• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1398-1402
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• 2005

Riverbank filtration is a natural process using alluvial aquifers to remove contaminants and pathogens in river water for the production of drinking water. In riverbank filtration, the understanding of contaminant transport is an important task for the production of high quality drinking water. This study investigates the transport behavior of hydrophobic organic contaminants when colloids (dissolved organic matter and bacteria) are present in the aquifer. A mathematical model for the transport of contaminants is developed and solved numerically for various situations. Results show that in the riverbank filtration the presence of DOM and bacteria enhances the mobility of contaminant significantly. Sensitivity analysis indicates that the distribution of the total aqueous Phase contaminant is significantly affected by distribution coefficients which account for affinity of solid or colloidal Phase to contaminant.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.3
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• pp.165-168
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• 1988

This study was conducted at the rice field of Livestock Experiment station, Suweon to investigate the effects of harvesting time on forage production and quality of rye (Secale cereale L.) on paddies. The results obtained are summarized as follows; 1. Fresh matter yield was peaked at the 10 days (May 10) after heading, however, dry matter yield was increased in proportion to maturity. 2. Digestibility (in vitro) showed the 83-77% by heading stage (Apr. 25-30) but decreased to 66-58% after heading stage. 3. Digestible yield reached to maximum level, 619.2 kg/lOa at the 10 days after heading (May 10). 4. The content of crude protein and crude fat in forage rye was decreased with advancing the maturity. 5. The lactic acid content of rye silage ranged from 1.3% to 2.0%.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.3
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• pp.309-310
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• 1989

• Proceedings of the Korean Society of Crop Science Conference
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• 1991.10a
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• pp.3-4
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• 1991

• Proceedings of the Korean Society of Life Science Conference
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• 2001.09a
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• pp.86-87
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• 2001

• Journal of the Korean Institute of Landscape Architecture
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• v.15 no.3
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• pp.51-69
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• 1988

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.2
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• pp.231-237
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• 1994

Three concentrations of P (0.33, 0.43 and 0.54%) and two concentrations of Ca (0.60 and 0.97%) in ration dry matter were evaluated for effects on dry matter intake and on milk yield and composition using 24 Holstein cows. Cows were arranged in a $3{\times}2$ factorial experiment as an incomplete randomized block design with three 28-day periods. Each cow consumed at least one ration with each concentration of Ca. Dry matter intake, yield of 3.5% Fat Corrected Milk, and milk composition were not affected by concentration of P, but milk yield was greater when lowest concentration of P was fed (22.8 vs. 22.1 kg/day; p<0.07). Cows fed rations containing 0.60% Ca had greater milk (22.7 vs. 21.9 kg/day; p<0.02) and 3.5% Fat Corrected Milk yields (p<0.03) and slightly greater protein content than when fed 0.97% Ca. Dietary Ca:P ratios between 1.1:1 and 2.9:1 had no effect on dry matter intake, milk yield, or composition. Concentrations of P in plasma were within the normal range for all rations. Because cows had high dry matter intake, mean daily intakes of both P and Ca were greater than required for their level of milk yield.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.648-657
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• 2015

Soil organic matter (SOM) plays an important role in the continuous production and environmental conservation in arable soils. In particular, the decomposition of organic matter in soil might promote soil organic matter and fertility due to the mineralization of N. In this study, to evaluate the effect of organic matter amendment on the C mineralization and N dynamic, $CO_2-C$ flux, extractable N and $N_2O$ emission were determined using closed chamber for 4 weeks at 10, 15, $20^{\circ}C$ of incubation temperature after the mixture of $2Mgha^{-1}$ rice straw compost and rye in sandy loam and clay loam. Regardless of soil texture, decomposition rates of rice straw compost and rye at $10{\sim}20^{\circ}C$ of incubation temperature ranged from 0.9 to 3.8% and 8.8 to 20.3%, respectively. Rye application in soil increased $NH_4-N$ and $NO_3-N$ content as well as the $N_2O$ emission compared to the rice straw compost. After incubation for 4 weeks, total C content in two soils was higher in rice straw compost than in rye application. In conclusion, application of rice straw compost and rye to soil was able to improve the soil organic matter and fertility. However, organic matter including the recalcitrant compounds like rice straw compost would be effective on the management of soil organic matter and the reduction of greenhouse gases in soil.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.2
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• pp.112-121
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• 1993

To study management practices suitable for the least production loss of temperate pasture under summer stress, two different cutting dates (late June and mid July) under summer stress and five different nitrogen treatment application levels (0, 100. 200, 300 and 400 kg/ha) were tried during the trial period between Oct. of 1986 and Oct. of 1989. The late June cutting showed a statistically significant increase of dry matter yield of pasture in comparison with the mid-July cutting(P<0.05). Nitrogen application also gave significant increase in dry matter yield. Botanical composition at the 4th cuttings in 1988 and 1989 was dominated by weeds to the level of 50%, Application ofnitrogen at 200 kgs per ha was found to be the best with production of grasses at 70%, legumes at 10 % and weeds at 20% in botanical composition comparison of pastures at the 4th cutting time the last year, showing a great decrease of weeds. K contents of pasture in June cuttings showed to be more than them in July cutting, and N and Na contents increased with increases of the nitrogen application level. It was concluded that treatment with June cutting and nitrogen application of 200 kg per ha was a way to keep temperate pasture from summer stress in the Cheju area.

• Journal of Plant Biology
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• v.13 no.1
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• pp.56-64
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• 1970

The present experiments differning from that conducted by agriculturists with the first consideration of food or seed production were performed in order to investigate the density effect on dry matter production in the artified population of maize. Three experimental plots were established and one seed was sown in the first plot, 2 seeds in the second plot and 3 seeds in the third plot, respectively. The space of each ridge was designed with 30cm in width and 50cm in length. The space of each seed was 4cm and the growth amount by density was measured through three times. The results obtained are as follows: 1) The total growth amount per unit area was in the order of the third, second and first plots until the second sampling. At the third sampling the whole plots showed almost the same growth amount except the first plot which showed a slightly smaller amount. 2) The growth amount per individual plant was in the order of the third, second and first plots until the second sampling, while the first plot showed drastic growth compared with the other two plots at the third sampling. 3) The growth amount by each organ(leaf, stem and root) of the plant body was markedly abundant in the stem of the non-productive part compared with that in the leaf of the productive part. Especially the root was affected remarkably by density and the first plot showed an abundant growth in comparison with the other plots which were too poor to resist the gound surface.