• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.3
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• pp.3840-3847
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• 1975

With 30 excisting reservoirs in the Chin-Young area, the Sedimentation of the reservoirs has been calculated by comparing the present capacity with the original value, which revealed its reduced reservoir capacity. The reservoirs has a total drainage area of 3l4l ha, with a total capacity of 43.23 ha-m, and are short of water supply due to reduction of reservoir capacity, Annual sedimentation in the reservoir is relation to the drainage area, the mean of annual rainfall, and the slop of drainage area. The results of obtained from the investigation are summarized as follows: (1) A Sediment deposition rate is high, being about 7.03㎥/ha of drainage area, and resulting in the overage decrease of reservoir capacity by 16.1%. This high rate of deposition coule be mainly attributed to the serve denudation of forests due to disorderly cuttings of tree. (2) An average unit storageof 116mm as the time of initial construction is decreased to 95.6mm at present. This phenomena cause a greater storage of irrigation water, sinceit was assumed that original storage quantity itself was already in short. (3) A sediment deposition rate as a relation to the capacity of unit drainge area is as follow: Qs=1.27(C/A)0.6 and standard deviation is 185.5㎥/$\textrm{km}^2$/year. (4) A sediment deposition rate as a relation to the mean of annual rainfall is as follow: Qs=21.9p10.5 and the standard deviation is 364.8㎥/$\textrm{km}^2$/year. (5) A sediment deposition rate as a relation to the mean slop of drainage area is follow: Qs=39.6S0.75 and the standard deviation is 190.2㎥/$\textrm{km}^2$/year (6) Asediment deposition rate as a relation to the drainage area, mean of rainfall, mean of slope of drainage area is: Log Qs=0.197+0.108LogA-6.72LogP+2.20LogS and the standard deviation is 92.4㎥/$\textrm{km}^2$/year

• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.4
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• pp.23-44
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• 1988

The evaportranspiration of upland crops was measured by four types of lysimeter and water consumption characteristics together with the optimum irrigation point by the crops was defind. Among the evapotranspiration estimation formulas, the constant of wind function in the modified Penman equation was corrected to agree with the meteorological conditions of Korea. The evapotranspiration of the crops in the project standard year was estimated according to the cropping system of the project area in Chungju, and from the estimated evapotras - spiration, net duty of water per one time and irrigation in tervals were investigated. The results obtained are summarized as follows: 1. The evapotranspiration of the same crop measured at the same plot was slightly different by the lysimetric methods, and among the four types of lysimeter, the accuracy of the floating lysimeter was the highest. 2. The yields among the watering treatments showed the significance of 5% in the expe- riment with red cabbage and Chinese cabbage, and significance of 1% in the crisphead lettuce, and the optimum irrigation point for the tested crops was defined ad pF 2.0 by the least squre difference test. 3. The evapotranspiration of the crops in the mid-season stage showed maximum among the growing stages, and the average daily evapotranspiration by the crops over the growing seasons of cabbage, crisphead lettuce, Chinese cabbage, summer cucumber, tornato, salary and autumn cucumber was 4.18mm, 4.77mm, 3.9qrnm, 5.68mnn, joonim, 4.26mm and 3.3qrnn, respectively. 4. From the investigated soil moisture extration pattern(SMEP) of the crisphead lettuce, cucumber and tomato, the proportion of the first layer in the initial stage showed over so%, and the SMEP of the lowest fourth layer during the late-season stage in the experiment cabbage and Chinese cabbage was 15.8% and 16.9, respectively, with showed that the root elongated th the lowest soil layer. 5. The total available moisture(TAM) of clay loam was 21.2-23.3mm and that of sandy loam was 16.1 - 19.0mm under the optimum irrigation point of pF. 2.0, and the total readily available moisture( TRAM) of the crops cultivated in the clay loam soil was larger than that cultivated in the sandy loam soil, and the TRAM during the mid-and late-season were larger than that of the inital and crop development stage. 6. The estimated evapotranspration by the corrected Pennam equation, whkh corrected the constant of the wind function in the modified Penman equation, was nearly agreed with the actually measured evaporanspiration of grass. 7. Among the several evaportranspiration estimation methods, the evapotranspiration es- timated by the corrected Pennam equation was closed to the actual evapotranspiration of reference crop (grass) evapotranspiration, therefore it is suggested to use the corrected Penman equation to determine the duty of water of corps. 8. The average crop coefficient (Kc) of cabbage by the corrected Penman equation was 0.94 and that of crisphead lettuce, summer cucumber, tomato, salary, Chinese cabbage and autumn cucumber was 1.07, 1.22, 1.02, 1.01, 1.35, 1.09, respectively 9. The estimated total evapotranspiration of cabbage in the project area( Chungju) by the corrected Penman equation was 223.9mm and that of crisphead lettuce, Chinese cabbage, summer cucumber, tomato, salary and auturun cucumber was 215.7mm, 205.9mm, 359.Omrn, 300.9mm, 332.lmm and 202.7mm, respectively. 10. The net duty of water per one time of the crops cultivated in the sandy loam soil, and the net duty of water per one time in the mid-season & late-season showed larger than that of the initial stage. 11. The shortest irrigation interval of cabbage in the project area was 4.2 days, and that of crisphead lettuce, Chinese cabbage, cucumber, tomato and salary was 1.2days, 2.3days, 1.8days, 2.2days and 2.7days, respectively.

