• Korean Journal of Agricultural Science
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• v.49 no.3
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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.

• Journal of Ginseng Research
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• v.15 no.1
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• pp.31-35
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• 1991

In order to know the optimum planting density under shading structures at different light intensity, We investigated the growth status, distribution of ginseng leaf area, correlation between planting density and root weight per plant and yield, correlation between leaf area index and root weight per plant and yield. According to the increase of planting density the leaf area per plant was decreased, but leaf area index (L.A.I) was increased. Ginseng leaf population at different lines under common straw shading were distributed mainly in frost lines but polyethylene net shading at 10fo light intensity were distributed equally in all lines. Optimum planting density in common straw shading at 5% light intensity was 55 plant per tan (90 cmX180 cm) and polyethylene net shading 81 10% light intensity was 60 plant per tan, in consideration of root weight and yield. Optimum leaf area index was 2.4 under common straw shading at 5% light intensity but was 2.7 under polyethylene net shading at 10% light intensity.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.6
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• pp.972-981
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• 1990

Many researchers have been interested in whether complex computational problems can be solved by the neural net or not. Especially, problems of early vision are integrated by Tikhonov's regularization theory. Regularization technique can be realized in resistive net. In this paper, we suggest the resistive net with upper and lower thresholder to be able to compute shape from shading and to solve its discontinuous problem. We simulate three algorithms-Horn's algorithm, resistive net and up-low thrwsholding net -with respect to three cases-fully boundary, boundary losing partly and noisy image. As being able to cope with crease and discontinuous parts, we get the good 3D shape from shading.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.584-589
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• 2014

Jeffersonia dubia is a spring-flowering perennial found in rich forests in Korea and Northern China and has potential as an ornamental or medicinal plant. However, illegal picking and land use change have decreased the number of populations and overall population size of this plant in its natural habitat. Although J. dubia has been reported to be a shade-preferring plant, no study has determined the optimum light intensity for its growth. The objectives of this work were to observe the effects of various shading levels on the physiological responses of J. dubia and to determine the proper shading level for cultivation. Treatments consisted of four shading levels (0%, 50%, 75%, and 95% shade) imposed using black mesh cloth. The number of leaves and dry weight increased with decreased shading. The shoot-to-root ratio increased with increased shading, mainly due to decreased root dry weight under shading. Plants showed low net $CO_2$ assimilation rates and $F_v/F_m$ values combined with low dry matter levels when grown under 0% shade (full sunlight). These results indicate that J. dubia plants experience excessive irradiance without shading, resulting in damage to the photosynthetic apparatus. By contrast, the net photosynthesis rate increased as the shading level increased. $F_v/F_m$, the potential efficiency of PSII, was 0.8 under 95% shade, indicating that J. dubia is well-adapted under heavy shading. However, the low dry matter of plants in the 95% shade treatment indicated that the low light intensity under 95% shade led to a decline in plant growth. Thus, moderate light (50% shading) is recommended for cultivating J. dubia without physiological defects.

• Korean Journal of Medicinal Crop Science
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• v.15 no.4
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• pp.276-284
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• 2007

To investigate the influence of shading materials with growing stages in Panax Ginseng C. A. Meyer, the diurnal change of photosynthesis, stomatal conductance, transpiration and its any correlation were measured. The net photosynthetic rate and stomatal conductance of ginseng were higher in the morning than in the broad day. The net photosynthetic rate was increased as the PAR (Photosynthetically Action Radiation) was increased and it was reached the maximum at the $200\;{\mu}mol/m^2/s$ of PAR in overall leaves. Transpiration rate was increased in the afternoon compared to in the morning. The transpiration rate was higher in rain shelter shading plate than in polyethylene net. A linear equation was obtained between net photosynthetic rate and stomatal conductance in the morning. SPAD was higher in rain shelter shading plate than in polyethylene net through all growth stages. It may result from the decrease of growth progress. From investigating photosynthetic characteristics, we concluded that shading plate of rain shelter was more an efficient material to ginseng growth.

• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.320-327
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• 2016

Allium hookeri is used for food and medical materials in Asia. This study was carried out to elucidate the effects of shading rates on growth and quality of A. hookeri cultivation in greenhouse. Treatments were given with 35%, 55%, 75% and 95% shading rates and non-shading (Control). Photosynthesis photon flux density (PPFD) of control, 35%, 55%, 75%, and 95% shading were 792, 515, 351, 182, and $78.2{\mu}mol{\cdot}m{\cdot}s^{-1}$ respectively. The emergence ratio was 98% under non-shading, 35% and 75% shading condition, and it was 100% under 55% and 95% shading condition on April 20, 2016. These results showed no correlation between emergence rate and shading treatment. When shading net was set up inside at greenhouse, fresh weights in control, 35%, 55%, 75%, and 95% shading treatments were 1,142, 3,511, 5,936, 6,408 and 3,779kg/10a, respectively. When shading net was set up outside at greenhouse, fresh weights in control, 55%, 75%, and 95% shading treatments were 1,372, 5,442, 6,238 and 3,595kg/10a, respectively. Dry weight, percentage of dry matter, number of leavesand branches, plant height and root length in 75% shading treatment were higher than other shading treatments. From these results, we suggested that the proper shading rate in a greenhouse is 75% for A. hookeri cultivation in middle area of Korea.

• FLOWER RESEARCH JOURNAL
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• v.19 no.1
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• pp.1-7
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• 2011

This study was carried out to establish a production system of cut flowers and bulbs of oriental hybrid lilies in highland in summer. In study, effect of cultivation type and shading was examined. The cultivation types used in the bulb production experiments were greenhouses with no cover, greenhouses with net screen (net screen house), and greenhouses with EVA roof cover and net screen sides (rain shelter house). Net screen and rain shelter houses had either 0 or 30% shading. Cultivation type had significant effect and shading had a minor effect on bulb production. The greatest yield and quality of produced bulbs were obtained in the rain shelter house with 30% shading. From the results of this study, it is concluded that dispersed production of high quality cut lily flowers and bulbs could be achieved during the summer in highland.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.292-298
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• 1997

To compare the growth pattern of ginseng plant under between conventional shading(light transmittance rate 3％) and polyethylene net shading(light transmittance rate 10％), the distribution of leaf area, specific leaf weight (S. L. W), leaf and stem dry weight and changes in light intensity were investigated in 2, 4 and 6 year old ginseng plant populations. Light transmittance rate(L.T.R.) was 3％ at front line, 2％ at middle line and 1.5％ at rear line under conventional shading but it was 12, 10 and 8％ under polyethylene net(P.E) shading, respectively. In 2 year old population, there was a little difference in the growth characteristics investigated between conventional and P.E. shading. In 4 year old field, the leaf area, stem and leaf dry weight decreased in large amount in the order of middle, and rear line on ridge under conventional shading, but with a little difference under P.E. shading. And these trends enlarged in 6 year old field with appearance of a large part of shoot over furrow from ridge planted ginseng. Root yield index was much lowered at the rear 3rd, 4th and 5th line of the conventional shading bed, but there was no yield difference among lines except 5th lines under the P.E. shading with higher yield by 28％ than conventional shading.

• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.249-254
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• 2016

This study was carried out to evaluate the efficiency of white shading agent for reduction of greenhouse air temperature and to develop cost-effective cooling strategies for strawberry seedling production during hot seasons. Experiment results showed that solar radiation ($W/m^2$) was reduced by 14~17% and 33~37% for 15% and 35% white wash shading treatments, respectively, in black shading net treatment solar radiation was reduced by 39~44% compared to non-shaded treatment. Measured greenhouse air temperatures in 15% and 35% white wash shading treatments were $38.4^{\circ}C$ and $36.5^{\circ}C$, respectively, whereas in black shading net covered greenhouses air temperature was $35.1^{\circ}C$, thereby 35% and 15% shading treatments showed 3.3 and $1.9^{\circ}C$ higher air temperatures than black net shading treatment. Crown diameter of strawberry plants in black net shading treatment was 7.5mm, and in 15% and 35% white wash shading treatments were 8.6mm and 8.3mm, respectively. Strawberry transplants grown in 35% white wash shading treatment produced the highest above ground fresh weight(7.8g), followed by 15% white wash shading(6.7g) and black net shading treatments(5.8g). Also, both 15% and 35% white wash shading treatments produced higher root fresh weight(4.1g and 4.3g) compare to black net shading treatments(2.7g).

• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.3
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• pp.122-127
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• 1987

This experiment was carried out to investigate the effect of shading degrees (0:full sunlight, 25, 50 and 75%) on the crop growth rate (CGR), net assimilation rate (NAR) and photosynthetic activity of grasses for obtaining the basic data on the development, management and utilization of pasture in the forest. For the test, different artificial shading houses were established and pasture species used in this study were orchardgrass, timothy, perennial ryegrass and ladino clover. The experiment was performed at Livestock Experiment Station, Suwon, in 1984-'85. The results obtained are summarized as follows. 1. The highest CGR was obtained at 0% (full sunlight) and 25% of shading, followed by 50 and 75% of shading degrees, in that order. CGR of orchardgrass and perennial ryegrass were higher than those of timothy and ladino clover. 2. NAR was significantly decreased as the shading degrees increased. The highest NAR was observed at perennial ryegrass plot. 3. The photosynthetic activity during summer season was the highest at 25% of shading, followed by 50, 0 and 75% of shading degrees. While, the photosynthetic activity during fall season was the highest at 25% of shading, followed by 50, 0 and 75% of shading degrees, in that order. Those of orchardgrass and perennial ryegrass were remarkably higher than that of timothy. 4. A significant positive correlation was obtained in the relationship between CGR and NAR of main grasses, regardless of pasture species and investigated date.