• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.20-25
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• 2005

In 1998, Food and Agriculture Organization addressed that FAO Modified Penman method possibly overestimates consumptive use of water comparing to the measured reference crop evapotranspiration (PET) and Penman-Monteith method can be better choice for accurate PET estimation. Nevertheless it is still difficult to find research efforts about paddy rice crop coefficient for Penman-Monteith method. This study aims to estimate paddy rice crop coefficients for Penman-Monteith method. To estimate the crop coefficients, measured evapotranspiration data during 1982-1986 were used. The average Penman-Monteith crop coefficients for transplanted paddy rice were ranged in $0.78\;{\sim}\;1.58$.

• 한국농공학회지
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• 제40권1호
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• pp.43-48
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• 1998

In order to provide basic information for the estimation of evapotranspiration for grass (Joycia Japonica), 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. Measured mean daily ET during the 1997 growing season was 4.5mm Model predicted mean daily ET during the 1997 growing season varied from 3.6 to 4.7mm depending on the prediction model Crop coefficients varied from 0.96 to 1.27 depending on the prediction model Comparison of the seven reference crop ET prediction methods used in this study shows that the Penman-Monteith method gave the smallest ET while the Hargreaves method gave the largest ET. The crop coefficient by the corrected Penman method was 1.03, which is closest to 1.0, suggesting that this method may he the best prediction method.

• 한국관개배수논문집
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• 제6권2호
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• pp.37-46
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• 1999

This study is performed to select irrigation design year from 10-year return period 7-month(April to October) precipitation and compare reference crop evapotranspiration at 13 stations by REF-ET model. The three smallest 10-year return period 7-month(Apri

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.271-274
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• 2003

The objectives of this study are for finding an optimal calculation method comparing observed evapotranspiration with calculated evapotranspiration by Blaney-Criddle, Penman and Penman-Monteith method which are used in many place of Korea. And after appling optimal calculation method, optimal irrigation is presented through calculation of effective rainfall and requirement water considering characteristics of region, crop and soil.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.126-126
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• 2022

Climate change has continued to impact meteorological factors like rainfall in many countries including Nigeria. Thus, altering the rainfall patterns which subsequently affect the crop yield. Maize is an important cereal grown in northern Nigeria, along with sorghum, rice, and millet. Due to the challenge of water scarcity during the dry season, it has become critical to design appropriate strategies for planning, developing, and management of the limited available water resources to increase the maize yield. This study, therefore, determines the quantity of water required to produce maize from planting to harvesting and the impact of drought on maize during different growth stages in the region. Rainfall data from six rain gauge stations for a period of 36 years (1979-2014) was considered for the analysis. The standardized precipitation and evapotranspiration index (SPEI) is used to evaluate the severity of drought. Using the CROPWAT model, the evapotranspiration was calculated using the Penman-Monteith method, while the crop water requirements (CWRs) and irrigation scheduling for the maize crop was also determined. Irrigation was considered for 100% of critical soil moisture loss. At different phases of maize crop growth, the model predicted daily and monthly crop water requirements. The crop water requirement was found to be 319.0 mm and the irrigation requirement was 15.5 mm. The CROPWAT 8.0 model adequately estimated the yield reduction caused by water stress and climatic impacts, which makes this model appropriate for determining the crop water requirements, irrigation planning, and management.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.275-278
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• 2003

The crop coefficient of rice were investigated using the Penman-Monteith method in Cheongju, in central South Korea. The mean actual evapotranspiration of rice was 4.8 mm/d, and highest evapotranspiration of rice was 6.6 mm/d in late August in 2001. The crop coefficient of rice showed 1.0 in early irrigation season, but over 1.5 in late irrigation season. The mean crop coefficient of rice in central area(1.16) was lower than that in southern area(1.49)

• 한국농공학회논문집
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• 제61권2호
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• pp.97-104
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• 2019

The purpose of this study was to establish the estimation method of irrigation water amount for sewage treated water reuse for agricultural purpose. To calculate the irrigation water amount, we adopted Penman-Monteith for potential evapotranspiration estimation and applied crop coefficient and irrigation efficiency factor. We developed the irrigation water amount calculation program using C language in Xcode environment. The target district for calculation is having 259 ha of agricultural land located near the Jinyeong Clear Water Circulation Center in Hanrim-myeon, Gimhae city. The meteorological data of the study area were obtained from Changwon weather station from 1986 to 2017. Calculated average and maximum of annual mean potential evapotranspiration were 2.72 mm/day and 6.22 mm/day, respectively. We used K-S (Kolmogorov-Smirnov) for goodness-of-fit test to find optimal probability distribution of annual mean and maximum evapotranspiration. As a result, the normal distribution was selected for the appropriate distribution. The annual mean and maximum potential evapotranspiration for 10-year return period by applying normal distribution were 2.88 mm/day and 6.76 mm/day, respectively. Assuming that the irrigation efficiency is 80%, the irrigation water requirement was calculated as $36.05m^3/day/ha$ and $84.45m^3/day/ha$, respectively, when annual mean and maximum potential evapotranspiration were applied. The actual irrigation water amount can be calculated by applying the crop coefficient and cropping days for the study area based on the developed irrigation water amount estimation program in this study.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1989년도 하계 학술대회지
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• pp.30-31
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• 1989

• 한국농림기상학회:학술대회논문집
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• 한국농림기상학회 2011년도 학술발표회
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• pp.7-10
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• 2011

The semi-arid and arid regions comprise almost 40 percent of the world's land surface. The low and erratic precipitation pattern is the single most significant contributor for limiting crop production in such regions where rainfall is the source for surface, soil and ground water. In a changing climate, the semi-arid and arid regions would increasingly face the challenge of water scarcity. According to the relevant literature; under the assumption of a doubling of the current atmospheric CO2 concentration, irrigation demand was estimated to increase for wheat and to decrease for second crop maize in a Mediterranean environment of Turkey in the 2070s. Crop evapotranspiration would decrease due to stomata closure. Reference evapotranspiration and potential soil evaporation were projected to increase by 8.0 and 7.3%, respectively, whereas actual soil evaporation was predicted to decrease by 16.5%. Drainage losses below 90 cm soil depth were found to decrease mainly due to lesser rainfall amount in the future.

• 한국농공학회지
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• 제39권4호
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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.