• 한국환경과학회지
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• 제25권8호
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• pp.1143-1153
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• 2016

Plant biomass, photosystem II (PSII) photochemical activity, photosynthetic function, and zinc (Zn) accumulation were investigated in a sorghum-sudangrass hybrid (Sorghum bicolor ${\times}$ S. sudanense) exposed to various Zn concentrations to determine the elimination capacity of Zn from soils. Plant growth and biomass of the sorghum-sudangrass hybrid decreased with increasing Zn concentration. Symptoms of Zn toxicity, i.e., withering and discoloration of old leaves, were found at Zn concentrations over 800 ppm. PSII photochemical activity, as indicated by the values of $F_v/F_m$ and $F_v/F_o$, decreased significantly three days after exposure to Zn concentrations of 800 ppm or more. Photosynthetic $CO_2$ fixation rate (A) was high between Zn concentrations of 100-200 ppm ($22.5{\mu}mol$ $CO_2{\cdot}m^{-2}{\cdot}s^{-1}$), but it declined as Zn concentration increased. At Zn concentrations of 800 and 1600 ppm, A was 14.1 and $1.8{\mu}mol$ $CO_2{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. The patterns of stomatal conductance ($g_s$), transpiration rate (E), and water use efficiency (WUE) were all similar to that of photosynthetic $CO_2$ fixation rate, except for dark respiration ($R_d$), which showed an opposite pattern. Zn was accumulated in both above- and below-ground parts of plants, but was more in the below-ground parts. Magnesium (Mg) and iron (Fe) concentrations were significantly low in the leaves of plants, and symptoms of Mg or Fe deficiency, such as a decrease in the SPAD value, were found when plants were treated with Zn concentrations above 800 ppm. These results suggest that the sorghum-sudangrass hybrid is able to accumulate Zn to high level in plant body and eliminate it with its rapid growth and high biomass yield.

• 한국토양비료학회지
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• 제44권1호
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• pp.91-97
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• 2011

The objectives of this research were to investigate the system of rice intensification (SRI) on early growth, grain yield, and yield components under Chinese milk vetch residue-mulched no-tillage cropping systems at silt loam soil. The field was prepared as a split-plot design with three replications, main plots consisted of Dongjinbyeo, and Sobibyeo as a cultivar, and subplots consisted of $10{\times}10$ cm, $20{\times}20$ cm, and $30{\times}30$ cm as a planting density. Weed infestation during rice growing season was more severe in wider planting density $30{\times}30$ at 35 days after transplanting (DAT), and $20{\times}20$ cm at 95 DAT in both Sobibyeo and Dongjinbyeo. The maximum plant height was recorded in Sobibyeo compared with Dongjinbyeo, $10{\times}10$ cm and $20{\times}20$ cm planting density compared with $30{\times}30$ cm from 20 DAT until 60 DAT. Among the three planting densities, SPAD values were significantly greater in planting density of $20{\times}20$ cm both in Sobibyeo and Dongjinbyeo followed by $30{\times}30$ cm compared with closer planting density of $10{\times}10$ cm. The lowest grain yield was observed in wider planting density of $30{\times}30$ in both Sobibyeo and Dongjinbyeo due to lower number of panicle per unit area. Our findings suggest that optimum planting density for SRI in no-tillage paddy was $20{\times}20$ cm and it should be useful the systems to small-scale rice farmers in Korea as a sustainable farming system.

• 한국초지조사료학회지
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• 제21권2호
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• pp.53-58
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• 2001

Jeju Italian millet was grown at five planting densities(5$\times$5, 15$\times$15, 20$\times$20, 25cm) form May 13 to Aug. 14, 2000 at jeju island to determine influence of planting density on agronomic characters, forage yield and quality. Days to heading increased from 87 to 89 days as planting density was decreased. In 5$\times$5cm planting density plot, plant height was 185.4cm and it was gradually decreased as planting density was increased. So in 30$\times$30cm planting density plot, plant height was 173cm. As planting density increased, stem diameter, the number of nodes per plant, the umber of leaves, leaf width and SPAD reading values was increased, the longer leaf length as the broader planting density. Fresh forage yield increased from 29.99 to 55.01MT/ha, dry matter(DM) yield from 8.04 to 15.59MT/ha, crude protein(CP) yield from 0.78 to 2.26MT/ha and total digestible nutrients(TDN) yield from 3.65 to 7.93MT/ha as planting density was decreased. Crude protein content increased from 9.8 to 14.5% ether extract comtent from 1.4 to 1.9%, nitrogen free extract content from 38.4% to 38.9% and TDN content from 45.4 to 50.9%, but crude fiber content decreased from 34.5 to 30.1% and crude ash content from 9.1 to 8.0% as planting density was decreased.

