• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.145-150
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• 2020

The provision of information on the profitability and efficiency during the transition from growing rice to substitute crops is an essential task for the proliferation and settlement of the production adjustment system. First, the profitability of the soybean + barley cropping system was analyzed. The average income of the farms with the soybean + barley cropping system surveyed was 868,000 Won, with an income proportion of 55.1%. With earned income that is approximately 1.7 times higher than that of growing only rice, it is determined to be more profitable. Then, the efficiency of the farms was analyzed through DEA analysis. The efficiencies of the farms were found to include the CCR model (0.927815) and the BCC model (0.97544). It was also found that there are 10 CCR and 14 BCC results with an efficiency value of 1. With an efficiency value of more than 0.9 on average, it can be deemed as efficient management in general. In addition, by presenting a proposal for the improvement of inefficient farms, the target value was provided in order for inefficient farms to become efficient farms.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.917-926
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• 2021

Lodging rice is one of critical agro-meteorological disasters. In this study, the UAV-based multispectral imageries before and after rice lodging in rice paddy field of Jeollanamdo agricultural research and extension servicesin 2020 was analyzed. The UAV imagery on 14th Aug. includesthe paddy rice without any damage. However, 4th and 19th Sep. showed the area of rice lodging. Multispectral camera of 10 bands from 444 nm to 842 nm was used. At the area of restoration work against lodging rice, the reflectance from 531 nm to 842 nm were decreased in comparison to un-lodging rice. At the area of lodging rice, the reflectance of around 668 nm had small increases. Further, the blue and NIR (Near-Infrared) wavelength had larger. However, according to the types of lodging, the change of reflectance was different. The NDVI (Normalized Difference Vegetation Index) and NDRE (Normalized Difference Red Edge) shows dome sensitivities to lodging rice, but they were different to types of lodging. These results will be useful to make algorithm to detect the area of lodging rice using a UAV.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.958-962
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• 2006

하수처리수를 농업용수로 관개함에 있어서, 관개 유입수 및 논 담수에서의 수질은 작물이나 인체에 미치는 영향이 크다. 따라서 하수재처리수를 농업용수로 사용함에 있어서 수질 기준이 필요하게 되었으며, 이에 환경부에서 $\ulcorner$하수처리 재이용 수질 권고기준$\lrcorner$을 마련하게 되었다. 본 연구에서는 환경부에서 제시한 하수처리 재이용 수질 권고기준에 제시된 수질기준과 본 시험에 사용된 하수처리장 방류수 및 하수재 처리수의 수질을 비교하여 하수처리수의 농업용수 재이용의 적합성을 판단하였으며, 수질 모니터링을 실시하여 논에서의 수질 정화효율을 알아보았다. 본 시험을 위하여 경기도 수원시 하수처리장 인근에 시험포장을 설치하였으며, 하수처리장 방류수와 하수재처리수(여과, 소독, 저류)를 이용하여 논벼 작물 생육시험을 실시하였다. 하수처리장 방류수 수질과 하수재처리수의 수질을 분석한 결과, 수질 기준을 만족하는 것으로 나타났다. 또한, 4년간 실시된 논 유입수 및 담수의 수질 모니터링 결과 논에서의 수질 정화 효율은 TN의 경우 $40{\sim}65%$, TP의 경우 $15{\sim}60%$로 나타났다. 이는 배출수를 통한 하천이나 호소로의 유입에 있어서 환경개선효과를 기대할 수 있을 것이다. 농작업시 인체에 미치는 보건위생정도를 평가하기 위하여 지표미생물의 농도를 분석하였으며, 하수 재이용에 따른 농업용수 활용에 있어 인체에 크게 문제가 되지 않는 것으로 나타났다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.4
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• pp.114-121
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• 1997

