• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.395-398
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• 2004

Characteristics of concentration of pollutants such as total nitrogen(T-N), total phosphorus(T-P) and chemical oxygen demand(COD) during dry days of $2002\~2003$ were investigated for streamwater from a rural watershed. Water was sampled and discharge was measured at 5-days intervals at outlet of study area. The mean concentrations of pollutants in non-irrigation and irrigation period not significantly different. For increasing discharge in 2002, TN concentration increased but COD concentrations decreases.

• Magazine of the Korean Society of Agricultural Engineers
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• v.32 no.1
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• pp.72-86
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• 1990

This study was carried out to get the basic information of irrigation plans for upland crops such as the optimum irrigation level and the project water requirement. Red peppers and cucumbers were cultivated in PVC pot lysimeters filled with 60cm deep clay loam soil. Four tensiometers were installed in each pot to measure the soil water pressure head. Six levels of irrigation were used. The results obtained from this study are summarized as follows: 1.The optimum irrigation level. The irrigation level of FC-PF2.7 was found to be the optimum level for both red pepper and cucumber with respect to the yield and the weight per fruit. In case of FC-PF2.7, total ET during the irrigation period were 1005.2mm for red pepper, and 429.6mm for cucumber, respectively. 2.soil moisture extraction patterns. Average soil moisture extraction patterns (SMEP)during the irrigation period were from 1st soil layer 43% : 32% : 16% : 9% for red pepper and 39% : 34% : 15% : 12% for cucumber, respectively. The extraction ratio of the upper soils showed very large values during the early stage of growth and decreased largely during the middle stage, and became larger in the last stage. 3.The project water requirement. Among the reference crop evapotranspiration(ETo) computation methods presented by FAO, the Penman method was found to be the best. The effective rainfall was computed by a modified USDA-SCS curve number equation. Availability ratios of the total rainfall during irrigation season were 59.2% for red pepper and 48.9% for cucumber, respectively. Net project water requirement of design year are 837.3mm for red pepper. and 502.Smm for cucumber, respectively.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.1
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• pp.41-49
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• 2010

Return flow rate of irrigation water was estimated by water balance method. Daepyeong pumping district to irrigate 75.8 ha of rice paddy in the Geum river basin was selected to install gauging instruments to collect data such as weather, water levels, infiltration rate and evapotranspiration during irrigation season (May 27 to Sept. 20) in 2003 and 2004. Irrigation and drainage discharge were calculated from the rating curve and evapotranspiration was estimated both by the modified Penman formula and by the lysimeter. The results were as followed : 1. Total amounts of pumping water during irrigation season were $1,076,000\;m^3$ in 2003 and $1,848,000\;m^3$ in 2004. Total amounts of rainfall were 1336.0mm and 1003.0mm respectively during the irrigation season in 2003 and 2004. 2. It was surveyed that the amount of infiltration was 196.5 mm (2.2 mm/day). The gauged evapotranspiration was 311.0 mm (3.5 mm/day) and the calculated evapotranspiration was 346.0 mm (3.9 mm/day) during irrigation period in 2003. It was surveyed that the amount of infiltration was 169.9 mm (2.4 mm/day). The amount of gauged evapotranspiration was 377.3 mm (5.3 mm/day) and the calculated evapotranspiration was 454.5 mm (6.6 mm/day) during irrigation period in 2004. 3. The rates of quick and delayed return flow were 52.4 % and 17.7 % respectively, and so return flow rate was 70.1 % in 2003. The rates of quick and delayed return flow were 45.4 % and 16.1 % respectively, and so return flow rate was 61.5 % in 2004. It means that average return flow rate in the Daepyeong pumping district was assumed to be 65 %.

• Korean Journal of Environmental Agriculture
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• v.38 no.3
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• pp.133-138
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• 2019

BACKGROUND: Production function gives the equation that shows the relationship between the quantities of productive factors used and the amount of product obtained, and can answer a variety of questions. This study was carried out to evaluate the relationship between irrigation water used for rice production and rice productivity by the production function which shows the mathematical relation between input and output. METHODS AND RESULTS: The statistical data on rice production and on the amount of irrigation water were used for the production function analysis. The analysis period was separated for 1966-1981 and 1982-2011, based on goal's change on agriculture from 'increasing food' to 'complex farming'. The relation between irrigation and yield considering production function is a short-term production function both before and after 1982. These results can be expressed by the sigmoid relation. When comparing the graphs of the two analyzed periods, there are differences in quantity between the maximum point and the minimum point during the same analysis period, which can be called an 'Irrigation Effect' by the difference of irrigation, and 'Technical Effect' by the difference by inputs like as fertilizers etc. CONCLUSION: The results could be useful as information for assessing the relationship between agricultural water and the productivity of rice and predicting rice productivity by irrigation water in Korea.

