• Journal of Environmental Science International
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• v.23 no.4
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• pp.615-623
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• 2014

The groundwater level varies according to the characteristics and composite materials of aquifer. In this study, specific yield and reaction factor which are the major two hydrogeological parameters in the WTF(Water Table Fluctuation) method were estimated and analyzed spatial characteristics. 8 groundwater level stations which have enough measuring period and high correlation with rainfall in the Hancheon watershed were used. The results showed that specific yield was randomly distributed and reaction factor showed inverse trend with altitude. If the enough data were collected, reaction factor according to altitude in ungauged points could be estimated by using these parameter characteristics.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.195-202
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• 1995

This experiment was performed to characterize the optimum water table level for the growth and yield of barley(var. Olbori) and wheat(var, Grumil), Olbori and Grumil were grown in the 550 liter plastic pot filled with silt loam or sandy loam, During the whole growth period, the water table adjusted to be 20, 30, 40, 50, and 70cm, Higher water table was resulted in the decrease in plant height and top dry weight, but in the increase of the ratio of top to root dry weight, especially in barley, This suggested that high water table level affected more the growth of top than that of root, The number and area of green leaves were decreased as the water table was higher than 30 to 40cm at the late growth period(May 18, 1993), The largest number and area of green leaves were shown at 50cm of water table in sandy loam and at 70cm in silt loam, As the water table was high, the leaf chlorophyll content was low, And barley was affected more significantly than wheat by soil texture, The photosynthetic activity was decreased remarkably at 20cm water table, Heading period was 2 to 3 and 4 days earlier at the 20cm water table of sandy loam in barley and wheat, respectively, However this earlier heading was not shown in silt loam, Grain filling was accelerated 5 to 7 days earlier in barley and 10 days in wheat grown at 20cm water table, The highest yield was present at 50 and 70cm water table, The yield was decreased remarkably at 20cm water table, resulting that yield reduction ratio of barley was 71.1% and 72, 2%, and that of wheat was 41.0% and 60, 0% in sandy loam and silt loam, respectively, High water table decreased the number of spike per unit area, but increased the seed weight per spike in barley, However, High water table reduced the seed weight per spike in wheat. There was significant correlation between yield and leaf chlorophyll content in wheat and barley, Yield was correlated significantly with green leaf area in barley, and with top dry weight, ratio of top to root dry weight chlorophyll content and photosynthetic activity in wheat. The optimum water table was 50 to 70cm in wheat and barley, They grew fairly well at 30cm water table of sandy loam, and at 40cm of silt loam.

• Journal of the Korean Society of Tobacco Science
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• v.10 no.2
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• pp.99-107
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• 1988

Pot experiment was conducted to find out the effect of lime application on yield and chemical composition of burley tobacco in 1986, Lime increased exchangeable calcium and pH of soil, but decreased Al, Fe and Mn concentrations. Yield was increased by lime application, however lime could not be caused to yield increasing in the soil with high calcium contents. Cored leaves of limed Plot contained higher Mg. K, total nitrogen, NO3-nitrogen, water soluble and insoluble ash, alkalinity number of water soluble and insoluble ash, citric and malic acid, but lower Fe, Mn, protein-nitrogen, NH3-nitrogen, nicotine petroleum ether extract, palmitic and linolenic acid concentrations than those of unlined plot. The linoleic acid and volatile neutral constituents of cured leaves were not affected by liming. Lime increased yield, however it did not affect leaf duality in respect to chemical characteristics, suggesting that liming should be necessary for tobacco cultivation.

• Journal of Korean Society of Forest Science
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• v.57 no.1
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• pp.14-19
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• 1982

Fines in high-yield sulfite pulp have much higher water retention value as compared with fines in Stone groundwood pulp. Therefore, they are apt to adhere partially or entirely onto the fiber surface during the paper making. This tendency is greatly enhance with decrease of the pretreated yield and increase of the water retention value of fines. Fines, which adhere onto the fiber surface in paper, contribute to the light scattering of the paper. Accordingly, the specific scattering coefficient of fines in high-yield sulfite pulp is considerably lower than that of fines in stone groundwood pulp, which hardly adhere onto the fiber surface. The fact that high-yield sulfite pulp is inferior to stone groundwood pulp in opacity is explained on the basis of the high degree of swelling of fined in addition to the softening of fiber fraction.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.4
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• pp.783-787
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• 2009

A point-to-mesh type discharge system, utilizing a water-pen point as a corona discharge electrode and a mesh as an ion induction electrode, has been proposed, and the effect of the water-pen point electrode of the discharge system to the ionic wind velocity and generation yield was investigated. It was observed that the proposed discharge system with the water-pen point electrode can generate a higher ionic wind velocity as compared with that of the metal point electrode. As a result, the peak ionic wind velocities of 2.61 and 4.05 m/s for the positive and negative corona discharges of the proposed discharge system can be obtained, which are 1.39 and 1.15 times higher than those of the metal point electrode with same design. The ionic wind generation yield of 4.72 m/s/W of the discharge system with the water-pen point electrode was obtained for the positive corona, which was 3.66 times higher than that of the metal point electrode. This enhancement may be due to the effect of the water-pen point electrode.