• Water Engineering Research
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• v.4 no.3
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• pp.111-126
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• 2003

Meteorological data are often needed to evaluate the long-term effects of proposed hydrologic changes. The evaluation is frequently undertaken using deterministic mathematical models that require daily weather data as input including precipitation amount, maximum and minimum temperature, relative humidity, solar radiation and wind speed. Stochastic generation of the required weather data offers alternative to the use of observed weather records. The precipitation is modeled by a Markov Chain-exponential model. The other variables are generated by multivariate model with means and standard deviations of the variables conditioned on the wet or dry status of the day as determined by the precipitation model. Ultimately, the objective of this paper is to compare Richardson's model and the improved weather generation model in their ability to provide daily weather data for the crop model to study potential impacts of climate change on the irrigation needs and crop yield. However this paper does not refer to the improved weather generation model and the crop model. The new weather generation model improved will be introduced in the Journal of KWRA.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1959-1963
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• 2006

As an alternative water resources development, wastewater reuse for agricultural and instream uses are expected to be fond of the limelight. In order to find the feasible reuse system scheme for reclaimed water in real field, existing reuse sites were investigated for water quantity, quality, and irrigation scheme. From the results, most of sites supplied reclaimed water with a request of the users(farmers) and reuse techniques for agricultural use were to be needed in the sites which supplied over yearly $1.0{\times}10^6$ ton as agricultural water.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.466-469
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• 2001

The effect of fertiltzer application on ponded and percolation water in paddies were evaluated at the experimental plots during irrigation period. We laid out three experimental plots such as 150% Excessive, 100% Standard and 70% Reduced. The concentration of T-N and T-P in ponded water were increased rapidly after application. The concentration of T-N and COD in percolated water increased with fertilizer application rates, while T-P concentration were almost constant.

• Journal of Life Science
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• v.9 no.6
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• pp.665-670
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• 1999

The effects of media, cell sizes and fertilizers on the early growth of Phalaenopsis plug plants were investigate. The sphagnum moss was more effective than other media in pink and white color cultivars. In comparison of different plug cell size, 50 cell size was more effective then 72 and 128 cell size in pink and white cultivar. In comparison of different fertilizer, margamf K in pink, and nutrient solution II(one time drenching with NHRI standard solution for three times irrigation) in white color cultivars was more effective then others, respectively.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.41-46
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• 1999

In the practice , ET was mainly estimated by Blaney-Criddle or FAO Penman method. But these methods were found to frequently overestimate ET. And calculation of effective rainfall by empirical formula is hardly to explain drop property and soil texture. Since 1990, FAO recommended the adoption of Penman-Moneteith combination method as a new standard for reference ET. Purpose of this study is establish new estimate method of upland crop requirements. We asopt P-M method to estimate ET and set up soil moisture balance equation to equation to calculate effective rainfall and irrigation water requirements. We expect that this new method rise efficiency to upland water management.

• KCID journal
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• v.18 no.1
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• pp.18-24
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• 2011

The suitable area of forage crop field was calculated under the assumption that all of the liquied manure would be used to nutrient of crops at the Saemangeum crop-livestock complex. At first, Korean cattle and dairy cattle were selected and swine was excluded becausr of high pollution availability. When forage crop was calculated from nutrient amounts of manure of livestocks and standard applicable fertilizer quantity to the selected forage crops, 232ha (278ha including infrastructure part) was determined to be appropriate in case of 2500 heads of Korean cattle and 300 heads of dairy cattle were raised. From the result by that calculated ares (232ha) to forage crop feeding could be possible to the Korean cattle and dairy cattle feeding using TDN index, more than 217ha of forage crop fields would be satisfied nutritionally.

• Korean Journal of Environmental Agriculture
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• v.18 no.1
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• pp.6-7
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• 1999

The water quality at Mankyeong River was surveyed 13 sites of main stream for 6 months from April to September in 1995 and 1997. The monthly average value of $NH_4-N$, $SO_4^{2-}$ and $Cl^-$ showed the highest peak in April while that of $NO_3-N$ showed the highest peak in August. The monthly average value of COD showed the highest peak in September at high temperature season. Concentrations of $NH_4-N$ and $SO_4^{2-}$ in Mankyeong River stream exceeded the standard water quality criteria in many sites. The water quality of Mankyeong River stream was not suitable for the irrigation source excepted the sites such as Hari, Gosan stream and Soyang stream. The floodgate of Mokcheon, Yocheon, Jeonju and Samcheon stream were rapidly polluted by the sewage of city, otherwise the Iksan stream was rapidly polluted by the sewage of swine. The sum of ionic concentrations in Mankyeong River stream was the highest at floodgate of Yocheon by influence of the sewage from city and industry. The order of the major anions and cations concentration in Mankyeong River stream were $SO_4^{2-}$ > $Cl^-$ > $NO_3-N$ > $SO_4^{3-}$ and $Na^+$ > $Ca^{2+}$ > $NH_4^+$ > $Mg^{2+}$ > $K^+$, respectively.

• Journal of Korean Society of Rural Planning
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• v.12 no.2 s.31
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• pp.49-56
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• 2006

The application of domestic wastewater on rice paddies results in the accumulation of sodium(Na$^+$) to the soil. Excessive concentration of sodium may cause the deterioration of the physical characteristics of the soil, change in the osmosis of the soil, destruction of soil aggregates as well as ion toxicity due to sodium accumulation. Using domestic wastewater as irrigation water should be preceded by measures to prevent or control the soil salinization caused by sodium. Agricultural reuse of domestic wastewater were found not to cause serious problems with food safety due to heavy metals. However, pre-treatment using ultraviolet or ozone is recommended to reduce the number of bacteria and gem and for public health reasons. Using domestic wastewater has shown that reducing the standard application of chemical fertilizers by as much as 50% reduced the harvesting index by only 10%. This study has shown that it is feasible to reuse domestic wastewater on rice paddies. In order to facilitate the application, it is deemed necessary to establish wastewater treatment technologies in the future, to review criteria for recycling domestic wastewater for agricultural purposes such as conditions of soil and cropping system and to resolve conflicts with farmers and public health issues.