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Sara bulukazari; Hossein Babazadeh; Nyazali Ebrahimipak; Seyed Habib Mousavi-Jahromi; Hadi Ramezani_etedali
Abstract
In exploitation of low-quality water in arid and semi-arid regions, irrigation management is essential to increase water use efficiency. Determination of crop-water-salinity production function is an essential tool for proper irrigation management. In this study, the AquaCrop model was first evaluated ...
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In exploitation of low-quality water in arid and semi-arid regions, irrigation management is essential to increase water use efficiency. Determination of crop-water-salinity production function is an essential tool for proper irrigation management. In this study, the AquaCrop model was first evaluated by considering 4 soil and water salinity levels and 4 deficit irrigation levels for the major cereal crops including wheat, barley, and corn in Qazvin Plain. The results showed that the coefficients of determination for wheat, barley, and corn yield were 0.97, 0.86 and 0.91, respectively. Therefore, the model can evaluate the performance in salinity and deficit irrigation conditions with a good approximation. To determine the optimal production functions of each crop, the results of the plant model were compared with three models of linear and nonlinear regression, and artificial neural network. The neural network model was able to estimate the performance compared to the AquaCrop model with lower error and higher correlation (0.99). These values in the linear function for wheat, barley, and corn were 0.98, 0.95, and 0.78 and in the nonlinear function as 0.92, 0.86 and 0.81, respectively. Also, the error calculated in the neural network method for wheat, barley, and maize was 40.16, 62.09, and 57.08 kg, respectively, which were less than the linear model by 75 %, 70 %, and 95 %; and less than the exponential model by 90 %, 85 %, and 93%, respectively. The best trained network for determining the water-salt production function for barley and wheat 5 Nero and for corn 7 Nero was introduced in the single layer structure. Sensitivity analysis on wheat and barley showed that this model had low sensitivity to irrigation and salinity parameters and only corn plant showed a moderate range sensitivity to salinity parameter.
Khadijeh Barati; Jahangir Abedikoupaee; Elham Darvishi; Arash Azari; Ali Yousefi
Abstract
To prepare the National Water Document of the country, a 25-year statistical period of 1970-1995 has been used to calculate daily potential evapotranspiration. Due to the climate changes that have taken place in recent years, updating this national valuable work is necessary. Since so far there has been ...
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To prepare the National Water Document of the country, a 25-year statistical period of 1970-1995 has been used to calculate daily potential evapotranspiration. Due to the climate changes that have taken place in recent years, updating this national valuable work is necessary. Since so far there has been no study on determining the changes in irrigation requirement of plants of cropping pattern in Kermanshah plain in the current climate conditions compared to the values presented in NETWAT software, this subject was investigated. In this study, to calculate crops water requirement, the meteorological data of 2006-2007 to 2015-2016 were used. In order to estimate the net irrigation requirement for cropping pattern in Kermanshah plain, ET0 calculator software was used to calculate evapotranspiration of reference crop. Then, the evapotranspiration values of the cropping pattern, the effective rainfall and, eventually, the amount of net irrigation requirement of the crops were calculated. The comparison between the values obtained in this research with available values in NETWAT software indicate that, for most plants, the obtained values in this study are on average 1.2 times the amounts presented in the NETWAT software. This ratio is about 2 for wheat and barley and about 1 for clover, cantaloupe, pea, and almond. The results of lysimeteric researches in the study area confirms the correctness of the performed calculations in this study.