• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.1
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• pp.1598-1603
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• 1969

A field expeperiment has been conducted in order to explore possibilities of efficient and economical irrigation methods for the rice cultivation through which irrigation water may be saved and rice paddies may keep water for longer period of time, resulting in an increased yield of rice. Some of the major findings from the experimentation are summarized in the following. 1. There is slightly significant difference among experimental plots in the weight of rice straw. 2. The 9cm-lined plot proves to be the best in terms of the thickness. In this connection, however, it seems to by 3cm. 3. The wheat straw-lined plot is found superior in yield. However, this may be resulted in by the application of more fertilizer, and how long the plot could be durable may be problematic. Since every two or three years the straw-lining work has to be done, more labour may be required of the plot. 4. It would be inappropriate to expect any meaningful experimental results for the first year, since surface soil and deep soil are mixed up in the course of work. There is not observed any meaningful difference in the number of ears per stalk and in the number of grains per ear. However, in the lined plots, the number of tillers is slightly increased. 5. Irrigation has been applied by means of ordinary method after lining. When irrigation is applied at the interval of five to six days, irrigation water is saved by 44.9 per cent in the case of 9cm-lined plot, 39.7 per cent in the case of 6 cm-lined plot, and 36.3 percent in the case of 3 cm-lined plot. 6. An increased yields arenoted in the wheat straw-lined plot by 23.8 per cent, in the 9 cm-lined plot by 20.1 per cent, in the 3 cm-lined plot by 12 per cent. and in the case of vinyl-lined plot by 12.5 per cent. 7. The rate of maturity of grains is proved better, and the husking rate also found better(75%), that is, the quality of rice grains is improved.

• Korean Journal of Environmental Agriculture
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• v.39 no.1
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• pp.36-43
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• 2020

BACKGROUND: Wicheon watershed has the largest irrigation area among the mid-watershed of Nakdong river. However, no investigation of irrigation water quality has been conducted on the Wicheon watershed, which evaluates the effects on the soil quality and crop cultivation. Therefore, this study aims to provide various assessments of water quality of Wicheon watershed as the scientific basic data for efficient agricultural activities. METHODS AND RESULTS: Water sampling was performed in five locations of the first tributaries of Wicheon. Wicheon watershed showed clean water quality with very low organic matters and safe water quality from metals at all points of investigation. It was estimated that the natural chemical components of Wicheon watershed were originated from water-rock interaction in Gibbs diagram. All samples were concentrated in the type of Ca-HCO₃-Cl in the Piper diagram. The quality of irrigation water was evaluated with sodium adsorption ratio (SAR), residual sodium carbonate (RSC), permeability index (PI), and percent sodium (%Na). The values of these water quality indices were in the range of 0.37-0.67, -2.11--0.24, 41.13-84.52% and 11.28-21.84%, respectively, and were classified as good grades at all sites. CONCLUSION: The water quality of Wicheon watershed was very low in salt, indicating good irrigation water suitable for growing agricultural products. We hope that the results of this study will be used as the basic data for the cultivation of agricultural products and promotion of their excellence.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.221-225
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• 2002

This study was conducted to identify the effects of slow release fertilizer (LCU) on ridge direct seeding on dry paddy of rice as an irrigation water-saying cultural system. During 1999-2000, a series of experiments was carried out at field (Chonbuk series) of the National Honam Agricultural Experiment Station, RDA using Dongjinbyeo. Plant height and culm length during the total growth duration were the longest and panicle umber per $m^2$ was the highest in 100% LCU application rate. Leaf area index and top dry weight were the highest in the 100% LCU application rate. They increased as more LCU was applied. Nitrogen uptake was the highest in 100% LCU application, and N use efficiency was the highest in LCU 60% + FP (fertilization at panicle formation stage) 20% application. Milled rice yield was 7% higher in 100% LCU application rate than that of conventional N application. Ripened grain rate and 1,000-grain weight of brown rice did not differ, but panicle number per $m^2$ and grain number per m2 were the highest at 100% LCU application.

• Journal of Korea Water Resources Association
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• v.46 no.10
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• pp.1005-1016
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• 2013

The objective of this study was to evaluate spatio-temporal water shortage distribution in the Sapgyo catchment considering both permitted and non-permitted water rights obtained from the total water right survey conducted in 2010. The results showed that the agricultural water accounted for 98% of the total water uses with 83% being the non-permitted agricultural water uses. During the 11-year (2001~2011) simulation period, water shortage was shown only in the upper Gokgyo stream sub-catchment with the highest water stress from April to May in 2009, particularly because of the large demand for rice cultivation associated with low precipitation. As water shortage was not expected to happen when the permitted water rights were not considered, it was concluded that a proper management of non-permitted water rights would be urgent.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.171-175
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• 1996