In order to provide basic information for the estimation of evapotranspiration in the ponded direct seeding paddy field, both field lysimeter experiment and model prediction were performed to estimate daily ET. Various methods were used to predict daily reference crop ET and crop coefficients. Measure4 mean daily ET during the 1995 growing season varied from 5.9 to 6.1 mm depending on the species, while it varied from 5.1 to 5.5 mm in 1996. Model predicted mean daily ET during the 1995 growing season varied from 3.9 to 4.9 mm depending on the prediction model, while it varied from 3.5 to 4.7 mm in 1996. The smaller ET values both measured and predicted in 1996 were caused by the low values of temperature, sunshine hours, and solar radiation. Crop coefficients varied from 1.20 to 1.50 in 1995 depending on the prediction model, while it varied from 1.10 to 1.47 in 1996. Comparison of the seven reference crop ET prediction methods used in this study shows that the Penman-Monteith method and the FAO-Radiation method gave the lowest ET while the corrected Penman method and the Hargreaves method gave the largest ET. Since crop coefficients vary to a large extent based on the prediction methods, reference crop ET prediction method should be carefully selected in irrigation planning.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.3
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• pp.11-20
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• 2007

Estimation of crop consumptive use is a key term of agricultural water resource systems design and operation. The 10-year return period drought has special aspects as a reference period in design process of irrigation systems in terms of agricultural water demand analysis so that crop evapotranspiration (ETc) about the return period also has to be analyzed to assist understanding of crop water requirement of paddy rice. In this study, The ETc of 10-year return period drought was computed using frequency analysis by 54 meteorological stations. To find an optimal probability distribution, 8 types of probability distribution function were tested by three the goodness of fit tests including ${\chi}^2$(Chi-Square), K-S (Kolmogorov-Smirnov) and PPCC (Probability Plot Correlation Coefficient). Optimal probability distribution function was selected the 2-parameter Log-Normal (LN2) distribution function among 8 distribution functions. Using the two selected distribution functions, the ETc of 10-year return period drought was estimated for 54 meteorological stations and compared with prior study results suggested by other researchers.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.3
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• pp.25-35
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• 2009

Climate change due to global warming possibly effects the agricultural water use in terms of evapotranspiration. Thus, to estimate rice evapotranspiration under the climate change, future climate data including precipitation, minimum and maximum temperatures for 90 years ($2011{\sim}2100$), were forecasted using LARS-WG. Observed 30 years ($1971{\sim}2000$) climate data and climate change scenario based on SRES A2 were prepared to operate the LARS-WG model. Using these data and FAO Blaney-Criddle method, reference evapotranspiration and rice evapotranspiration were estimated for 9 different regions in South Korea and rice evapotranspiration of 10 year return period was estimated using frequency analysis. As the results of this study, rice evapotranspiration of 10 year return period increased 1.56%, 5.99% and 10.68% for each 30 years during $2011{\sim}2100$ (2025s; $2011{\sim}2040$, 2055s; $2041{\sim}2070$, 2085s; $2071{\sim}2100$) demonstrating that the increased temperature from the climate change increases the consumptive use of crops and agricultural water use.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.3
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• pp.66-75
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• 2000

Effect of reclaimed sewage on the paddy rice culture was examined by field experiment for two consecutive years. The domestic sewage was treated by the constructed wetland and the effluent of the treatment wetland was used for irrigation water. The reclaimed sewage was diluted before irrigation in the first year and it was used without dilution in the second year experiment. Growth components and yields were compared against the control plot where conventional method was applied. And also soil characteristics of the plots before and after reclaimed sewage irrigation were analyzed Generally addition of the reclaimed sewage irrigation didn't affect paddy rice culture adversely and even enhancement was observed. Fertilization was thought to be important factor for rice culture rather than irrigation water quality. Conventional fertilization and reclaimed sewage irrigation which contained high nutrient concentration resulted in better growth and more yield. Unlike widespread concern lodging did not happen even in the case of irrigation with average 90mg/L of T-N and conventional fertilization. Soil characteristics changed after irrigation and significant EC increasing was observed for the reclaimed sewage irrigation plots. From soil analyses salt accumulation could be a more potential problem than nutrients like nitrogen and phosphorus in the use of reclaimed sewage irrigation. Overall reclaimed sewage irrigation was thought to be one of practical alternatives for the ultimate disposal of sewage in rural area.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1883-1886
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• 2010

