• 한국물환경학회지
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• 제20권6호
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• pp.597-602
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• 2004

Field experimental study was performed to examine characteristics of nutrient export from paddy rice fields with irrigation practices. Experimental fields with surface-water and ground-water irrigation were monitored and analyzed during rice culture period. The water balance showed that outflow generally balanced the inflow showing that about half (58~68%) of total outflow was lost by surface drainage. Water and nutrient export are more in surface-water irrigation paddy than in ground-water irrigation paddy. The reasons might be more irrigation water available and easy to use in surface-water irrigation. If irrigation water reduced, it could result in reduction of nutrient export in paddy rice fields, which can save water and protect water quality. However, deviation from conventional standard practices might affect the rice yield and further investigations are necessary.

• 한국농공학회논문집
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• 제66권2호
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• pp.13-24
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• 2024

This study aims to contribute to efficient paddy field water management by developing an IoT-based automatic paddy inlet that can consider water level changes according to variations in the supplied water quantity through irrigation channels. This IoT-based automatic paddy inlet not only ensures water level changes based on the supply of irrigation water but also secures irrigation efficiency. The effectiveness and efficiency of the developed IoT-based automatic paddy inlet were presented to contribute to efficient paddy field water management. As a result, the IoT-based automatic paddy inlet demonstrated the capability to maintain the optimal water level in the paddy field. Particularly, it exhibited up to 18.4% higher water resource usage efficiency compared to conventional paddy inlet, emphasizing the IoT-based automatic paddy inlet's advantage in terms of water resource usage.

• 농업과학연구
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• 제38권2호
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• pp.331-341
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• 2011

To provide variation of water supply for instream flow from reservoirs with various magnifications of paddy irrigation area to watershed area, 8 reservoirs were selected to draw operation rule curve and to analyze water supplies from reservoirs. Reliability of 90% for supplying irrigation water from reservoir was able to maintain and instream flow water was able to be supplied only in the reservoir with magnification of paddy irrigation area to watershed area above 3. The more magnification of paddy irrigation area to watershed area increased, the more ratio of irrigation water to total water storage decreased, and the more ratio of instream flow water to total water storage increased. From the heightening 113 reservoirs in Korea, annual irrigation water was estimated to 1,146.05 $Mm^3$ in normal operation, 839.57 $Mm^3$ in withdrawal limited operation, and annual instream flow water was estimated to 149.68 $Mm^3$ in normal operation, 283.19 $Mm^3$ in withdrawal limited operation. It was concluded that withdrawal limited operation was followed to have the premise of saving irrigation water, more instream flow water was able to be supplied from reservoirs with high magnification of paddy irrigation area to watershed area.

• 한국농공학회논문집
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• 제56권4호
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• pp.1-8
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• 2014

Appropriate amount of water supply to paddy fields in proper time is important to achieve efficient agricultural water management. The purpose of this study is to evaluate the irrigation water supply adequacy for paddy fields using water level data in irrigation canals. For the evaluation, the real-time water level data were collected from main canals in the Dongjin irrigation district for 2 years. Using the water level data, delivered irrigation water amounts at the distribution points of each canal were calculated. The water balance model for paddy field was designed considering intermittent irrigation and the irrigation water requirement was estimated. Irrigation water supply adequacy was analyzed from main canals to the irrigation blocks based on the comparison between estimated requirement and delivered irrigation water amounts. From the adequacy analysis, irrigation water supply showed poor management condition in 2012 with low efficiency except the Daepyong canal section, and the adequacy in 2013 was good or fair except the Yongsung canal section. When irrigation water for paddy fields was insufficient, water supply adequacy was affected by irrigation area, but when irrigation water was enough to supply, adequacy was affected by distance from main canal to distribution points. These results of the spatial and temporal dimensions of the irrigation adequacy could be utilized for efficient irrigation water management to improve the temporal uniformity and equity in the water distribution for paddy fields.

• 한국농공학회논문집
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• 제46권4호
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• pp.3-11
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• 2004

A finite volume model is developed to simulate the surface irrigation at a paddy field. The model's capabilities are validated through comparison with the simulafed results and the observed data obtained by various experimental tests, and the simulated results are in good agreement with the observed pending depth. The result of surface irrigation simulation shows that the longer the paddy field's the length of long-sided becomes, the longer the advance and storage time is taken. To analyze surface irrigation performance with variable inflow rate, three patterns of flow variation-constant rate, initially high then low, and initially low then high-were studied. The results show that at the pattern with initially high followed by low during the latter half of the irrigation the advance time is shortest, but the pending depth of irrigation completion and irrigation effiency are the little difference between irrigation patterns.

• 한국농공학회논문집
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• 제55권3호
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• pp.63-73
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• 2013

The objectives of this study were to develop a hydrologic simulation model to estimate surface drainage for irrigation districts consisting of paddy and protected cultivation, and to evaluate the applicability of the developed model. The model consists of three sub-models; agricultural supply, paddy block drainage, and protected cultivation runoff. The model simulates daily total drainage as the sum of paddy field drainage, irrigation canal drainage, and protected cultivation runoff at the outlets of the irrigation districts. The agricultural supply sub-model was formulated considering crop water requirement for growing seasons and agricultural water management loss. Agricultural supply was calculated for use as input data for the paddy block sub-model. The paddy block drainage sub-model simulates paddy field drainage based on water balance, and irrigation canal drainage as a fraction of agricultural supply. Protected cultivation runoff is calculated based on NRCS (Natural Resources Conservation Service) curve number method. The Idong reservoir irrigation district was selected for surface drainage monitoring and model verification. The parameters of model were calibrated using a trial and error technique, and validated with the measured data from the study site. The model can be a useful tool to estimate surface drainage for irrigated districts consisting of paddy and protected cultivation.

