Ayman Hejazi*(1) Rabiaa Alhayek(2) and Mohammad Hakkoun(1)
(1). Natural Recourses Research Administration, General Commission for Scientific Agricultural Research (GCSAR), Damascus, Syria.
(2). Agricultural Research Center of Salamya, (GCSAR), Hama, Syria.
(*Corresponding author: Eng: Ayman Hejazi. E-Mail: siraiman@yahoo.com).
Received: 30/06/ 2015 Accepted: 07/09/ 2015
Abstract
This theoretical study was carried out in 2014 to study CropWat 8 model suitability to estimate water requirements and irrigation scheduling for some fruit trees and crops, using field trials data, which had been executed at Nashabia Irrigation Research Station, Damascus Countryside, Syria. The data that have been gotten of the net water consumption and number of irrigations for apricot, olive trees, tomato, and maize of field trials were compared with those results that have been gotten using the program . The results showed an increase in the estimated value as compared with real one for water consumption with a percentage of (1%) for apricot, and (23%) for tomatoes. The means differences between the estimated and real values, using T-test (paired samples) by SPSS showed insignificant differences for apricot, olive, and maize, except tomato where the differences were significant at 5% level of probability, also it was noticed in terms of the number of irrigations that there was a high matching between the estimated and real values for apricot, olive, and corn, but for tomatoes there was a difference in about 4 irrigations, this difference is due to the difference in crop coefficient values between the estimated program value and the calculated (real value). The simulation model curve of changes in soil moisture was similar to the changes in moisture in the field conditions to a large extent. Root mean square error (RMSE) values for water consumption of apricot, olive, tomato, and corn were as follows: 6.4, 14.5, 45.41, and 26.53 respectively, while the values of Index of Agreement (d) were as follows: 0.98, 0.83, 0.81, 0.94 respectively, which indicates a good matching between estimated and real values.
Key words: CropWat8, Water consumption, Irrigation scheduling.
Full paper in Arabic: