A boom mounting assembly (20; 120; 220) for attachment to an agricultural application machine (10) is provided. The assembly comprises a boom support frame (22) which is suspended from a primary frame (24) mounted to a chassis. The boom support frame comprises a transverse beam (35) for supporting an intermediate section of a fluid application boom (16). The suspension mechanism allows both yaw and pitch of boom support frame relative to the primary frame resulting from fore and aft forces on the boom. Dampers (50, 52) are each connected between the primary frame and the boom support frame at a position spaced from the transverse centre of the assembly. Damping of pitch and asymmetrical yaw movement of the transverse beam away from a neutral position is controlled by the first and second dampers.