Seed occurrence patterns of Echinochloa crus-galli (L) P. Beauv. and Monochoria vaginalis (Burm. f.) Presl. were investigated in irrigated and rainfed rice cultures. There was not much difference in seed population of E. crus-galli between irrigated and rainfed fields, but M. vaginalis occurred in about 1.6-fold greater number in rainfed fields. In seed distribution patterns under the two conditions, about 50% and 30% of E. crus-galli and M. vaginalis, respectively, were found in the uppermost 5cm layer. Under both conditions M. vaginalis was distributed to a depth of 25cm, but distribution of E. crus-galli was only 15cm deep. Early rice transplanting brought about greater emergence of the two weeds than optimal or late transplanting. Emergence of the weeds was significantly greater in single cropping system of rice than in double cropping systems of rice followed by barley and/or strawberry.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.235-235
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• 2017

수문 순환과 물 수지에 관한 연구는 강수량, 지표유출량, 지하수, 토양수분 및 증발산량 등에 대한 관측이 이루어질 때 실제로 규명될 수 있다. 하지만, 수문 순환과 물수지 평가에 중요한 부분을 차지하는 증발산량의 경우 관측값보다 단순한 가정이나 경험식에 의한 추정값을 사용하고 있다. 따라서, 수문 순환과 물수지의 정량적인 분석을 위해서는 수문 순환 과정에서 상당부분을 차지하는 증발산량의 측정(실측)과 자료의 축척이 필요한 실정이다. 본 연구는 국토교통부의 기초수문자료 구축사업의 일환으로 수행되었으며, 수문자료의 다양화 목적을 가지고 에디공분산 기술을 사용하여 증발산량을 직접 관측하고 있다. 관측지점은 한반도의 약 70%를 차지하는 산림지 중 대표적 식생 기능 형태인 혼효림으로 구성된 지점(설마천 관측소, 2007년 8월부터)과, 인위적인 관개가 이루어지는 농경지(청미천 관측소, 2008년 8월부터)에서의 증발산량 측정을 수행하였다. 관측된 자료를 활용하여 관측소별로 연도별 증발산량 특성을 분석한 결과는 다음과 같다. 설마천 관측소(주변식생 : 혼효림)에서 산정된 연증발산량은 2008년 471.7mm, 2009년 408.4mm, 2010년 489.4mm, 2011년 387.0mm, 2012년 323.3mm, 2013년 293.3mm, 2014년 360.9mm, 2015년 419.6mm, 2016년 566.9mm이고, 발생한 강수량 대비 증발산 비율은 18.9%~56.2%범위로 산정되었다. 청미천 관측소(주변식생 : 농경지)에서 산정된 연증발산량은 2009년 571.8mm, 2010년 650.6mm, 2011년 523.9mm, 2012년 509.8mm, 2013년 467.9mm 2014년 533.9mm, 2015년 600.5mm, 2016년 588.0mm이고, 발생한 강수량 대비 증발산량의 비율은 25.6%~71.4%범위로 산정되었다. 강수량 대비 증발산량 비율의 최대값은 설마천 관측소는 2014년, 청미천 관측소는 2015년에 발생하였다. 평균 증발산량 비율은 산림지인 설마천 관측소보다 논경지인 청미천 관측소가 평균 13.3%정도 높은 특성을 보였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.332-332
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• 2023

농업용 저수지는 농촌유역의 홍수조절에 핵심적인 역할을 하지만 기본적인 기능은 이수 기능이기 때문에 농업용수 수량을 충분하게 확보하면서 동시에 홍수에도 대비할 수 있도록 저수지를 적절히 운영하는 것이 중요하다. 이에 농업용 저수지마다 홍수기 제한수위를 설정하여 홍수조절용량과 농업용수를 적절하게 확보하도록 하고 있으나, 현재 홍수기 제한수위는 저수지별 특성을 고려하지 않고 70% 정도의 저수율 기준이 일괄적으로 적용된 경우가 대부분이며 시기별 농업용수공급 특성을 고려하지 못한다. 이에 본 연구에서는 농업용 저수지의 이수안전도 및 치수안전도를 이용하여 이·치수 기능을 모두 고려한 홍수기 제한수위 설정 방안을 제시하였다. 홍수기 제한수위는 초기 (6/21~7/20), 중기 (7/21~8/20), 후기 (8/21~9/20)에 대해 각각 설정하였고, 오봉저수지와 묘곡저수지에 대해 1973~2022년의 기상자료를 이용하여 이·치수를 모의하였다. 관개기 최저저수량 및 이듬해 4월의 저수량을 기준으로 이수안전도를 산정하고, 재현기간 100년/200년/500년 홍수에 대해 저수지 운영을 모의하여 최고저수량을 기준으로 치수안전도를 산정하였다. 초기/중기/후기 제한수위 조합에 대한 이수안전도 및 치수안전도 값을 좌표공간에 점으로 도시하고 Pareto front를 도시하여 최적의 제한수위 범위를 도출하였다. 분석 결과, 오봉저수지의 이수안전도는 후기 제한수위에 의해 대부분 결정되며, 초기/중기 제한수위는 큰 영향을 주지 못하는 것으로 나타났다. 반면 묘곡저수지의 이수안전도는 초기 제한수위에 의해 크게 영향을 받으며, 그 영향이 이듬해까지 이어지는 것으로 나타났다. 이를 토대로 최적의 제한수위를 도출한 결과, 오봉저수지의 경우 초기 65%, 중기 65~80%, 후기 95% (유효저수량에 대한 비율)로 시기별 수문 운영이 필요한 것으로 나타났고, 묘곡저수지의 경우 초기 100%, 중기 95%, 후기 65~80%로 취수 구조물 또는 비상수문 설치를 통한 방류가 필요한 것으로 나타났다. 본 연구에서 제시한 방법을 통해 저수지별 특성을 고려하여 홍수기 제한수위를 설정함으로써 효율적인 저수지 운영이 가능할 것으로 기대된다.

