Comparison of Several Methods for Calculation of Reference Evapotranspiration

Rácz, Csaba; Nagy, János; Dobos, Attila

doi:10.2478/aslh-2013-0001

Cited by 27 publications

(24 citation statements)

References 18 publications

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“…Therefore, the maximum, minimum, mean, lower and upper quartile of the long term daily reference evaporation for the period are shown in Rácz et al [15] stated that methods having smallest RMSE have the lowest systematic error in predicting ET 0 . …”

Section: Reference Evaporation: Comparing the Methodsmentioning

confidence: 99%

“…Agronomists and hydrologists have little guidance [15] [26] to choose among the many available methods to estimate reference evaporation in the Ethiopian highlands where the density of weather station is low [27] [28] and often only measure temperature and precipitation. The objective of this study is, therefore, to select the most accurate method for estimating reference evaporation for the Ethiopian highlands.…”

Section: A a Adem Et Al Journal Of Water Resource And Protectionmentioning

confidence: 99%

“…In the literature, these validation methods are divided in four categories. The first category uses the evaporation measured with Class A pan [15] [16] [17]. Other studies employ the ET 0 of FAO-Penman Monteith for validation [7] [10] [11] [18] [19] [20] [21].…”

Section: Introductionmentioning

confidence: 99%

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Predicting Reference Evaporation for the Ethiopian Highlands

Adem¹,

Aynalem²,

Tilahun³

et al. 2017

JWARP

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Water is likely the most limiting factor in increasing agricultural production in large parts of Africa. Reference evaporation (ET 0 ) is a key hydrological parameter to use efficiently the scarce supply. Several methods are available for predicting reference evaporation, but the accuracy of any of the methods has not been established for the Ethiopian highlands. The objective of this study is, therefore, to select the best methods for calculating the reference evaporation ET 0 . For the section, meteorological data of the Bahir Dar station were used, because all data needed for this study including the Class A pan Evaporation were recorded on a daily basis. Pan evaporation was considered as the best estimator of the reference evaporation. The results showed that the FAOPenman Monteith (using solar radiation, wind speed, temperature and relative humidity) and Enku method (using only maximum daily temperatures) have acceptable daily ET 0 ranges and predicted to Class A pan evaporation with correlation coefficients greater than 90% in a monthly basis. Next best was the Thornthwaite's method with correlation coefficient of 89% with pan evaporation. Piche methods performed relatively well with correlation coefficient of greater than 70%. Blaney-Criddle, Priestley & Taylor, and Hargreaves performed the poorest in predicting pan evaporation. These methods should be recalibrated for local condition and therefore not recommended for use in the Ethiopian highlands. In summary, the FAO-Penman Monteith is recommended for locations where the input data are available; otherwise, the Enku method using maximum daily temperature is best for estimating the reference evaporation.

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Section: Reference Evaporation: Comparing the Methodsmentioning

confidence: 99%

Section: A a Adem Et Al Journal Of Water Resource And Protectionmentioning

confidence: 99%

See 1 more Smart Citation

Predicting Reference Evaporation for the Ethiopian Highlands

Adem¹,

Aynalem²,

Tilahun³

et al. 2017

JWARP

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“…The comparison between local Kc and the existent FAO values is always performed to ensure the quality of the new values (Araujo et al, 2011;Cavalcante Jr et al, 2011;Rácz et al, 2013;Filho et al, 2015;Kisi, 2016). A study developed in Texas (USA) found coefficient of Pearson of 0.87 for the new values of Kc for wheat as compared to the FAO value (Ko et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Determination of wheat crop coefficient (Kc) and soil water evaporation (Ke) in Maringa, PR, Brazil

Paulo¹,

Paulo²,

Andre³

et al. 2016

Afr. J. Agric. Res.

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The objective of the present study was to determine the crop coefficient (Kc) of wheat and soil water evaporation (Ke) in Maringá, PR, Brazil. Wheat crop evapotranspiration (ETc) was determined through the water balance method, using drainage lysimeters integrated with soil moisture measurements. The ETo was calculated using the Penman-Monteith equation with climate data from an automatic weather station, then Kc was calculated. Microlysimeters were built, using PVC pipes with 100 mm diameter and 150 mm length, which were weighted every day to obtain the quantity of water evaporated and then the soil water evaporation coefficient (

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“…Values of KC varies over the crop growth stages and increases from a minimum value at sowing until a maximum KC reaches full canopy cover, the KC tends to decline at a point after a full cover is reached in the crop season [ALLEN et al 2006;KO et al 2009]. The comparison between local KC and the existent FAO values is always performed to ensure the quality of the new values [ARAUJO et al 2011;CAVA-LCANTE et al 2011;FILHO et al 2015;KISI 2016;RÁCZ et al 2013] Overall, estimation of crop coefficient in the regions of salt affected soils can assist to improve the agricultural management. In this respect, a field experiment was conducted for determination of water stress coefficient (Ks) and KC for wheat under different salinity in the semi-arid environment.…”

Section: Introductionmentioning

confidence: 99%

Wheat water use and yield under different salinity of irrigation water

Abedinpour

2017

Journal of Water and Land Development

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A field experiment was conducted for determination of crop coefficient (KC) and water stress coefficient (Ks) for wheat crop under different salinity levels, during 2015-2016. Complete randomized block design of five treatments were considered, i.e., 0.51 dS·m -1 (fresh water, FW) as a control treatment and other four saline water treatments (4, 6, 8 and 10 dS·m -1 ), for S 1 , S 2 , S 3 and S 4 with three replications. The results revealed that the water consumed by plants during the different crop growth stages follows the order of FW > S 1 > S 2 > S 3 > S 4 salinity levels. According to the obtained results, the calculated values of KC significantly differed from values released by FAO paper No 56 for the crops. The Ks values clearly differ from one stage to another because the salt accumulation in the root zone causes to reduction of total soil water potential (Ψ t ), therefore, the average values of water stress coefficient (Ks) follows this order; FW(1.0) = S 1 (1.0) > S 2 (1.0) > S 3 (0.93) > S 4 (0.82). Precise data of crop coefficient, which is required for regional scale irrigation management is lacking in developing countries. Thus, the estimated values of crop coefficient under different variables are essential to achieve the best management practice (BMP) in agriculture.

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Comparison of Several Methods for Calculation of Reference Evapotranspiration

Cited by 27 publications

References 18 publications

Predicting Reference Evaporation for the Ethiopian Highlands

Predicting Reference Evaporation for the Ethiopian Highlands

Determination of wheat crop coefficient (Kc) and soil water evaporation (Ke) in Maringa, PR, Brazil

Wheat water use and yield under different salinity of irrigation water

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