• Korean Journal of Environmental Agriculture
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• v.22 no.3
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• pp.192-196
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• 2003

Objective of this study was to investigate the influences of harvest index and percolation water quality as irrigated the discharge waters from an industrial and a municipal wastewater treatment plants and seawater (1:5 seawater: tap water) as alternative water resources during tillering stage for drought stress. There were four different treatments such as the discharge water from an industrial (textile dyeing manufacture plant) wastewater treatment plant (DIWT), discharge water from the municipal wastewater treatment plant (DMWT), seawater (1:5) and groundwater as a control. For the initial chemical compositions of alternative waters, it appeared that higher concentrations of COD, $Mn^{2+}$, and $Ni^+$ in DIWT were observed than reused criteria of other country for irrigation, and concentrations of $EC_i$, Cl, and $SO_4$ in seawater were higher than that for irrigation. Harvest index was not significantly different between DIWT and DMWT with different irrigation periods in two soil types, but that of seawater (1:5) is decreased with irrigation periods in clay loam soil and not different between 10 days and 20 days of irrigation periods in sandy loam soil. For percolation water qualities, values of sodium adsorption ratio (SAR) are increased with prolonging the irrigation periods of seawater (1:5) and DIWT, but those of DMWT were almost constant through the cultivation periods regardless of the irrigation period in both soil types. EG of percolation waters is eventually increased with prolonging days after irrigation regardless of irrigation periods in both soil types. Therefore, it might be concluded that there was potentially safe to irrigate the discharge water from municipal wastewater treatment plant relative to harvest index, SAR and $EC_i$ values of the ground water through the rice cultivation period at tillering stage for drought period.

• Magazine of the Korean Society of Agricultural Engineers
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• v.27 no.1
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• pp.62-70
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• 1985

The purpose of this study is to investigate the basic data such the total, the daily maximum, and the peak stage of consumptive use of water and also the soil moisture extraction pattern for irrigation plan of tobacco during the growing period. The plots at which this study was conducted are divided into three fertilization levels of 30g, 60g, and 90g. Each block for three levels is divided as vinyl mulching and irrigation plot, vinyl mulching and nonirrigation plot, and nonmulching and irrigation plot. The results obtained are summarized as follows: 1. The evapotranspiration amount of mulching-irrigation plots are similar to that of mulching-nonirrigation plots. While, the evapotranspiration amount of mulching plots are different obviousely from that of nonmulching plots. Therefore, a significance was recognized between the mulching plots and the nonmulching plots. 2. The amount of evapotranspiration in case of 60g and 90g fertilization level was larger than that of 30g. But the 60g plots and the 90g plots showed little differences. 3. In the total amount of evapotranspiration for each of the experimental plots during the growing period, nonmulching-irrigation plot showed the largest value of 332.9mm, second the mulching-irrigation plot, 284. 9mm, and the mulching-nonirrigation plot, the smallest as 255. 9mm. 4. In the monthly average amount of evapotranspiration for each of the treatment plots, the mulching-irrigation the mulching-nonirrigation, and the nonmulching-irrigation plot showed 3. 6mm, 3. 2mm and 4. 2mm respectively. The daily maximum amount of evapotranspiration showed 5. 1mm, 4. 5mm, and 6.4mm for the mulching-irrigation, the mulching-nonirrigationl, and the nonmulching-irrigation plot respectively. 5. It was confirmed that the higher correlationship exists between the weight of dried leaves and the amount of evapotranspiration, and between the weight of dried leaves and the coefficient of evapotranspiration with the function of logarithms. The coefficient of evapotranspiration have a tendency to increase in proportion to the leaf area index. 6. The maximum coefficient of evapotranspration and the largest leaf area index showed 1. 45 and 5.5 respectively. The stage appeared maximum values was assumed to be before and after flowering. 7. The soil moisture extraction pattern has changed by the depth of root zone for the tobacco's growing. The soil moisture extraction influenced on the 20cm depth of soil after 15 days passed, the 30cm depth after 25 days passed and the whole root zone after 45 days passed from planting. It was shown in the only mulching-irrigation plot after S5days passed from planting that the rate of soil moisture extraction of 20cm layer was larger than that of 10cm layer.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.674-683
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• 2017