• Korean Journal of Environmental Agriculture
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• v.27 no.2
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• pp.111-119
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• 2008

This study was conducted to evaluate water quality and pollutant loads on small agricultural watershed in Jeonbuk province. The EC level of investigated watershed ranged from 0.07 to 0.52 dS/m, BOD level ranged from 0.1 to 5.0 mg/L, and $COD_{Cr}$ level ranged from 0.6 to 17.7 mg/L. As above, contents of water quality indicators covered wide range, but each indicator was alike in mean content every other year. The contents of EC, $Ca^{2+},\;Mg^{2+},\;K^+\;and\;Na^+$ were decreased in rainy season, but the contents of BOD, $COD_{Cr},\;COD_{Mn}$, T-N and T-P were not greatly different as compared to dry season. And high content of SS showed substantial sediments near the surface flow out and influence on water system in rainy season. The pollutant loads measured in terminal of watershed were $9.6{\sim}757.9$ kg/day for BOD, $51.2{\sim}1418.5$ kg/day for T-N and $0.3{\sim}44.7$ kg/day for T-P. The pollutant loads of BOD, T-N and T-P in rainy season increased several times as compared to dry season. In rainy season, watershed with more than 30% in the proportion of paddy field to land showed relatively low discharge and pollutant loads in comparison to watershed with less than 30%. The discharge of watershed in rainy season increased 5.7times compared with the dry season in watershed with less than 30% in the proportion of paddy field to land, whereas was only 2.3times in watershed with more than 30%. The correlation coefficient($R^2$) of regression between discharge and pollutant loads of T-N were higher than those of BOD and T-P.

• Korean Journal of Environmental Agriculture
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• v.24 no.1
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• pp.24-28
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• 2005

Waste of the hydroponic solution from the plastic film house cultivation was recycled to grow the red pepper(Capsicum annum L.) in upland fields as supplement for plant nutrients and irrigation sources. Application of hydroponic waste solution increased the pH and EC of the soils, coupled with the increases in the concentrations of exchangeable cations(Ca, Mg, and K), total nitrogen, $NH_4-N,\;and\;NO_3-N$. Growth and yield of red pepper were highest when the treatment of chemical fertilizer(70%) was combined with hydroponic waste solution(30%). Amounts of the daily producing hydroponic waste solution were 2,880 L $ha^{-1}\;day^{-1}$ from the experimental facilities and this could irrigate $409.86m^2$ of area to compensate for the amount of water loss by evapotranspiration(3%). The overall results demonstrated that hydroponic waste solution could be recycled as plant nutrients and irrigation water resources for enhancing soil fertility and environmental quality.

• Korean Journal of Agricultural Science
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• v.36 no.1
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• pp.99-109
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• 2009

This study was performed to evaluate the effect of increasing instream flow at Nonsancheon stream of Nonsan city by securing water storages in upstream reservoirs; Ge-ryong, Gyoung-cheon, Dae-dun, and Tab-jeong. The paralleled and cascaded upstream reservoir operations for 8 storage securing scenarios were considered to simulate daily streamflows at Nonsan station. Using Tab-jeong reservoir water storage, the DAWAST model's parameters were determined, and the verified result showed Nash-Schcliffe's coefficient of 0.666. Instream flows were analyzed to supply maximum $59.85Mm^3$ on an annually average from upstream reservoir storage securing scenarios. The storage securing set of 2 m heightened Ge-ryong, 5 m Dae-dun, and 1 m Tab-jeong showed that the additional secured water storages were $17.132Mm^3$ and instream flow at Nonsan station was increased to $2.183m^3/s$, 2 times of present condition.