 군락의 상호관계에 대해 조사하였다. 유기태 탄소함량은 비료를 연용한 곳 보다 볏짚 퇴비를 시용한 처리구에서 높았다. 토양 세균수는 무비구와 화학비료 시용구에 비해 퇴비, 석회, 규산을 병용한 처리구에서 비교적 높았다. 영년동일 논토양에서 Dactylosporangium, Ewingella, Geobacillus, Kocuria, Kurthia, Kytococcus, Lechevalieria, Micrococcus, Micromonospora, Paenibacillus, Pedobacter, Pseudomonas, Pseudoxanthomonas, Rhodococcus, Rothia, Sphingopyxis, Stenotrophomonas, Variovorax 등의 세균이 분리되었으며, Arthrobacter, Kocuria, Kurhtia 및 Bacillus 등의 세균이 우점하였다. 미생물체량 및 탈수소효소 활성은 볏짚퇴비 시용구에서 가장 높았다.

• 생물환경조절학회지
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• 제17권2호
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• pp.83-89
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• 2008

작물은 복잡한 형상 때문에 CFD모델에서 다공성 매체로 설계된다. 작물이 고려된 CFD 모델 해석을 위해서는 작물군락의 공기저항값을 입력하여야 하며, 이 값은 작물에 따라 달라진다. 본 연구에서는 풍동실험을 통해 국화군락의 공기저항 값을 구하였다. 풍상측에서는 풍속과 재식밀도가 증가할수록 정압이 증가하였다. 풍하측에서는 풍속이 증가할수록 정압이 낮아졌으나 재식밀도의 영향은 크게 받지 않는 것으로 나타났다. 풍속과 재식밀도가 증가할수록 풍상측과 풍하측의 압력차가 커지는 것으로 나타났다. 국화군락의 공기저항값인 항력계수 $C_d$값은 0.22였으며, Fluent 프로그램의 공기저항 계수로 이용한다. CFX 프로그램에서 필요로 하는 다공성 매체의 특성값 $K_Q$는 재식간격 $9{\times}9cm$일 때 2.22, $11{\times}11cm$일 때 1.81, $13{\times}13cm$일 때 1.07이었으며, 이 값을 CFX 프로그램의 quadratic resistance coefficient로 입력한다.

• 한국유기농업학회지
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• 제8권3호
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• pp.131-146
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• 2000

화학비료와 농약의 대용으로 가축분의 발효퇴비 및 미생물 발효퇴비를 시용하여 토양의 이화학적 성질 변화와 배추의 생육 및 체내 성분변화을 알아보기 위하여 본 시험을 수행하였던바 결과는 다음과 같다. 1. 유기농 자재를 시용한 토양의 화학적 성질을 보면 pH 및 유기물함량은 화학비료 처리구에서는 거의 변화가 없었던 반면 발효퇴비 및 미생물 발효퇴비 처리구에서는 약간 증가하였고, 인산, 칼슘 및 칼리 성분은 발효퇴비 및 미생물 발효퇴비 처리구에서 화학비료 처리구보다 증가하였으며, 특히 계분+미생물 발효퇴비 처리구에서 가장 높았다. 2. 유기농 자재를 시용한 토양의 미생물상의 변화는 화학비료 처리구에서는 세균 및 방선균수는 거의 일정한 경향을 보였고 사상균수는 약간 감소하는 경향을 보인 반면 발효퇴비 및 미생물 발효퇴비 처리구에서는 세균, 방선균 및 사상균수가 모두 증가하는 경향을 보였으며, 특히 미생물 발효퇴비 처리구에서는 세균수가 상당히 증가하였다. 3, 유기농 자재의 시용에 따른 배추의 생육은 화학비료 처리구> 미생물 발효퇴비 처리구> 발효퇴비 처리구순으로 높았고, 체내 NO$_3$$^{-}$ 함량은 내엽보다 외엽에서 많았고, 처리간에는 화학비료 처리구에서 내.외엽 모두 가장 많았으며, 미생물 발효퇴비 처리구에서 다소 적었다. 4. 유기농 자재의 시용에 따른 배추의 체내성분은 처리간 뚜렷한 차이는 나타나지 않았다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.308-308
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• 2017