• Korean Journal of Medicinal Crop Science
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• v.5 no.1
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• pp.1-6
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• 1997

The experiment was conducted to investigate the effect of water stress on yield and quality of Ligusticum chuanxiong Hort. The water stress treatment was imposed artificially on seedling, flowering and rhizome enlargement stage of the plant. The root yield rate decreased to 19.1%, 18.2% and by the water stress treatment at rhizome enlargement, seedling and flowering stage, respectively. Portion of the products having commercial quality grade (above 20g of rhizome weight) was 93.4% at control plot, while it was 85%, 81.7% and 78.3% when stressed for water at seedling, flowering and root enlargement stage, respectively. Content of extract was the higher in the order of control, water stressed at rhizome enlargement, flowering and the seedling stage. Postive correlationship was found between yield of rhizome and rootlet yield or economic production ratio, and between dry weight of stem and rootlet yield.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.2
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• pp.1-11
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• 2018

Probable Maximum Flood (PMF) is mostly applied for the designs of large-scale hydraulic structures and it is estimated by computing the runoff hydrograph where Probable Maximum Precipitation (PMP) is inserted as design rainfall. The existing PMP is estimated by transferring the heavy rainfall from all watersheds of korea to the design watershed, however, in this study, PMP was analyzed by selecting only rainfall events occurred in the design watershed. And then, Catchment-scale Soil Erosion Model (CSEM) was used to estimate the PMF and sediment-runoff yield according to the watershed-based estimated PMP. Although the PMF estimated in this study was lower than the existing estimated PMF in the Yongdam-dam basin, it was estimated to be higher than the 200-year frequency design flood discharge. In addition, sediment-runoff yield was estimated with a 0.05 cm of the maximum erosion and a 0.06 cm of the maximum deposition, and a total sediment-runoff yield of 168,391 tons according to 24-hour PMP duration.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.3
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• pp.153-157
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• 2001

To evaluate the effect of liquid pig manure application, the growth and yield of rice and the quality of infiltration water were investigated with application of different amounts of liquid manure. At this study, liquid pig manure was treated with 100, 200, 300 and 400% of recommending nitrogen fertilizer level, respectively. Liquid manure with application rate more than 200% of recommending N fertilizer level (11kg) caused to increase of plant height and number of tiller at panicle formation stage, but it caused the plant disease and pest and plant lodging. In those treatment, number of panicles per hill and number of spikelets per panicle were increased, but yield of rice was less than chemical fertilizer treatment due to low rate of ripeness and 1,000 grain weight. $NO_3-N$ concentration in infiltration water sample collected at 90 cm of soil depth was increased with increasing application amount of liquid manure. With liquid manure application more than 200% of recommending N fertilizer level, it affected negatively on yield and environment such as groundwater quality.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.3
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• pp.147-152
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• 2001

This study was carried out to investigate the effect of application time and amount of liquid pig manure on growth and yield of rice plant and infiltration water quality. Liquid manure treatment with higher application rate and closer application time to transplanting time showed higher plant height and number of tiller at panicle formation stage, but it caused the plant disease and pest and lodging. In liquid manure treatment with higher application rate, number of panicles per hill and number of spikelets per panicle were higher but yield of rice was less than chemical fertilizer treatment due to low rate of ripeness and 1,000 grain weight. $NO_3-N$ concentration in infiltration water sample was increased with increasing application amount of liquid manure and closer application time to transplanting of rice plant. With consideration yield of rice and environment such as groundwater quality, the proper application amount were 150% and 100% of recommending N fertilizer level (11kg) at before winter and April or May treatment, respectively.

• Horticulture, Environment, and Biotechnology : HEB
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• v.59 no.6
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• pp.815-826
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• 2018

The intense drought affecting olive production in Northern Chile underscores the need to research non-traditional irrigation strategies to obtain the best crop performance. Accordingly, this study aimed to obtain preliminary data to guide future research on this topic. Different water replenishment levels on crop evapotranspiration ($ET_c$ ; 13.5, 27.0, 40.5, and 54%) were established in a young orchard, cv. Arbequina, from the end of fruit drop (EFD) to full bloom in the next season. We evaluated the influence of plant water status (${\Psi}_{stem}$ ) and crop load, considered as function of fruit number divided by trunk cross-sectional area, on reproductive and productive variables using multiple linear regressions. Our results show that crop load and ${\Psi}_{stem}$ measured from EFD to harvest affected yield components. Nevertheless, ${\Psi}_{stem}$ had the strongest influence on fruit size, pulp development, oil accumulation, and yield. Oil content and yield were reduced by 54% and 50% for each MPa, respectively, from ${\Psi}_{stem\;EFD-H}$ -1.8 MPa, an effect that intensified as crop load increased. During the period of flower development (September-November), the number of flowers per inflorescence and percentage of perfect flowers were reduced when ${\Psi}_{stem}$ was less than -2.0 MPa. These preliminary results showed that bud differentiation, inflorescence and flower formation are highly sensitive to water deficit.