• 농업과학연구
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• 제49권3호
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• pp.561-570
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• 2022

This study investigated the changes in planting environment and growing conditions of 'Arisoo' apple trees under shading net treatments. Apple tree canopies were fully covered with Blue (blue color net, mesh size: 4 mm × 5 mm), Black-A (black color net, mesh size: 4 mm × 5 mm), Black-B (black color net, mesh size: 5 mm × 6 mm), and uncovered trees were used as the control. Inside the tree canopies, the illuminance was observed as 100% (85.0 Klux) in the control, but it decreased to 75% (64.3 Klux) in the Blue, 73% (63.0 Klux) in the Black-A, and 77% (65.9 Klux) in the Black-B nets, respectively. The solar irradiance was observed as 755 w·m^-3 in the control, but it was decreased to 715 w·m^-3 in the Blue, 624 w·m^-3 in the Black-A, and 647 w·m^-3 in the Black-B nets, respectively. The average daily temperature was observed to be the highest in the Black-A net (31.8℃) while it was observed to be around 30.0℃ in the control, Blue, and Black-B nets. In addition, the average fruit surface temperature was observed to be the highest (39.4℃) in the control, but it was decreased to 38.1℃ in the Blue, 37.3℃ in the Black-A, and 39.0℃ in the Black-B nets. However, the average soil temperature, the shoot growth rate, and leaf SPAD values were not different in all the treatments. Fruit sunburn disorders were the highest in the control while it was observed to be lower in the fruits from trees covered with the shading nets. However, at harvest, the fruit quality parameters were not different in all the treatments. Overall, this study suggests that the apple trees covered with the shading nets reduced the illuminance, solar irradiance, fruit surface temperature, and fruit sunburn disorders. However, the shading nets did not affect tree growth and apple fruit quality.

• 농업과학연구
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• 제49권3호
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• pp.643-653
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• 2022

This study investigated which nutrient solution is suitable for growth and secondary metabolite contents when three different vegetable plants are grown simultaneously in one hydroponic cultivation bed. Seeds of pak choi (Brassica compestris L. ssp chinsensis), red mustard (Brassica juncea L.), and arugula (Eruca sativa Mill.) were sown in the shape of a triangle in three places on rockwool cubes. The rockwool cubes were placed in semi deepflow technique (semi-DFT) hydroponic systems in a rooftop greenhouse after three weeks of growth as seedlings then cultivated with four different nutrient solutions, Korea Horticultural Experiment Station (KHE), Hoagland, Otsuka-A, and Yamazaki, at the rooftop greenhouse for two weeks. The leaf area of pak choi cultivated in Otsuka-A was the largest but SPAD values, leaf area, and fresh weight of arugula were highest with KHE treatment. The total glucosinolate (GSL) content of pak choi was 151.7% higher in KHE than in Hoagland, and there was no significant difference in Yamazaki and Otsuka-A treatments. The total GSL content of red mustard was 34.6 μmol·g^-1 in Hoagland, and it was 32.6% higher in Hoagland than in Yamazaki. Total GSL content of arugula was 57.5% higher in Yamazaki and Hoagland nutrients than in KHE and Otsuka-A nutrients solutions. The total GSL content of three plants grown with KHE was 40.7% higher than with Yamazaki, and the other nutrient solutions did not show significant differences. Therefore, KHE nutrient solution is considered suitable for nutrient solution composition for the cultivation of three different Brassicaceae crops in a single hydroponic cultivation system.

• Journal of Plant Biotechnology
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• 제50권
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• pp.183-189
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• 2023

This study investigated the impact of two distinct MS basal media: one containing FeNaEDTA and the other FeEDDHA, on the growth of five unique gerbera cultivars (Shy Pink, Pink Holic, Breeze, Harmony, Snow Dream). Notably, the response to these media types varied significantly among the cultivars, particularly concerning leaf yellowing and plant growth. 'Shiny Pink' and 'Pink Holic' exhibited leaf yellowing on the FeNaEDTA-containing medium but displayed leaf greening on the FeEDDHA-containing medium. In contrast, 'Snow Dream,' 'Harmony,' and 'Breeze' remained unaffected on both medium types. However, the FeNaEDTA-containing medium promoted higher plant height and petiole length in 'Breeze,' 'Harmony,' and 'Snow Dream' than the FeNaEDTA-containing medium did. A promotive effect of silver nanoparticles (AgNPs) on plant growth and leaf greening was observed in 'Pink Holic,' particularly on the FeNaEDTA-containing medium, while the addition of AgNPs to the FeEDDHA-containing medium negatively affected plant growth. These results highlight the substantial influence of medium type, specifically the presence of FeNaEDTA or FeEDDHA, on gerbera growth responses, emphasizing the critical role of medium selection in gerbera propagation. Additionally, when contemplating the addition of AgNPs for in vitro gerbera propagation, it is crucial to consider the medium type.

