Application of STICS Model in Assessment of the Effects of Irrigation Practices and Soil Properties on Yield of a Durum Wheat (Triticum durum Desf.) Cultivar in the Irrigated Area of Oued Rmel in Tunisia

The progress in computer technology has enabled the development of crop models reproducing the behavior of a crop in a wide range of pedoclimatic conditions and technical itineraries. This work aims to study the impact of total available soil water in the root zone (TAW) on durum wheat yield (Triticum durumDesf.) as affected by irrigation regime in Mediterranean climatic conditions of Tunisia. In this work, STICS model was used to simulate effects of farmer’s irrigation practices in wheat in the pedoclimatic conditions of the irrigated area of Oued Rmel in Tunisia over a 20-year period. Assessment of irrigation practices in the study area was performed, compared to rainfed system, in terms of yield and produced biomass at harvest. The model was calibrated to simulate the growth and development of winter wheat using the field observed crop data collected from three growing seasons in two locations in Tunisia. To carry out the study, three types of soil (S1, S2 and S3) in the Oued rmel irrigation scheme were chosen on the basis of their available soil water in the root zone (TAW). The study showed that the model adequately predicts crop yield and biomass. Simulation results showed that the farmers’ irrigation practice results, in higher grain yield and dry matter at harvest as compared to rainfed system. Simulated grain yield was significantly higher in soil with high TAW than in the other soils. Results showed that the highest difference (30%) in simulated grain yield, between the two water regimes, was obtained in soil having high TAW. Depending on the soil type, simulated dry matter at harvest increased from 4% to 12% compared to rainfed system.