The low and unstable yield of soybean has been a major problem in Japan. Excess soil moisture conditions are one of the major factors to restrict soybean productivity. More than 80 % of soybean crops are cultivated in converted paddy fields which often have poor drainage. In central and eastern regions of Japan, the early vegetative growth of soybean tends to be restricted by the flooding damage because the early growth period is overlapped with the rainy season. Field observation shows that induced excess water stress in early vegetative stage reduces dry matter production by decreasing intercepted radiation by leaf and radiation use efficiency (RUE) (Bajgain et al., 2015). Therefore, it is necessary to evaluate the responses of soybean growth for excess water conditions to assess these effects on soybean productions. In this study, we aim to modify the soybean crop model (Sinclair et al., 2003) by adding the components of the restriction of leaf area development and RUE for adaptable to excess water conditions. This model was consist of five components, phenological model, leaf area development model, dry matter production model, plant nitrogen model and soil water balance model. The model structures and parameters were estimated from the data obtained from the field experiment in Tsukuba. The excess water effects on the leaf area development were modeled with consideration of decrease of blanch emergence and individual leaf expansion as a function of temperature and ground water level from pot experiments. The nitrogen fixation and nitrogen absorption from soil were assumed to be inhibited by excess water stress and the RUE was assumed to be decreasing according to the decline of leaf nitrogen concentration. The results of the modified model were better agreement with the field observations of the induced excess water stress in paddy field. By coupling the crop model and the ground water level model, it may be possible to assess the impact of excess water conditions for soybean production quantitatively.

• 한국토양비료학회지
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• 제30권2호
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• pp.146-151
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• 1997

주요(主要) 채소류(菜蔬類) 재배지 토양의 화학적 특성을 밝히고, 화학성분 함량의 변동양상(變動樣相)을 파악하여 토양개량(土壤改良) 및 시비량(施肥量) 기준설정(基準設定)의 기초자료(基礎資料)로 활용(活用)하고자 고추, 마늘, 양파, 수박, 무, 배추, 감자 등의 주산단지(主産團地)에서 작물별로 30개 포장(圃場)(합계(合計) 210개 포장(圃場))을 선정(選定)하여 토양화학성을 조사(調査)한 결과(結果)는 다음과 같다. 1. 노지채소(露地菜蔬) 재배지 토양의 양분함량은 대체적(大體的)으로 채소류 재배에 적합(適合)하나 성분별(成分別)로 구분(區分)하여 보면 pH와 유기물(有機物), 고토(苦土)등은 밭토양 개량목표에 미달(未達)되고 있으나 인산과 가리는 개량목표를 상회(上廻)하였다. 2. 채소류 재배지 토양의 양분함량(養分含量)을 작물별로 구분(區分)하여 보면 마늘>감자>배추>양파>고추>무>수박 재배지 순(順)으로 높았다. 3. 채소류 재배지 토양의 미량원소(微量元素) 함량(含量)은 Fe 71~89, Mn 38~40, Cu 1.4~1.6, Zn 2.2~3.0 mg/kg 범위(範圍) 이었다. 4. 밭토양의 화학성분 분포비율(分布比率)을 보면 pH는 5.0 이하가 41%인 반면(反面) 유효인산과 치환성 칼리 및 석회는 각각(各各) 73, 47, 63%가 밭토양 개량목표(改良目標)를 상회(上廻)하고 있다.

• 한국산학기술학회논문지
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• 제21권4호
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• pp.471-478
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• 2020

본 연구는 농업R&D 평가의 중요한 요소인 생산성, 시장성, 지역파급성을 기초로 우수한 농업 R&D의 특성을 분석하여 향후 농업R&D 개발방향의 시사점을 마련하기 위한 목적으로 수행되었다. 분석대상은 2006년부터 2018년까지 국가연구개발우수성과에 선정된 농촌진흥청의 R&D이며, 우선순위는 계층분석방법을 활용하여 분석하였다. 주요 분석결과는 다음과 같다. 먼저, 상위 평가기준의 중요도는 시장성(0.423) > 지역파급성(0.360) > 생산성(0.216)의 순서로 나타났다. 둘째, 하위 평가기준의 중요도를 분석한 결과, 시장성의 경우 사업화 가능성(0.515)이, 지역파급성의 경우 보급확대 가능성(0.538)이, 생산성의 경우 품질향상(0.464)이 높은 것으로 나타났다. 셋째, 중요도가 상대적으로 높게 나타난 우수성과는 원예작물의 농업경쟁력 향상과 관련된 기술이 다수 포함되었다. 특히, 원예작물의 품종개발 및 수출, 환경변화에 취약한 원예작물의 병해충 진단 및 친환경 농약 개발, 벌의 대량 생산 및 실용화를 통한 원예작물과의 시너지 효과 창출 등과 관련된 R&D의 순위가 높게나타났다. 농업R&D는 농업기술혁신을 통해 국민의 삶의 질 향상을 견인해 왔다. 다만, 농업환경이 빠르게 변화되고, 다양한 스마트기술이 농업현장에 접목되고 있는 상황에서 생산성의 향상 보다는 시장성이 요구되고 있다. 또한, '지역특화작목 연구개발 및 육성에 관한 법률'의 제정과 함께 지역의 특성에 적합하고, 비교우위 가진 기술의 지역적 보급확대가 요구되고 있다. 본 연구가 농촌진흥기관이 지역특화작목을 육성하고, 경쟁력을 향상하는 과정에서 요구되는 농업R&D의 개발방향을 결정하는 데 도움이 되길 기대한다.