• 한국작물학회지
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• 제65권4호
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• pp.468-476
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• 2020

본 연구는 씨감자 생산에 적합한 분무경재배용 경삽묘를 폐쇄형식물생산시스템을 이용하여 생산하기 위한 광도조건을 설정하기 위하여 수행하였다. 감자(Solanum tuberosum L.) '수미'와 '추백'의 경정배양묘를 순화한 다음 삽수를 채취하여 경삽하였다. 서로 다른 LED 광도(60, 120, 180, 그리고 240 μmol·m^-2·s^-1)에서 40일간 육묘하고, 80일간 분무경재배하였다. 1. LED 광도 60 μmol·m^-2·s^-1에서 경삽묘를 육묘하였을 경우 '수미' 17.3 cm, '추백' 16.1 cm로 두 품종 모두 초장이 가장 길었고, 마디수도 많았다. 광도가 높을수록 초장은 작고 마디수도 적었다. 2. 품종에 따라 엽면적이나 SPAD 값, Fv/Fm 값은 육묘기의 광도에 따라 약간의 차이를 보였다. 경삽묘의 생체중은 60 μmol·m^-2·s^-1 광도에서 가장 무거웠으며, 건전묘 생산율도 두 품종 모두 60 μmol·m^-2·s^-1 광도에서 가장 높았다. 3. 분무경재배에서 LED 광도 60 μmol·m^-2·s^-1에서 육묘한 경삽묘가 품종간 차이를 보이기는 하지만 지상부 경엽중이 가장 무거웠고, 정식판 아래 경삽묘장이 가장 길고 뿌리 무게도 가장 무거웠으며, 광도가 높을수록 가벼웠다. 4. 복지수에 있어서도 품종간 차이는 있으나 60 μmol·m^-2·s^-1 광도에서 육묘한 경우 '수미' 4.2개/주, '추백' 7.7개/주로 가장 많았다. 또한 60 μmol·m^-2·s^-1 광도에서 괴경수 및 총괴경중이 가장 좋았는데 광도가 높을수록 두 품종의 총괴경수와 총괴경중이 적어지는 경향이었다. 이상의 연구결과를 종합해 보면 폐쇄형식물생산시스템을 이용하여 분무경재배용 경삽묘를 생산할 경우, 육묘에 적합한 LED 광도는 60 μmol·m^-2·s^-1라고 판단되었다.

• Journal of Biosystems Engineering
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• 제33권5호
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• pp.362-369
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• 2008

There is developing interest in precision agriculture in Korea, despite the fact that typical Korean fields are less than 1 ha in size. Describing within-field variability in typical Korean production settings is a fundamental first step toward determining the size of management zones and the inter-relationships between limiting factors, for establishment of site-specific management strategies. Measurements of rice (Oriza Sativa L) yield, chlorophyll content, and soil properties were obtained in a small (100-m by 30-m) Korean rice paddy field. Yield data were manually collected on 10-m by 5-m grids (180 samples with 3 samples in each of 60 grid cells) and chlorophyll content was measured using a Minolta SPAD 502 in 2-m by 2-m grids. Soil samples were collected at 275 points to compare results from sampling at different scales. Ten soil properties important for rice production in Korea were determined through laboratory analyses. Variogram analysis and point kriging with and without median polishing were conducted to determine the variability of the measured parameters. Influence of variogram model selection and other parameters on the interpretation of the data was investigated. For many of the data, maximum values were greater than double the minimum values, indicating considerable spatial variability in the small paddy field, and large-scale spatial trends were present. When variograms were fit to the original data, the limits of spatial dependency for rice yield and SP AD reading were 11.5 m and 6.5 m, respectively, and after detrending the limits were reduced to 7.4 m and 3.9 m. The range of spatial dependency for soil properties was variable, with several having ranges as short as 2 m and others having ranges greater than 30 m. Kriged maps of the variables clearly showed the presence of both large-scale (trend) variability and small-scale variability in this small field where it would be reasonable to expect uniformity. These findings indicate the potential for applying the principles and technology of precision agriculture for Korean paddy fields. Additional research is needed to confirm the results with data from other fields and crops.d similar tendency with the result for the frequency less than 20 Hz, but the width of change was reduced highly.

