Tillage: barely there by Guy Cotsell

Farmers are evaluating new technology zero-tillage openers which virtually eliminate soil disturbance at sowing.

The zero-tillage machines cut through stubble and leave a fair amount still standing. Farmers in Canada and the USA are rapidly adopting this technology.

Current direct-drill and minimum-till systems can actually cause a lot of soil disturbance. Most seeding equipment is developed from the basic tined machines originally designed to sow wheat. Many have so many tines that the ground is pretty well worked over by the time the rolling harrows have done their job. Stubbles tend to end up flat on the ground or have to be mulched to pass through the seeder.

With the new zero-tillage machines the seeding process is totally different. A small slot is opened by a disc, the seed dropped in, and the slot closed by a press wheel. It is difficult to see where the drill has been, and very hard for birds to dig seed up once it is pressed into place.

Three openers trialed

Southern Farming Systems (SFS) evaluated three commercial openers at a number of sites in south-west Victoria. Two of the openers — marketed as Barton and Conserva-Tech, both built in Canada — had the disc set at about 30 degrees to vertical, and slightly offset from the direction of travel. The press wheel runs at an angle to the disc so that the seed is pressed firm but a loose crack is left for the seed to emerge.

The third opener, New Zealand-designed Bioblade, has an inverted disc with an inverted T-boot on either side, like a Superseeder point cut in half with a disc running through it. This opener gives cultivation below the seeding depth as well as separating the placement of seed and fertiliser. This separation can be arranged at different heights on either side of the disc.

Barton openers are distributed by Flexicoil, Conserva-Tech by Ian Geddes, Lake Bolac, and Bioblade by Namoi Valley Implements at Narrabri.

Advantages expected from the openers are:

  • better soil structure resulting from minimum disturbance
  • “fantastic” stubble handling — no mulching or harrowing
  • constant seeding depth, even in undulating ground
  • yield increase with legumes, due to reduced evaporation and less disease
  • reduced weed germination
  • safe sowing after tank-mix spraying of herbicide — one less boomspray pass.

Detailed results of the trials of the three openers will appear on the Web, and are currently available to SFS members. Membership details are available from SFS on 03 5229 0566.

A number of farmers have an earlier acquaintance with triple-disc and double-disc openers o f various makes which were trialed in Western Australia during the 1970s. The Southern Farming Systems trials, however, focused on the newer angle disc and slot disc technology, which may be more robust and better suited to Australian conditions — Ed.

Program 3.5.2 Contact Dr Bill Gardener 03 5383 8288

Region North, South, West