NEW METHODOLOGY FOR ESTIMATING EVAPOTRANSPIRATION AND UPDATING CROP COEFFICIENT FOR RICE IN EGYPT BY SURFACE RENEWAL METHOD | ||||
Misr Journal of Agricultural Engineering | ||||
Article 3, Volume 36, Issue 4, October 2019, Page 1075-1088 PDF (748.09 K) | ||||
Document Type: Original Article | ||||
DOI: 10.21608/mjae.2019.94875 | ||||
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Authors | ||||
A. Abo El-Magd1; S. M. Attaher1; R. L. Snyder2; H. S. Mehawed1; G. H. El-Sayed1 | ||||
1Agric. Eng. Res. Inst. (AEnRI), Agric. Res. Center (ARC), Dokki, Giza, Egypt. | ||||
2Land Air Water Resources Dept., Univ. of California, Davis, USA. | ||||
Abstract | ||||
Improving irrigation management needs accurate information and tools to estimate accurate crop-water requirements. At the national level, one of the biggest deficiencies in water-use planning is a lack of continues and updated data sets of evapotranspiration and accurate crop coefficient values. The aim of this study is to evaluate locally, the “Surface Renewal (SR)” method, as an energy balance direct method to estimate crop evapotranspiration (ETc), and upgrade crop coefficients (Kc) of rice crop in Egypt. SR station was installed in the “agricultural production sector” farm in Moshtouhor, at Kaliobia governorate, in order to collect high resolution field observations of energy balance factors of paddy rice field. The data was used to calculate the actual crop evapotranspiration (ETc) and crop coefficient(Kc) of the crop by using the SR method, and comparing the result with the standard values recommended by FAO. The overall RMSE between the ETc-SR and the ETc-FAO was 0.92 mm/day. The error was at the highest level at the initial-season stage, and slightly decreased to reach to 0.48 mm/day by the end of the season. The average value of Kc-SR was 1.17, 1.13 and 1.14 at the initial-season, mid-season and late season stages, respectively. The RMSE between the Kc-SR and the Kc-FAO values were 0.17, 0.10 and 0.03 at the initial-season, the mid-season, and the late-season stages, respectively. The combination of the SR procedure and the simplified surface energy balance equation appears being an affordable alternative to be considered for estimating water use in agriculture. In the other hand, the SR method still need several evaluations, calibration work, in order to be used significantly to upgrade the Kc value for the local crop cultivars in Egypt. | ||||
Keywords | ||||
Energy balance; water requirements; on-farm irrigation management | ||||
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