• The Plant Pathology Journal
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• 제19권2호
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• pp.117-122
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• 2003

Six isolates of Turnip mosaic Potyvirus (TuMV) namely, TuMV-CA7 from oriental cabbage, TuMV-TU and TuMV-TU2 from turnip, TuMV-RA from rape, TUMV-ST from stock, and TuMV-R9 from radish, and Ribgrass mosaic Tobamovirus (RMV-FG22) from oriental cabbage were isolated. Three kinds of characteristics of the six TuMV isolates were sorted by bioassay: TuMV-CA7 and TuMV-TU isolates infected mostly oriental cabbages; TuMV-ST, TuMV-TU2, and TuMV-R9 infected radishes; and TuMV-RA infected both oriental cabbages and radishes. Mixed infections of crucifers were RMV-FG22+TuMV-CA7, RMV-FG22+TuMV-TU, RMV-FG22+TuMV-RA, RMV-FG22+TuMV-ST, RMV-FG22 +TuMV-TU2 and RMV-FG22+TuMV-R9. Crops used were 'Tambok' cultivar resistant to TuMV, 'SSD63' susceptible inbred line of oriental cabbage, pure line of leaf mustard and 'Daeburyungyeorum' cultivar of radish. New specific ultrastructures of nonagon-like ring (NLR) and spiral aggregates (SA) by mixed infection with TuMV and RMV were formed in cells of crucifer plants. The NLR was made by a TuMV surrounded loosely by nine RMV particles, and the SA was formed spirally by full mixed of two virus particles. The SA had some NLR in its center, which was observed from cross sectioned SA. Host plants with specific ultrastructures expressed synergistic symptoms. Specific ultrastructures of NLR and SA were formed in combinations of RMV-FG22 and in TuMV-CA7, TuMV-TU, or TuMV-RA that could infect oriental cabbages. How-ever, no specific ultrastructures and mixing of the two virions in the same cell were observed in combinations of RMV-FG22, and TuMV-57, TuMV-TU2, or TuMV-R9 isolates haying virulence in radishes.

• 한국잡초학회지
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• 제1권1호
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• pp.5-14
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• 1981

Weed is one of the problems in the crop land as well as in uncultivated land, raising the farm management costs. Therefore, the weed control is essential for effective agricultural management. The cost for weed control in Korea occupies on the average 27.6% of the total labor cost required. Agricultural policies since 1960 were transferring from yield increase due to land productivities to increase of income due to labor productivities. Therefore, the weed control by hand is also changed to weed control by chemicals. The weed control by chemicals has also brought about some side-effects and needs better, improved weed control methods. The present weed control situation and related problems were studied to present new approaches for agricultural development in the future. There were 458 species of weeds in 82 families which were growing in the crop land. The weeds to control, however, are 12 in paddy field and 9 in upland. So far weeds in paddy field are well under control, while weeds in upland are poorly controlled due to change in chemical efficiency and chemical damage in the upland. The administration, research and extension work for the efficient use of agricultural chemicals have been done by various institutions, such as Office of Rural Development, Office of Forestry, and chemical companies. The courses for agricultural chemicals were offered in the agricultural colleges. However, the efficiency of chemicals could not be maximized due to the poor relationships among related institutes. The newly established Agricultural Chemical Research Center at the Office of Rural Development and the Korean Weed Science Association are expected to contribute toward improving weed control in Korea. The Korean agriculture in the future will eventually be mechanized and the varieties resistant to high nitrogen application and to high plant density will be required for high yields. The rice will be transplanted earlier and the whole growing period will be extended. The application of organic matter will be increased for increasing soil fertility, and the use of agricultural chemicals will be continued. Under such a condition, the studies on the weed occurrence and its integrated control measures will be needed. Also weed controls in the newly exclaimed land, crop varieties, horticultural varieties, forage crops, and forests are also needed to study. Basic and practical researches for the weed control to improve the labor productivity will be also needed. In order to meet the all requirements for efficient weed control, weed control systems including all the academics, research and extension workers, administratives, farmers and companies should be established. Also securing researchers and education of personnels are pre-required and research funds for the chemical studies should be provided efficiently and timely.