• Weed & Turfgrass Science
• /
• v.6 no.3
• /
• pp.203-211
• /
• 2017

This study was conducted to investigate the phytotoxicity of main rice varieties and control efficacy of HPPD inhibitor to major paddy weeds at the time of temperature rise due to climate change. Phytotoxicity of herbicide to rice was increased as temperature was increased, and more severe in root than shoot. The phytotoxicity of japonica rice cultivars for the rice were mild enough to recover. However, glutinous rice, super high yield rice, and Tongil rice varieties were damaged enough to decrease the yield. Shindongjinbyeo transplanted by June 15, showed phytotoxicity enough to recover. However, in the rice field on June 30 and on July 15, the rice showed a remarkable inhibition. The control effect of Monochoria vaginalis and Scirpus juncoides was more than 90% under the temperature condition controlled artificially. However, Echinochloa oryzicola was controlled 40% at $27.5^{\circ}C$, which is a high temperature condition. In rice fields with different transplanting times, annual weeds except for E. oryzicola were highly controlled by 90% or more regardless of the time of transplanting.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.62 no.3
• /
• pp.193-202
• /
• 2017

This study was carried out in 2014 and 2015 to investigate the effect of transplanting density on panicle production and to analyze the relationship of panicle production with yield traits in the mid-maturing quality rice cultivar 'Haiami' in the mid-plain area of Korea. Number of tillers per square meter increased by reducing planting distance and increasing seedling number per hill. These effects were maintained until maturity and were reflected in the final number of panicles per square meter, although the effect of planting density decreased as rice growth progressed. However, increased panicle number per square meter following dense planting did not improve head rice yield. Panicle number per square meter was negatively associated with spikelet number per panicle and was not correlated with other yield components or head rice yield. Head rice yield was not correlated with head rice percentage but was closely and positively correlated with milled rice yield. Milled rice yield did not increase with grain filling percentage but increased with spikelet number per square meter. Spikelet number per square meter increased with both spikelet number per panicle and panicle number per square meter, although the former had a greater influence. Therefore, we conclude that head rice yield of the 'Haiami' cultivar grown in the mid-plain area of Korea is not improved with an increased panicle number following high planting density but it could be improved with high milled rice yield by increasing spikelet number per unit area.

• Horticultural Science & Technology
• /
• v.32 no.5
• /
• pp.590-599
• /
• 2014

This study was conducted to compare the cold tolerance of seven ground cover species, Orostachys japonica, Sedum oryzifolium, S. kamtschaticum 'SG1', S. reflexum, S. rupestre 'Blue Spruce', S. spurium 'Green Mental', and S. takesimense, which have been used for green roof and wall systems in Korea. Plants were grown in 10-cm pots and 1 g of tissues at stem-end and crown of each species were kept under either light or dark condition, respectively. For cold tolerance tests, plants were initially left at $4^{\circ}C$ and linearly cooled to 0, -4, -8, -12, -16, and $-20^{\circ}C$ at $-2^{\circ}C{\cdot}h^{-1}$ rate. Low temperature injury and regrowth rates were visually evaluated and assessed by image analysis, respectively. The lethal temperature ($LT_{50}$) of plant species was determined using electrolyte leakage measurements. S. reflexum was the most cold tolerant, showing the most survival at $-16^{\circ}C$, whereas S. oryzifolium and S. takesimense showed low temperature injury at $-8^{\circ}C$. Similar results were found with electrolyte leakage measurements at the stem end. For each species, the crown (Mean $LT_{50}:\;-12.15^{\circ}C$) was more cold tolerant than the stem end (Mean $LT_{50}:\;-10.47^{\circ}C$). In conclusion, S. reflexum and S. rupestre 'Blue Spruce' are recommended for planting in the central region of Korea during late fall and early winter, as they were more cold tolerant and showed more vigorous regrowth than the other tested plant species.

• Journal of Korean Society of Forest Science
• /
• v.78 no.3
• /
• pp.280-286
• /
• 1989

The present study was to examine the effects of light, temperature, and water stress on the photosynthesis and respiration rates and its seasonal changes in 3-Year-old Fraxinus rhynchophylla and Fraxinus mandshurica seedlings raised in pot in nursery. The results obtained are as follows: 1. The estimated light compensation points at which net photosynthesis approached zero were 35 and $28{\mu}Em^{-2}\;s^{-1}$ for F. rhyrachophylla and F. mandsdzurica leaves, respectively, The light saturation points occurred at $700{\mu}Em^{-2}\;s^{-1}$ in these species. 2. The maximum rates of net photosynthesis of leaves occurred at about $25^{\circ}C$ in F. rhynchophylla and at $20^{\circ}C$ in F. mandshurica. 3. The decrease in net photosynthetic rates of leaves began at -13 bars in F. rhynchophylla and -10 bars in F. mandshurica, and then its rates approached approximately zero at -23 bars in F. mandshurica and -29 bars in F. rhynchophylla. 4. The dark respiration rates of leaves were similar from $10^{\circ}C$ to $40^{\circ}C$ between these species, Also these increased from -10 bars to -28 bars, and then decreased remarkably in these species. 5. The net photosynthetic rates of leaves of F. mandshurica were higher than those of F. rhynchoplaylla until June, and after that lower than F. rhynchophylla. The dark respiration rates of leaves of F. rhynchophylla were higher than those of F. mandshurica from June to August, and After that similar between these species. 6. The respiration rates of stem and root were highest in April during the growing season. These values of F. rhynchophylla were slightly higher than those of F. mandshurica throughout the growing season.

