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International Conference on Water Saving in Mediterranean Agriculture & Future Research Needs 14-17 February 2007, Bari, Italy. ASSESSING THE SIMDualKc MODEL FOR IRRIGATION SCHEDULING SIMULATION IN MEDITERRANEAN ENVIRONMENTS.
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International Conference on Water Saving in Mediterranean Agriculture & Future Research Needs 14-17 February 2007, Bari, Italy ASSESSING THE SIMDualKc MODEL FOR IRRIGATION SCHEDULING SIMULATION IN MEDITERRANEAN ENVIRONMENTS J. Rolim, P. Godinho, B. Sequeira, Paula Paredes, L. S. Pereira Agricultural Engineering Research Center, ISA, UTL, Tapada da Ajuda, 1349-017 Lisbon, Portugal, lspereira@isa.utl.pt
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments • Introduction • The dual crop coefficient approach • SIMDualKc Model structure • Model validation • Results and discussion • Conclusions
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments 1. Introduction SIMDualKc is a software tool to simulate the soil water balance by computing ETc and perform soil water balance simulation based on the dual crop coefficient (Kcb + Ke) approach. • ETc = (Kcb + Ke) ETo
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments • Model main goals: • computing crop water requirements and irrigation scheduling, mainly focusing vegetables and orchard crops, partial cover crops, mulched soil, high frequency irrigation; • improve accuracy in irrigation programming; • making available an accurate and easy to use simulation tool; • advising irrigators. • SIMDualKc model applies: • atfield level; • with daily time step; • to real-time irrigation scheduling when meteorological data is available, assessing the evolution of the soil water content
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments 2. Dual crop coefficient approach The dual Kc approach (Kcb + Ke) shall produce more accurate ETc estimates for regions with frequent rainfall, in high frequency irrigations, and partial cover crops. Partitioning Kc into Ke and Kcb components allows better following the impacts of wetting the soil by rain or irrigation, as well as the impacts of keeping part of the soil dry, or using mulches for controlling soil evaporation.
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments Results 3. Model structure The model was developed using a three tiers architecture approach: database, mathematical model and a graphic user interface (GUI) Mathematical model Modules: - Kcb computation - Kcb adjustment - Ke computation - ETc computation - Soil water balance Data Base - Soil - Climate - Crop - Simulations Graphical User Interface Dialog structure
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments SIMDualKc flowchart • Two abstract interfaces are used: • one to link the computational module with the GUI or with the selected model; • other to connect the numerical modules to the database, through queries that enable to adapt different databases to the data structure of SIMDualKc including GIS;
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments SIMDualKc core algorithm & methodology (FAO56)
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments Soil data menu Main Menu
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments Crop menu Meteorological data menu
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments climate crop + soil + Field representation Model inputs
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments Model outputs Kc and depletion curves
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments Export table of results Model outputs
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments Model validation SIMDualKc validation was performed: • using field and meteorological data collected in various experimental fields; • by comparing observed and simulated soil water content values using a regression through the origin. • Mediterranean basin • Portugal (Maize) • Tunisia (Winter wheat) • Syria (Winter wheat) • Italy (Citrus) • Central Asia (cotton)
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments TAW 3 basin irrigation events OYT Results – Portugal (Maize)
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments 2 basin irrigation events Results – Portugal (Maize)
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments Supplemental irrigation with furrow irrigation Results – Tunisia (Winter wheat)
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments Sprinkler irrigated Results – Syria (Winter wheat)
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments Sprinkler irrigated Results – Syria (Winter wheat)
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments Microsprinkler irrigation Results – Italy (Citrus)
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments Furrow irrigation Results – Central Asia (Cotton)
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments Summary of Results
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments Conclusions 1. The SIMDualKc validation show good adherence of model results to field observations; • 2.The model accurately follows the evolution of soil moisture along the crop season: • proves to be particularly satisfactory in the simulation of soil water balance during initial stages of development; • this indicates that computing ETc with the dual approach is highly accurate;
Assessing the SIMDualKc Model for Irrigation Scheduling Simulation in Mediterranean Environments Conclusions 3. The model shows to be able to support farmers’ advice as well as to predict ET and irrigation requirements for planning and environmental studies; 4. The model presents high capability to simulate the soil evaporation component and constitutes an important support for irrigation and soil management.
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