• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.214-220
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• 1999

Rice production in Korea has markedly increased during the last two decades due to newly developed high yielding varieties and improved production technology. This experiment was conducted to determine the potential of tropical japonica germplasm in enhancing the yield of temperate japonica. The yield performance of two tropical japonicas (IR 65597-29-3-2 and IR66154-52-1-2) and one temperate japonica (Dongjinbyeo) was compared at different plant densities and nitrogen levels under Korean environmental conditions. Although tropical japonicas showed low tillering habit and large panicles, they had similar leaf area index and dry weight at heading stage to Dongjinbyeo of the high tillering type indicating that there was not much difference between tropical and temperate japonica in terms of biomass production. The highest milled rice yield of 6.15 t/ha was obtained from Dongjinbyeo at a high nitrogen level with less planting density (220 kg N/ha and 30 $\times$ 15 cm). However, those of the two tropical japonicas were 5.36 t/ha at the condition of 165 kg N/ha and 30 x 10 cm planting density and 5.06 t/ha at the condition of 165kgN/ha and 15 x 15 cm planting density, respectively. Ripened grain of tropical japonicas ranged from 65 to 87%, while that Dongjinbyeo ranged from 82 to 97% under Korean conditions.

• KSBB Journal
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• v.30 no.3
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• pp.97-102
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• 2015

This study aimed to evaluate the potential plantgrowth promoting effects of potassium polyacrylate, a superabsorbent polymer, and Bacillus sp. SH1RP8, a family of plant-growth-promoting bacteria. Potassium polyacrylate was selected as the polymer for use due to its high molecular weight and its ability to retain and continuously supply moisture. Plant-growth-promoting rhizobacteria (PGPR) were isolated from the soil and applied to plants growing in dry environments, such as saline conditions. The moisture absorption and retention abilities of potassium polyacrylate were evaluated at a high temperature ($50^{\circ}C$) and in a dry condition, during which time the polymer showed a water retention potential of 19606.07% after 29 days. To overcome the reaming problem in the soil environment, natural polymers (such as cellulose) were mixed with the potassium acrylate. The shoot growths of Peucedanum japonicum Thunb and Arundo donax were significantly enhanced when treated with the mixture of the isolated rhizosphere bacterium SH1RP8 and potassium polyacrylate (63.5 and 124.3%, respectively).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.196-199
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• 2005

This study was conducted to find out the effect of quality of water for wasabi growth by the relationship of quality of water and plant growth. In dissolved contents of water, water of lime area was higher than basalt area at $NO_3$, Cl, Ca, and Mg. In the change soil hardness and water temperature, basalt area was lower than lime one, during wasabi cultivation. Growth characteristics and yield were higher in basalt area than lime one. The weight of rhizome in basalt and lime was 585 kg/10a, 4183kg/10a, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.1
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• pp.4-10
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• 1999

This study was conducted to determine the effects of NaCl stress on nitrogen, ${NH_4}^+$, and ${NO_3}^-$ content of 4 barley cultivar seedlings that were cultured for 10 and 30 days with different NaCl levels (0, 50, 100, and 150 mM) contain-ing 1/4 Hoagland solutions. The sodium ion content in the shoot of barley seedlings sharply increased with an increase of NaCl concentration. After 30 days of NaCl treatment, the sodium content of the shoot at 150 mM NaCl was 27 times higher than in non-saline conditions. The sodium content in the root linearly increased with increasing NaCl concentration. Nitrogen content in the shoot linearly increased with increasing NaCl concentration, but nitrogen content in the root declined above the point where the $Na^+$ content was 3.0 mM/g $Na^+$ in the barley seedling. ${NO_3}^-$ content also decreased with increasing NaCl concentration. ${NH_4}^+$ content in the shoot decreased with NaCl condition, but its content in the root increased with NaCl condition. A positive correlation between ${NO_3}^-$ and ${NH_4}^+$ content was found in the shoot, but their relationship was negative in the root.

• Korean Journal of Medicinal Crop Science
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• v.9 no.2
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• pp.166-172
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• 2001

This study was conducted to investigate the optimum condition of breaking dormancy and to increase the germination rate of Hovenia dulcis Thunb. seeds. Germination of seeds which did not germinate at the various constant temperature was induced by the artificial breaking of seed coat, and the germination rate of seeds which the seed coats were broken was the highest(94%) at $15^{\circ}C$. The germination rate of seed was highest when seeds were treated with concentrated $H_2SO_4$ for 40 minutes. When seeds were stored in dry condition, the germination capability was maintained up to 5 years after harvest. However, their germination rate become lowered and average germinating duration was extended. Germination rate of seeds which were stored for 5 years significantly increased by the low temperature treatment more than 30 days.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.4
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• pp.19-25
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• 1979