The frequency and intensity of soil moisture stress associated with climate change has increasing, and the stability of field crop cultivation has decreasing. This experiment was conducted to investigate the effect of soil moisture management method on growth and yield of corn. Soil moisture was managed at the grade of WSM (wet soil moisture, 34.0~42.9%), OSM (optimum soil moisture, 27.8~34.0%), DSM (dry soil moisture, 20.3~27.8%), and ESM (extreme dry moisture, 16.6~20.3%) during V8 (8th leaf stage)-VT (tasseling stage). After VT, irrigation was limited. The treated amount of irrigation was 54.1, 47.7, 44.0 and 34.5% of total water requirement, respectively. The potential evapotranspiration during the growing period was $3.29mm\;day^{-1}$, and upward movement of soil water was estimated by the AFKAE 0.5 model in the order of ESM, DSM, OSM, and WSM. We could confirm this phenomenon from actual observations. There was no significant difference in leaf characteristics, dry matter, and primary productivity depending on the level of soil moisture, but leaf development was delayed and dry weight decreased in DSM. However, dry weight and individual productivity of DSM increased after irrigation withdrawal compared to that of OSM. In DSM, ear yield and number of kernels per ear decreased, but water use efficiency and harvest index were higher than other treatments. Therefore, it is considered that the soil moisture is concentratedly managed before the V8 period, the V8-VT period is controlled within the range of 100 to 500 kPa (20.3~27.8%), and no additional irrigation is required after the VT.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.827-831
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• 2008

In this study, the effects of reclaimed wastewater irrigation on the concentration of heavy metals such as lead, zinc, cadmium, and copper in soil and vegetables were investigated by monitoring an experimental area irrigated with reclaimed wastewater. Three treatments and three replications on $10{\times}2$-m plots were installed and heavy metal concentrations in soil and vegetables were monitored from 2005 to 2007. The treatments applied in this study were groundwater irrigation (control treatment), wastewater irrigation, and irrigation with filtered reclaimed wastewater treated with ultraviolet light. The monitored results showed that the concentrations of Cu, Cd, and Pb in soil during the experimental period were lower than initial soil levels before irrigation, whereas Zn increased in all treatment plots. However, the ranges of Zn, Cu, Cd and Pb in soil were below the soil pollution standards in the Republic of Korea. Heavy metal concentrations in vegetables showed insignificant variations for all treatments.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.4
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• pp.17-26
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• 2017

In this study, EPANET model which is using on the pipe network analysis was applied to Haenam irrigation district has provided irrigation water by pipeline system about 1,125ha and then have built pipe network to study area and supply performance evaluation of existing structure was analyzed by SPA (Single Period Analysis) in EPANET. As model results of simulation average ratio of maximum supply quantity/irrigation water requirements(base demand) was analyzed by 2.63. It means also that was analyzed as being capable of ensuring the water supply capacity. It was provided the necessary information for the maintenance facility through analyzed hydraulic behaviors in the pipeline inside such as flow velocities, pressures and hydraulic grade lines. It was satisfied with the allowable design criteria that was compared analyzed results with presented allowable design standards at agricultural production infra improvement project planning and design (Pipeline design standard). In order to analyze efficiency promotions of irrigation water, using Extended Period Simulation it was compared supply quantity with irrigation water requirements while pumps set operating pattern in 24 hours, then efficiency promotions of irrigation water was determined through analyzed oversupply water quantity and occurrence time by branch lines. According to results for oversupply quantity in Haenam district by time and end of branch lines efficiency promotions of irrigation water was suggested from 0.33 % to 37.59 %. To draw reasonable operating rules for water use and through this research, it is expected to be helpful for efficient water use and operational management of agricultural pipeline system to the current agricultural irrigation.

• Journal of Biosystems Engineering
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• v.14 no.2
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• pp.128-136
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• 1989

The purpose of this study was to develop a computer operated automatic drip irrigation system for application in vinyl-house cultivation. The results can be summarized as follows: 1) The T-type ice compensation wire was used to measure the temperature. The voltage level measured up to 0.02 volt was used as input to an 8-bit A/D converter. 2) A specially devised tensiometer was used to content the watering system. When the needle of the pressure gauge reaches the lower threshold position it turns on the pumping system and turns off when it reaches higher threshold position. 3) In order to use the multiple gypsum blocks for one transducer, reed relays and a D/O board were used to make the sequential switching possible. 4) It was possible to automate the trickle irrigation system for the whole growth period of vinyl-house crops with the help of microcomputer. 5) In terms of furrow irrigation, the irrigation water consumption was the smallest, 2.8 times less than conventional method of surface trickle irrigation, 3.4 times less than subsurface trickle irrigation method. 6) In terms of productivity of cucumber, there was a drop in productivity when compared to furrow irrigation method, 7.2% for surface trickle irrigation, 27.4% for subsurface irrigation method.