Photographs of the granular product for short vanes and orifice positions 32 and 43 were taken through one of the apertures (150–1908). No significant (95%) influence of the mass flow rate on the behaviour of the horizontal angle of flight was found for this configuration and fertiliser (Fig. 4). Olieslagers (1997) reported no significant overall influence of the mass flow rate as well, but Heppler (1993) found an influence in some cases.