• 한국농공학회논문집
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• 제47권4호
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• pp.75-85
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• 2005

A study was performed to examine the effects of reclaimed-water irrigation on microorganism con-centration in ponded-water of paddy rice plots. Several treatments were used and each one was triplicated to evaluate the change of indicator microorganisms (total coliforms (TC), fecal coliforms FC), and E. coli) concentrations in 2003 and 2004 growing seasons. Their concentrations increased significantly right after irrigation, but decreased about $45\%$ in 24 hours. It implies that agricultural activities such as plowing and fertilizing should be practiced one or two days after irrigation considering health-risks. Treatments with UV-disinfected water irrigation demonstrated significantly lower concentrations than others including control plots where natural surface water was irrigated. The monitoring results from actual paddy rice fields and experimental paddy plots showed that concentrations of indicator microorganisms ranged from $10^2\;to\;10^5$ MPN/100mL. A comprehensive assessment of existing agricultural practices and a thorough monitoring in the field as well as treatment-plots are recommended to make more realistic national guidelines more applicable. UV-disinfected water irrigation reduced microorganism concentrations in paddy fields down to below the concentration of conventional paddy rice culture, and is thought to be an effective and feasible measure fur agricultural reuse of secondary effluent.

• 한국농공학회지
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• 제44권7호
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• pp.14-24
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• 2002

The effect of reclaimed water irrigation on paddy rice culture was evaluated by pilot study at the experimental field of Konkuk University in Seoul, Korea. The sewage was treated by constructed wetland system, and its effluent was used as irrigation water for four treatments and one control plots with three replications. Irrigation of reclaimed water onto paddy rice cultures did not adversely affect the growth and yield of rice. Instead, experimental rice plots of reclaimed water irrigation displayed about 10 to 50% more yield on average than controls. This implies that reclaimed water irrigation might be beneficial rather than harmful to rice culture as long as the sewage is treated adequately and used properly. The amount of irrigation water had little effect on experimental rice cultures, but its strength was important. The strength of treated sewage was not a limiting factor in this study, and no lodging was observed even with a relatively high nitrogen concentration (up to 160mg/L). In general the paddy soil was not affected by reclaimed water irrigation. However, there was an indication that continuous irrigation with high strength of reclaimed water might cause salt accumulation in the soil. Supplemental use of reclaimed water with existing sources of irrigation water is recommended rather than irrigation with a single source of reclaimed water. Overall, the results demonstrated that reclaimed water could be reused as a supplemental source of irrigation water for paddy rice culture without causing adverse effects as long as it is properly managed. For full-scale application, further investigation should be done on environmental risks, tolerable water quality, and fraction of supplemental irrigation.

• 한국관개배수논문집
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• 제18권1호
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• pp.94-102
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• 2011

The aim of this study was to evaluate the load of non-point sources pollutant at a paddy plot located at the valley watershed during irrigation period. Irrigation, runoff and water quality data in the paddy plot were analyzed periodically from June 1 to October 31 in 2005. The observed amount of precipitation, irrigation, runoff for the experimental paddy plot during the irrigation period was 1,297.8, 223.2, and 825.4mm, respectively. Total-N concentrations ranged from 3.73 to 18.10mg/L, which was generally higher than the quality standard of agricultural water (1.0mg/L). Total-P concentrations ranged from 0.111 to 0.243mg/L and the average was 0.139mg/L. The observed runoff pollutants loadings from the paddy plot were measured as 34.4 kg/ha for T-N, 1.0 kg/ha for T-P and 213.8 kg/ha for SS. The non-point sources pollutant load in drainage water depends on rainfall and surface drainage water amount from the paddy plot. We are considering that these results were affected by rainfall as well as hydrological condition, soil management, whether or not fertilizer application, cropping, rice straw and plowing.

• 한국농공학회지
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• 제45권4호
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• pp.55-65
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• 2003

Pilot study was conducted to examine the effects of ponded-water depth and reclaimed wastewater irrigation on paddy rice culture. For the ponded-water depth effect, three treatments of shallow, traditional, and deep water depths were applied, and each treatment was triplicated. The irrigation water for the treatment pots was an effluent from constructed wetland system for sewage treatment, while the control pot was irrigated with tap water kept traditional ponded-water depth. Irrigation water quantity varied with ponded-water depth as expected and drainage water quantity also varied similarly, which implies that shallow irrigation might save irrigation water and also reduce environmental impacts on downstream water quality. Rice growth and production were not significantly affected by ponded-water depth within the experimental condition, instead there was an indication of increased production in shallow and deep ponded-water depths compared to the traditional practice. Raising drainage outlet to the adequate height in paddy dike might be beneficial to save water resources within the paddy field. There was no adverse effect observed in reclaimed wastewater irrigation on the rice production, and mean yield was even greater than the control pots with tap water irrigation although statistically not significant. Water-saving irrigation by shallow ponded-water depth, raising the outlet height in diked rice paddy fields, minimizing forced surface drainage by well-planned irrigation, and reclaimed wastewater irrigation are suggested to save water and protect water quality. However, deviation from traditional farming practices might affect rice growth in long term, and therefore, further investigations are recommended before full scale application.