• Journal of Bio-Environment Control
• /
• v.29 no.2
• /
• pp.161-170
• /
• 2020

There is systematic spatial variations in environmental properties due to sensitive reaction to external conditions at plastic greenhouse occupied 99.2% of domestic agricultural facilities. In order to construct 3 dimensional distribution of temperature, relative humidity, CO₂ and illuminance, measurement matrix as 3 by 3 by 5 in direction of width, height and length, respectively, dividing indoor space of greenhouse was designed and tested at experimental site. Linear regression analysis was conducted to evaluate optimal estimation method in terms with horizontal and vertical variations. Even though sole measurement point for temperature and relative humidity could be feasible to assess indoor condition, multiple measurement matrix is inevitably required to improve spatial precision at certain time domain such as period of sunrise and sunset. In case with CO₂, multiple measurement matrix could not successfully improve the spatial predictability during a whole experimental period. In case with illuminance, prediction performance was getting smaller after a time period of sunrise due to systematic interference such as indoor structure. Thus, multiple sensing methodology was proposed in direction of length at higher height than growing bed, which could compensate estimation error in spatial domain. Appropriate measurement matrix could be constructed considering the transition of stability in indoor environmental properties due to external variations. As a result, optimal measurement matrix should be carefully designed considering flexibility of construction relevant with the type of property, indoor structure, the purpose of crop and the period of growth. For an instance, partial cooling and heating system to save a consumption of energy supplement could be successfully accomplished by the deployment of multiple measurement matrix.

• Korean Journal of Food Science and Technology
• /
• v.31 no.6
• /
• pp.1523-1528
• /
• 1999

The consumer's demands for minimally processed fruits and vegetables have been increased rapidly because of its convenient handling, fresh-like quality as well as producing less wastes from the environmental point of view. Asian pears which are one of the main fruits widely produced and consumed in Korea easily lost their characteristics due to browning and softening after cutting. The objective of this study is to investigate the effects of various treatments on delaying deterioration of sliced Asian pears. 'Shingo' pear slices were treated with various solutions $(1%\;NaCl,\;0.2%\;L-cysteine,\;1%\;CaCl_2\;or\;1%\;calcium\;lactate)$ and were packaged with low density polyethylene $(LDPE,\;60\;{\mu}m)$, ceramic $(CE,\;60\;{\mu}m)$ or vacuum $(Ny/PE,\;80\;{\mu}m)$ film at $20^{\circ}C\;and\;0^{\circ}C$. In order to evaluate the quality of packaged sliced pears, quality index was determined in terms of color, firmness, soluble solids, titratable acidity. ascorbic acid, changes of gas composition, microbial test, and sensory quality. The results showed that sliced 'Shingo' pears packaged with CE and vacuum film maintained better quality than with LDPE at $0^{\circ}C\;and\;20^{\circ}C$. To retard browning and softening. 0.2% L-cysteine and 1% NaCl solutions applied for 1 minute were effective to reduce surface browning of sliced pears, and 1% $CaCl_2$ was the most effective to prevent softening.

• Journal of the Korean earth science society
• /
• v.39 no.5
• /
• pp.419-435
• /
• 2018

The purpose of this study is to understand meteorological and climatological factors that have influence on the garlic product in Seosan and Taean, and to analyze the economic value according to the use of climatical information data for garlic farmers. The climatological characteristics and trends in this area are analyzed using the meteorological data at the Seosan local meteorological agency from 1984 to 2013, the national statistical data for the product of garlic from 1989 to 2013, and the scenario data for climate change (RCP 4.5 and 8.5) for the period from 2001 to 2100. The results are as follows. First, the condition of lower temperature for garlic growth in winter season is satisfied with the mean air temperature. The wind speed are lower and stronger in Seosan and Taean than other garlic area. The suitable condition for the growth of northern type of garlic shows the decreasing trend in the accumulated precipitation in May. However, the area of growing the northern type garlic in the future is likely diminished because mean air temperature, accumulated precipitation, and mean wind speed are strong in the harvest time of garlic. Second, the seedtime of the northern and southern type of garlic using climate change scenarios (RCP 4.5, 8.5) in Seosan and Taean is getting late as time passes. and the harvest time gets faster, which indicates s that the period of garlic cultivation becomes shorter from 50 days to around 90 in the next 100 years. Third, the beginning days of white rot and delia platura of garlic are estimated by applying to the meteorological algorithm using mean air temperature and soil humidity. Especially, the beginning day of white rot garlic is shown to be faster according to the scenarios of RCP 4.5 and RCP 8.5. Fourth, the product of garlic (kg/10a) shows a high correlation with the minimum air temperature of a wintering time, the mean wind speed of a wintering time, the accumulated precipitation of a corpulent time, and the mean relative humidity of corpulent time of garlic. On the other hand, the analysis of garlic product when using the meteorological information data in cultivating garlic in Seosan and Taean reveals that the economic value increases up to 9% in total.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.9
• /
• pp.1452-1460
• /
• 2013

