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“Dripping with success”: the challenges of an irrigation redevelopment project

Merry, R.E.
Irrigation and drainage 2003 v.52 no.1 pp. 71-83
audits, controllers, cost analysis, crop production, fertigation, furrows, irrigated farming, irrigation scheduling, irrigation water, microirrigation, pumps, radio, sprinkler irrigation, sprinklers, subsurface irrigation, sucrose, sugarcane, surface irrigation, water conservation, water resources, Swaziland
Irrigation is vital to sugarcane production at the Simunye sugar estate in Swaziland. When full commercial production commenced in 1982 the estate had two main irrigation systems, dragline sprinkler and surface furrow, but in later expansions surface drip irrigation was used. By the mid-1990s there was increasing demand on water resources for further sugarcane expansion and with the infield sprinkler equipment showing signs of wear and tear, Simunye estate looked into irrigation redevelopment. A cost analysis of seven different irrigation options was undertaken and the one that offered the best return was conversion of the dragline sprinkler system to subsurface drip. The redevelopment project commenced in 1998 and so far 4000 ha have been converted from sprinkler to drip. The system design uses a novel cluster house concept for controlling irrigation water and fertigation to cane blocks of about 100 ha. Radio controllers are used to provide automatic operation of pumps, valves and irrigation schedules. A post-investment audit conducted in 1999 confirmed a sucrose increase of 15% and water saving of 22% compared to the sprinkler system, better than originally expected. Further analysis undertaken in 2001 revealed even better figures.