A center pivot irrigation system is described that includes a controller that makes use of a particular flow rate of input water to deliver differing or variable depths of irrigation to two or more user-defined areas under a pivot irrigator. The controller operates to pulse control valves for the nozzles/sprinkler heads on and off as the sprinkler arm rotates. The valve pattern along the span of the sprinkler arm is chosen during each operating cycle such that the total water flow through all the open valves matches the flow rate of the input or supply water to the pivot irrigator. To ensure the variable application depth, the speed may be changed during valve duty cycles. A farmer may define an irrigation plan that defines the variable rate irrigation (VRI) zones and also defines exclusion or no spray zones in which no irrigation should occur.
