| Popis: |
Water is a limited resource, rare in some regions. Competition for limited water supplies has escalated substantially over the past decades. Attaining high performances in irrigation systems is therefore fundamental not only to control the demand for water but also to obtain higher crop gross margins and to achieve appropriate control of environmental impacts. Field evaluations of irrigation systems play then a major role, particularly when field data can be used to simulate alternative solutions that may help solving problems detected during evaluation. 10 field evaluations of drip irrigation systems operating in the irrigated areas of Vigia and Lucefecit (Alentejo, Portugal) to irrigate maize, melon and vineyards were evaluated. The evaluations have been carried out according to the methodologies proposed by the ASAE Standard EP458. The computed performance indicators are generally below those commonly expected for this type of systems. These results are due to poor design, inappropriate selection of equipment, and lack of support to farmers. Data from evaluations were used with the simulation model AVALOC for searching alternative design solutions that could be adopted to improve water use. The paper presents main evaluation results and the respective analysis, as well as the most relevant examples of alternative solutions that could upgrade the existing systems. Among conclusions, it is evidenced the need for appropriate support to farmers, both when they install a new system and for its management. |
