Development and field evaluation of a high-speed no-till seeding system

The majority of no-till seeding systems use straight narrow point openers which cause excessive soil disturbance and stepping when operating at speeds above 8 km h(-1), resulting crop emergence and yield losses. A bentleg opener is a low soil disturbance alternative that can enable higher operating speeds. To be successfully integrated into a seeding system, the bentleg opener must accurately place seeds, band (separate) fertiliser and spatially separate seeds from soil applied herbicides to maximise crop safety. In this study, two seed and fertiliser banding techniques; placing seeds into backfilling soil with a closer plate; and placing seeds on an undisturbed ledge in the furrow (side-banding) were used to develop two higher speed bentleg seeding systems. The seeding systems were evaluated using field experiments and discrete element method (DEM) simulation. Results showed both bentleg seeding systems could increase operating speeds by at least 50% (8 to 12 km h(-1)) with no penalty to wheat crop emergence or yield. In contrast, seeders using straight narrow point openers, increased seeding depth by 26 mm due to stepping at 12 km h(-1), thus reducing emergence by 31%. Side banding bentleg seeding systems provided the most accurate seed placement but caused minor stepping (+ 6 mm seeding depth at 12 km h(-1)). The low disturbance bentleg seeding provided adequate separation from soil applied herbicides in this sandy loam evaluation, measuring no significant emergence or loss yield with three different herbicides. Bentleg seeding systems thus offer an opportunity for higher seeding speeds without crop losses.