Variable-rate irrigation has the potential to save substantial water. These water savings will become more important as urban, industrial, and environmental sectors compete with agriculture for available water. However, methodologies to precision-apply water for maximum agronomic and economic utility are needed.  Information is needed to optimally management variable-rate irrigation systems. In this study, we conducted irrigation experiments on peanut to compare variable-rate irrigation management using traditional soil water potential measurements with an expert system (Irrigator Pro) for spatial crop management. We conducted experiments in 2007, 2008, and 2009 to evaluate Irrigator- Pro as a potential tool for variable-rate irrigation of peanut using a site-specific center pivot irrigation system developed by the USDA-ARS at Florence, SC.  Treatments were irrigation of whole plots based on the expert system, irrigation of individual soils within plots based on the expert system, irrigation of individual soils within plots based on soil water potential (SWP) measurements, and rainfed. Irrigator Pro managed treatments initiated irrigation earlier in the season than for treatments managed with SWP measurements. Total seasonal water applied was generally greater for Irrigator Pro treatments than for the SWP treatments.