농업가뭄은 강수의 부족으로 인하여 농업용 저수지의 저수량 저하로 농작물 생육 및 수확량의 직접적인 영향을 미치는 것으로, 농업가뭄평가는 강수량뿐만 아니라 작물의 생육시기별 필요수량과 용수공급능력을 모두 고려할 수 있어야 한다. 농업가뭄관리의 주요 대상인 논벼는 기본적으로 수원공과 관개지역 사이의 물수지를 판단함으로써 농업가뭄의 위험을 정의할 수 있다. 본 연구에서는 가뭄관리가 필요한 농업용 저수지 관개지구의 농업가뭄 평가를 위해 논 물수지 분석 모형과 저수지 물수지 분석 모형을 구성하고, 용수수급해석의 결과로부터 가뭄의 크기를 객관화하고 가뭄의 단계를 평가할 수 있도록 빈도개념을 적용한 저수지가뭄지수 (Reservoir Drought Index, RDI)를 이용하여 농업가뭄을 분석 평가하였다. 또한 농업용 저수지의 저수량 모의치와 실시간 저수위를 이용하여 경험적으로 농업용 저수지의 유입량을 자동으로 보정하여 장기적으로 최적화할 수 있는 방안을 제시하였으며, 과거 유효강수량을 시기별로 나누어 빈도분석을 통해 농업가뭄대응을 위한 가뭄 기상시나리오를 사용하여 향후 가뭄의 여러 가지 패턴에 따른 농업가뭄을 전망하였다. 이러한 다양한 시나리오를 통해 실제 물 관리 및 가뭄대책 업무에 반영하고 농업가뭄대응책 수립 및 농업수자원관리의 의사결정을 수립하는데 기초자료가 될 것으로 판단된다.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.3
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• pp.141-148
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• 2012

Food policy is considered as the most basic and central issue for all countries, while making efforts to keep each country's food sovereignty and enhance food self-sufficiency. In the case of Korea where the staple food is rice, the rice yield prediction is regarded as a very important task to cope with unstable food supply at a national level. In this study, Korean paddy Rice yield Prediction Model (KRPM) developed to predict the paddy rice yield using meteorological element and MODIS NDVI. A multiple linear regression analysis was carried out by using the NDVI extracted from satellite image. Six meteorological elements include average temperature; maximum temperature; minimum temperature; rainfall; accumulated rainfall and duration of sunshine. Concerning the evaluation for the applicability of the KRPM, the accuracy assessment was carried out through correlation analysis between predicted and provided data by the National Statistical Office of paddy rice yield in 2011. The 2011 predicted yield of paddy rice by KRPM was 505 kg/10a at whole country level and 487 kg/10a by agroclimatic zones using stepwise regression while the predicted value by KOrea Statistical Information Service was 532 kg/10a. The characteristics of changes in paddy rice yield according to NDVI and other meteorological elements were well reflected by the KRPM.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.5
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• pp.35-41
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• 2012

The paddy rice consumptive use in the six plains of the Korean peninsula was projected with changing climate under the representative concentration pathway (RCP) scenarios. High resolution climate data for the baseline (1961-1990) was obtained from the International water management institute (IWMI) and future high resolution climate projection was obtained from the Korea Meteorological Administration. Reference evapotranspiration (ET) was calculated by using Hargreaves equation. The results of this study showed that the average annual mean temperature would increase persistently in the future. Temperatures were projected to increase more in RCP8.5 than those in RCP4.5 scenario. The rice consumptive use during the growing period was projected to increase slightly in the 2020s and then more significantly in the 2050s and 2080s. It showed higher values for RCP8.5 than for RCP4.5. The rice consumptive use after transplanting in the study areas would increase by 2.2 %, 5.1 % and 7.2 % for RCP4.5 and 3.0 %, 7.6 %, and 13.3 % for RCP8.5, in the 2020s, 2050s, and 2080s, respectively, from the baseline value of 534 mm. The results demonstrated the effects of climate change on rice consumptive use quite well, and can be used in the future agricultural water planning in the Korean peninsula.