An improved distribution system for chaffy seeded grasses

Abstract

Lack of seeding equipment that will spread chaffy seed uniformly has impeded the improvement of pastures in Australia. A semicircular seedbox with a pickerwheel and auger agitator (SPAA) developed in Texas, USA was tested with three Australian grasses and compared with the Australian revolving drum seeder. The metering units were tested for change in discharge rates as the seedbox emptied. Modifications in the original SPAA device improved performance. Modifications included a change in the shape of the pickerwheel and the addition of a small post at the base of the seedbox just ahead of the pickerwheel. A pillar protruding from the top of the seedbox was also tested and found to have minimal effect on performance. At pickerwheel speeds of 10 and 30 rpm, the modified SPAA device experienced a 16 and 14% decrease in discharge rate as Cenchrus ciliaris L. cv. Biloela (buffel grass) seed was metered from 140 to 20% of seedbox capacity. In a comparable test, the revolving drum seeder experienced an 7-fold increase in discharge rate. Bothriochloa insculpta cv. Hatch (creeping bluegrass) and Danthonia richardsonii cv. Taranna (wallaby grass) seed were successfully distributed by the improved SPAA system. Based on these data, the improved SPAA metering device can distribute chaffy seeded grasses evenly, providing a means to sow these grasses effectively in pastoral areas of Australia.