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Optimizing water and nutrient management in orchards may allow significant improvement in yield and environmental protection. A spatially variable microsprinkler system for orchards was developed and a prototype was installed along 50 trees in a nectarine orchard. Individually addressable microsprinkler nodes were located at each tree. A drip line controller, storing the irrigation schedule and issuing commands to each node, was at one corner of the orchard. Each microsprinkler node included a standard microsprinkler emitter, a latching solenoid valve, and control circuitry. Pressure and soil moisture sensors connected to nodes provided real-time feedback on system conditions. Tests were conducted to evaluate individual microsprinkler control, accurate water application, and fault diagnosis. Continuous pressure monitoring allowed fault detection and accurate computation of water discharge by individual microsprinklers. The system was programmed to (1) irrigate individual trees for specific durations of time, (2) apply a specific volume of water at each tree, or (3) irrigate in response to soil water demand. The average error in specificvolume application was 3.7%. Fault diagnosis routines detected microsprinkler clogging or damage and drip line breaks or perforations. Microsprinkler faults were correctly identified in 359 of 366 attempts.