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DEPIVOT, A SOFTWARE TOOL FOR IMPROVED WATER USE WITH CENTER-PIVOT SPRINKLER SYSTEMS. Valín Sanjiao M.I . ; Santos Pereira L. Agricultural Engineering Research Center, Institute of Agronomy, Technical University of Lisbon. WATER SAVING IN MEDITERRANEAN AGRICULTURE & FUTURE RESEARCH NEEDS
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DEPIVOT, A SOFTWARE TOOL FOR IMPROVED WATER USE WITH CENTER-PIVOT SPRINKLER SYSTEMS Valín Sanjiao M.I.; SantosPereira L. Agricultural Engineering Research Center, Institute of Agronomy, Technical University of Lisbon. WATER SAVING IN MEDITERRANEAN AGRICULTURE & FUTURE RESEARCH NEEDS CIHEAM, Mediterranean Agronomic Institute of Bari, Italy
Design new systems Evaluation of operating systems Gross irrigation requirements End Start Computation of emitters chart Input data field Computation of performance indicators Hydraulic simulation Spans Emitters Systems Acceptable runoff? Occurrence of runoff THE MODELConceptual structure DEPIVOT, A SOFTWARE TOOL FOR IMPROVED WATER USE WITH CENTER-PIVOT SPRINKLER SYSTEMS N Y
THE MODELGross irrigation requirements DEPIVOT, A SOFTWARE TOOL FOR IMPROVED WATER USE WITH CENTER-PIVOT SPRINKLER SYSTEMS
THE MODELHydraulic simulation DEPIVOT, A SOFTWARE TOOL FOR IMPROVED WATER USE WITH CENTER-PIVOT SPRINKLER SYSTEMS
THE MODELSelection the emitter chart DEPIVOT, A SOFTWARE TOOL FOR IMPROVED WATER USE WITH CENTER-PIVOT SPRINKLER SYSTEMS
THE MODELCalculation of the application rate DEPIVOT, A SOFTWARE TOOL FOR IMPROVED WATER USE WITH CENTER-PIVOT SPRINKLER SYSTEMS Compare Run off
THE MODELPerformance indicators DEPIVOT, A SOFTWARE TOOL FOR IMPROVED WATER USE WITH CENTER-PIVOT SPRINKLER SYSTEMS
MODEL APPLICATIONPerformance indicators in field evaluations The results analyzed herein refer to field evaluations of center-pivot systems in operation in Alentejo (Portugal) DEPIVOT, A SOFTWARE TOOL FOR IMPROVED WATER USE WITH CENTER-PIVOT SPRINKLER SYSTEMS
MODEL APPLICATIONPerformance indicators in field evaluations • Main problems were: • high working pressure, ranging from 476 kPa to 555 kPa, much above recommended pressure for systems with FSPS emitters; • high wind drift and evaporation losses due to small diameter of droplets as a result of high functioning pressure of emitters; and • application rates excessive relative to soil infiltration rates. • These problems result of poor design, mainly relative to the selection of spray heads which were not in agreement with the existing characteristics of the pressurized distribution network and the characteristics of the soils and relief in the area. DEPIVOT, A SOFTWARE TOOL FOR IMPROVED WATER USE WITH CENTER-PIVOT SPRINKLER SYSTEMS
MODEL APPLICATIONPerformance indicators obtained in DEPIVOT The model DEPIVOT was used to simulate alternatives to the existing systems DEPIVOT, A SOFTWARE TOOL FOR IMPROVED WATER USE WITH CENTER-PIVOT SPRINKLER SYSTEMS
CONCLUSIONS The operation pressure is excessive DEPIVOT, A SOFTWARE TOOL FOR IMPROVED WATER USE WITH CENTER-PIVOT SPRINKLER SYSTEMS Runoff was also often produced due to high application rates Small drops that easily evaporate or are drawn by the wind Field evaluations of center-pivot systems have shown that these systems are often poorly designed and the selection of emitters is often inappropriate Friction losses observed were often greater than 20% of the operation pressure
CONCLUSIONS • The model DEPIVOT was conceived to support farmers in selecting new systems and improving the existing ones. • DEPIVOT shows that it is possible to: • achieve much better performances; • reduce the operating pressure and save energy; • control wind drift and evaporation losses, • control runoff DEPIVOT, A SOFTWARE TOOL FOR IMPROVED WATER USE WITH CENTER-PIVOT SPRINKLER SYSTEMS The beneficial water use.