FIELD TESTS OF OSIRI - A DECISION-MAKING TOOL FOR IRRIGATION OF SUGARCANE FARMS IN REUNION

摘要

A decision-making software tool for monitoring irrigation of small farms in heterogeneousrnenvironments (OSIRI) was developed at the request of small-scale sugarcane farmers on thernisland of Réunion (France) hampered by variable climate and soil conditions. This program,rnwhich is based on a simple water balance simulation model coupled with a comprehensive setrnof decision rules, was designed to provide farmers with customized advice on discreternirrigation units and to simulate irrigation system scenarios so as to optimize theirrnperformance. The basic equations and main decision rules of OSIRI, as well as the softwarernfeatures, were given in Chopart et al. (2007). A detailed experimental study was carried outrnon a 5000 m~2 irrigated sugarcane field to compare the performance of this tool with therncurrently used method based on maximum crop water requirements (control). The resultsrnshowed that OSIRI reasonably well simulates actual evapotranspiration and drainage belowrnthe sugarcane root zone. Moreover, it allowed savings of about 26% in irrigation deliveryrnthroughout the crop cycle as compared with the control method, without a significantrndecrease in yield, and irrigation water productivity increased by 25%. The results of a surveyrnof 25 farmers using OSIRI showed that it is a well accepted valuable decision-making tool.