Lowland and upland rice were grown under the both of lowland and upland conditions. Ecological variations in plant characteristics such as plant height, leaf emergence, length of leaf blade, leaf angle, leaf width, heading date, culm length, panicle length and straw weight were observed. Plant height, leaf emergence and heading were accelerated under the lowland condition for both lowland and upland varieties, while leaf length, leaf angle, leaf breadth, number of leaves were increased in upland condition for both lowland and upland varieties.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.1
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• pp.89-97
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• 2015

This study is to assess the effect of non-point source pollution discharge loads between tillage and no-tillage applications for upland crop areas using SWAT (Soil and Water Assessment Tool) watershed modeling. For Byulmi-cheon small rural catchment ($1.17km^2$) located in upstream of Gyeongan-cheon watershed, the rainfall, discharge and stream water quality have been monitored in the catchment outlet since 2011. The SWAT model was calibrated and validated in hourly basis using 19 rainfall events during 2011-2013. The average Nash-Sutcliffe model efficiency and $R^2$ (determination coefficient) for streamflow were 0.67 and 0.79 respectively. Using the 10 % surface runoff reduction from experiment results for no-tillage condition in field plots of 3 % and 8 % slopes under sesami cultivation, the soil saturated hydraulic conductivity for upland crop areas was adjusted from 0.001 mm/hr to 0.0025 mm/hr in average. Under the condition, the catchment sediment, T-N (total nitrogen, TN), and T-P (total phosphorus, TP) discharge loads were reduced by 6.9 %, 7.4 %, and 7.7 % respectively.

• Korean Journal of Medicinal Crop Science
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• v.13 no.6
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• pp.213-216
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• 2005

To develop a new anti-skin aging cosmetics or functional foods by using elastase inhibitor, a potent elastase inhibitor was screened from various extracts of medicinal plants and its optimal extraction condition was investigated. Methanol extracts of Rubi fructus showed the highest elastase inhibitory activity of 85%. The elastase inhibitor of Rubi fructus was maximally extracted when it was treated with 80% methanol at $50^{\circ}C$ for 12hr and its elastase inhibitory activity $(IC_{50})$ was 0.52 mg.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.778-782
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• 1997

Effects of different water potential on the growth and aerenchyma development of Adlay(Coix lacryma-jobi L. var. mayuen) were studied under every 3 days intermittent irrigation as a control at different growth stages, flooded pot condition and drought. Adlay could not germinate in the anaerobic soil conditions with excessive moisture while it wasn't inflicted with moisture damage after sprouting. Sprouted adlay can grow under flooded soil moisture condition because it's root has orthostichy cell, ventilating structure and cortex. Proping or ventilating roots were generated from adlay grown under flooded pots. Drought damage inflicted at the heading stage was the most severe.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.296-313
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• 1982

At a time when world population and food supply are in a delicate balance, it is essential that we look at factors to improve this balance. We can alter the environment to better fit the plant's needs, or we can alter the plant to better fit the environment. Improved technology has allowed us to increase the yield level. For moderately detrimental weather events technology has generally decreased the yield variation, yet for major weather disasters the variation has increased. We have raised the upper level, but zero is still the bottom level. As we concentrate the production of particular crops into limited areas where the environment is closest to optimum, we may be increasing the risk of a major weather related disaster. We need to evaluate the degree of variability of different crops, and how weather and technology can interact to affect it. The natural limits of crop production are imposed by important ecological factors. Production is a function of the climate, the soil, and the crop and all activities related to them. In looking at the environment of a crop we must recognize these are individuals, populations and ecosystems. Under intensive agriculture we try to limit the competition to one desired species. The environment is made up of a complex of factors; radiation, moisture, temperature and wind, among others. Plant response to the environment is due to the interaction of all of these factors, yet in attempting to understand them we often examine each factor individually. Variation in crop yields is primarily a function of limiting environmental parameters. Various weather parameters will be discussed, with emphasis placed on how they impact on crop production. Although solar radiation is a driving force in crop production, it often shows little relationship to yield variation. Water may enter into crop production as both a limiting and excessive factor. The effects of moisture deficiency have received much more attention than moisture excess. In many areas of the world, a very significant portion of yield variation is due to variation in the moisture factor. Temperature imposes limits on where crops can be grown, and the type of crop that can be grown in an area. High temperature effects are often combined with deficient moisture effects. Cool temperatures determine the limits in which crops can be grown. Growing degree units, or heat accumulations, have often been used as a means of explaining many temperature effects. Methods for explaining chilling effects are more limited.