DESIGN OF CENTER PIVOT IRRIGATION SYSTEM BASED ON SIMULATION MODEL TECHNIQUE

Abstract

Centre pivot irrigation system is a promising and precise system, for increasing the utilization efficiency of unit water. Hence, A CPIM simulation model has been developed and validated, however, A CPIM model is based on crop type, weather data, and soil characteristics. The model comprises five sub-models for: (a) main sub-model; (b) data entry sub-model; (c) weather sub-model; (d) irrigation sub-model; and (e) results sub-model. The most important simulation outputs of the CPIM model include nozzle flow rate (m3/h), application rate (mm/h), and throw diameter (m). These outputs (outputs of 9 scenarios) were compared with observed/manufactured data for the calibration and validation of the model. Results of this comparison show that differences in model accuracy owing to different variables affecting the design and management of the center pivot were not significant. The relationships between the observed/manufactured and simulated results have a good correlation with high value of coefficient of determination and the best models are as follows: 1- Nozzle flow rate (m3/h) was in scenario 5 with R2 = 0.967 and explained by an exponential model: Q SIM = 0.1067e4.1131 (Q obs). 2- Application rate (mm/h) was in all scenarios with a very high R2 and explained by a linear model. 3- Throw diameter (m) was in scenario 1 with R2 = 0.942 and explained by a power model: Dw SIM = 3.9064 (Dw MFD)0.4361.