The purpose of this study was to investigate secondary drying effects on garlic quality, and to define the optimal secondary drying conditions for garlic preservation. The secondary drying tests used garlic that was naturally dried once and stored at low temperature. After secondary drying, the garlic was stored in a warehouse at room temperature. Tests were performed at different low-temperature storage periods (60, 105, 150, 195, and 240 days), secondary drying temperatures (35 and $40^{\circ}C$), drying times (1, 2, 3 days), and room temperature storage periods (15, 30, and 45 days). The results were compared with a non-secondary drying condition control. In general, the $40^{\circ}C$-2 days dry conditions showed the lowest weight-loss rate (5%) and rotting rate during room temperature storage. The sprouting rate increased by 20% during the initial 15 day-room temperature storage, along with a small increase after 30 days of room temperature storage. Increases in drying temperature and the period of secondary drying conditions caused a decrease in firmness. In addition, the sprouting rate was 10% higher, and rotting rate 5~10% higher, for the non-drying condition, compared to drying conditions. Based on our results, the $40^{\circ}C$-2 days drying condition is the optimal secondary drying condition for garlic storage.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.16 no.1
• /
• pp.27-35
• /
• 1988

Size characteristics of three widely used landscape trees were analized to establish a methodology of size prediction as time Passes. Tree height, tree width, stem diameter(breast or surface), canopy length and tree age were measured directly and indirectly(by using photograph), and the data were analized by using regression analysis through PC-SAS. The results are summarized as follows : 1. Zelkova serrata MAKINO showed relatively slow growth rate and the tree form was changed as aged. Size predictions were available by using the regression equations listed below : Surface diameter = 0.8293 x AGE Tree height = 0.4109(0.8293 x AGE) - 0.0039(0.7273 x AGE)$^2$Tree width = 0.3240(0.8293 x AGE) - 0.0024(0.1293 x AGE)$^2$Canopy length = 0.1337(0.8293 x AGE) - 0.0020(0.7293 x AGE)$^2$2. Pinus strobus L. showed relatively fast growth rate and the tree form did not change much as aged. Size predictions were available by using the regression equations listed below. Breast diameter = 0.756 x AGE Tree height = 0.7695(0.756 x AGE) - 0.0164(0.75\ulcorner x AGE)$^2$Tree width = 0.4331(0.756 x AGE) - 0.0079(0.75\ulcorner x AGE)$^2$Canopy length = 0.1365(0.756 x AGE) - 0.0032(0.75f x AGE)$^2$ 3. In case of Magnolia denudata DESROUX, tree form was determined relatively earlier than the other two species. Si2e predictions were available by using the regression equations listed below : Surface diameter = 0.88 x AGE Tree height = 0.5412(0.88 x AGE) - 0.0110(0.88 x AGE)$^2$ Tree width = 0.3752(0.88 x AGE) - 7.0061(0.88 x AGE)$^2$Canopy length = 0.1110(0.88 x AGE) - 0.0022(0.88 x AGE)$^2$ This study aimed to find a way to predict size change of landscaping plants. This methodology will be applied to a wide range of landscape plants to provide practical data to landscape designers.

• The Korean Journal of Pesticide Science
• /
• v.15 no.1
• /
• pp.55-60
• /
• 2011

To work out quality control methods of environmental-friendly organic materials (EFOMs), the reason and basis for EFOM-selection and farmer's favorite formulation type of EFOMs, etc were investigated on farmers who had been practicing environmental-friendly agriculture. EFOMs used were soil amendments, control agents of plant diseases and insect pests, plant growth promotion formulations, in turns. In EFOMs application time, 22.7% of farmers sprayed EFOMs without delay after they were bought, in other hand, 77.3% of farmers used EFOMs which had been bought and stored for some period. Microbial density on seventeen environmental-friendly microbial formulates (EFMFs) including microbial pesticides, a microbial fertilizer, and environmental-friendly organic materials was investigated at different storing temperature and shelf life. When the microbial density of EFMFs was investigated without delay after they were bought, all used microbial pesticides and a microbial fertilizer was confirmed to be optimal for the certified density but two of environmental-friendly organic materials was confirmed not to be optimal. When microbial density of 17 EFMFs were investigated after storing them for six months at $4^{\circ}C$, only one of 9 microbial pesticides was confirmed not to be optimal, the other hand four of seven environmental-friendly organic materials not to be optimal, which each of their microbial density was less than the certified density. Population dynamics of microbial agents was much more influenced in fluctuated temperature (room temperature) than in static temperature condition ($5^{\circ}C$ and $25^{\circ}C$). Shelf life of microbial agents according to microbial formulation type were high in granule type, liquid wettable type and liquid type in turns.