Abstract: An agricultural irrigation system having a fluid dispersion nozzle for controlling the flow rate and generating a resultant fluid stream characterized by uniform dispersal along the stream path. The nozzle has a housing member (10) which defines an inlet passageway (16), a nozzle outlet orifice (32), and an intermediate fluid chamber (30). A resilient flow control member (34) is located within the fluid chamber (30) and has an orifice (36) centrally located therein and axially aligned with the inlet passage (16) and the nozzle orifice (32). The nozzle orifice has located along the inner periphery thereof a plurality of circumferentially equally spaced and radially inwardly projecting deflector members (38, 40, 42) which are effective for reducing a portion of the resultant fluid stream velocity therethrough. The fluid dispersion nozzle is mounted on a rotary sprinkler head (50) which receives a supply of pressurized irrigation fluid from an irrigation system primary conduit (56).