<P> Originally, most center pivots were water - powered . These were replaced by hydraulic systems and electric motor - driven systems . Most systems today are driven by an electric motor mounted at each tower . </P> <P> For a center pivot to be used, the terrain needs to be reasonably flat; but one major advantage of center pivots over alternative systems is the ability to function in undulating country . This advantage has resulted in increased irrigated acreage and water use in some areas . The system is in use, for example, in parts of the United States, Australia, New Zealand, Brazil and also in desert areas such as the Sahara and the Middle East . </P> <P> The center - pivot irrigation system is considered to be a highly efficient system which helps conserve water . </P> <P> Center pivot irrigation typically uses less water compared to many surface irrigation and furrow irrigation techniques, which reduces the expenditure of and conserves water . It also helps to reduce labor costs compared to some ground - irrigation techniques, which are often more labor - intensive . Some ground - irrigation techniques involve the digging of channels on the land for the water to flow, whereas the use of center - pivot irrigation can reduce the amount of soil tillage that occurs and helps to reduce water runoff and soil erosion that can occur with ground irrigation . Less tillage encourages more organic materials and crop residue to decompose back into the soil, and reduces soil compaction . </P>

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