• 생물환경조절학회지
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• 제16권3호
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• pp.240-246
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• 2007

돌나물의 수확후 저장온도가 저장성에 미치는 영향을 분석하기 위하여 저장온도에 따른 생체중, 색상차, 엽록소 함량, 수분함량, 외관상 변화 등을 조사하였다. 생체중은 저장온도에 따라 8.7-25.3%의 감소를 보였으며, 저장온도가 높을수록 생체중 감소율도 높았다. 계통에 따른 생체중 감소는 포항지방종이 가장 컷으며, 완주 지방종의 변화가 비교적 적었다. 외관상 품질은 $20^{\circ}C$에서 4일경, $10^{\circ}C$에서 6일경, $5^{\circ}C$에서 8일경부터 하위 잎에 변색이 나타나기 시작하였으며, 시간이 지남에 따라 서서히 부패하기 시작하였다 SPAD 값으로 비교한 엽록소 함량은 $20^{\circ}C$와 $10^{\circ}C$에서는 4일과 6일 후부터 급격한 감소를 보였으나, $5^{\circ}C$에서는 변화가 적었다. 잎의 색도 변화에서 명도를 나타내는 L값과 녹색-적색을 나타내는 a값은 저장온도가 높을수록 저장일 수에 따라 유의하게 증가하였다. 저장 후 10일째에 변색이나 부패한 돌나물의 비율은 저장온도가 높을수록 증가하였으며, 이는 수확시의 수분함량과 유의한 상관 관계를 보였다(P=0.01). 계통간에는 완주 지방종이 비교적 저장성이 높았으며, 군산, 완도, 포항 순으로 부패율이 높았다. 따라서 돌나물을 스치로폼 접시에 랩포장 할 경우, $5^{\circ}C$에서는 수확 후 8일까지 상품성을 유지한 상태로 저장이 가능하였다.

• 유기물자원화
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• 제27권4호
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• pp.15-24
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• 2019

본 실험은 방울토마토(Lycopersicon esculentum var. cerasiforme) 농가에서 자가제조한 토착미생물 액비를 3년 및 5년간 연용 처리하였을 때 토양 화학성 및 미생물상과 작물의 생장에 어떠한 영향을 미치는지를 비교하고자 수행하였다. 실험구는 3-year IM(토착미생물 3년 노지 처리구), 5-year IM(토착미생물 5년 노지 처리구), EM(effective microorganisms; EM 10년 온실 처리구)으로 분류하였고, 모두 1,000배로 희석하여 웃거름으로 관주하였다. IM과 EM 액비 자재의 pH 수준은 16주간 증가하였고 특히 EM의 pH는 1.2정도 상승하였다. IM 자재의 EC는 약간 높았지만 EM과 비슷한 수준인 0.2 dS/m으로 나타났다. 온실 내 포트 실험에서는 IM으로 처리된 토마토 뿌리의 건물중이 크게 증가하였다. 액비 처리에 따른 농가 현장 실험에서는 IM 액비 처리구의 pH는 7.5로 높았고 EC도 8.4 dS/m로 염류 과잉 수준을 보였다. EM 처리구의 유기물함량은 62 g/kg으로 가장 높았고 전질소 등 필수 무기성분 농도를 증가시키는데 영향을 끼쳤다. 하지만 IM 처리구에서도 토마토 생장을 위한 적절한 토양 화학성 수준이 관찰되었다. EM 처리구에서 세균수와 방선균수가 가장 증가하였다. EM으로 처리된 작물의 대량 무기성분 농도는 인산을 제외하고는 높게 나타났고 3-year IM과 5-year IM 처리구에서는 비슷한 무기성분 농도가 관찰되었다. 잎의 SPAD와 PSII 수준은 3-year IM 처리에서 낮게 나타났다. 토마토 작물의 엽폭, 엽장, 엽수, 수관면적, 초장, 경경은 생육 중기에는 EM 처리구에서 높은 수준이었으나 생육 후기에는 처리구 간에 비슷하였다. EM 처리로 잎 건물중은 IM 처리보다 2배 이상 높았지만 수확과수는 2배 이상 감소되었다.