The Seed Placement Test Rig at the University of South Australia is being used to compare seed placement accuracy for a variety of seed metering methods, seed delivery methods, soil openers and post seeding methods.
Success of this project has led to an Australian Research Council collaborative grant to the University of South Australia and machinery manufacturer Agroplow, of Wellington NSW, aimed at developing a new commercial seeder.
Engineering of the test rig, developed in 1990, was based on findings that plants get off to faster emergence and growth with spear-type points for seeding, compared with commonly used narrow lucerne chisel points on all soil types. The spear point has performed as well as the combine type on all soils. On sandy soils the airseeder type was superior.
A related study conducted by the University and the South Australian Department of Primary Industries defined optimal press wheel pressures. South Australian farmers who have fitted press wheels to their seeding machine are reporting yield increases from five to 20 per cent in wheat and barley harvests with related dollar dividends
Best emergence and plant growth is achieved at 5 kg/cm of press wheel width in contact with the soil on medium to heavy soil types, and at 2 kg/cm for light to medium soil types. The optimum seeding depth is 25-35 mm on medium to heavy soils, and 45-65 mm on lighter soils.
Manufacturers are Manutec Pty Ltd and Agricultural Rubber and Plastics.