Tynes are a cheap and easy option for no-till beginners. Tyne break-out needs to be at least 90 - 150kg per tyne and it can then be fitted with any of several knife or inverted T-points.  Note that knife points increase the lever-arm length, resulting in break-out at a lower soil strength (compared with sweeps). With combines, the boxes may need to be raised or a blower fitted to allow wide spaced tynes (70cm between bars, 70cm under frame).

Knife points with wider row spacings (> 220mm) can be an effective tool to fight herbicide resistance because they allow more effective use of trifluralin which is lightly covered by fine soil throw across the inter-row, provided no soil is thrown into the adjacent furrow.

Wider rows also reduce residue handling problems, capital costs, cost of wearing parts, draft, tractor size and fuel use. However, cereal yields can sometimes be slightly reduced with wider rows, as shown in Table 2, but the benefits may outweigh the negatives.  In fact, Table 2 shows that if a 270mm row space was adopted to avoid burning stubble, and that burning was necessary at 180mm row space, the system change of wider row and no burning (2.58t/ha) would give a higher yield over time compared to narrow row and burning (2.47t/ha).

A typical knife point. (Source: Agmaster.)

Disc seeders have the advantage that they can seed through a large amount of residue (with some hair-pinning), give accurate seed placement (important in marginal moisture conditions), disturb very little soil (reducing weed emergence and conserving moisture), require less draft (with savings in tractor size and life and fuel costs) and will not rip rocks up. However, it will increase the risk of fertiliser toxicity (unless the seed and fertiliser are separated). A wavy or turbo disc placed before double disc seeders is mostly beneficial as most soils require disturbance below seed placement depth. Care must be taken with discs to avoid smearing in wet clayey soils.

New research on improved disc seeder designs, which can cultivate like knife points, but handle stubble better, suggests there are no yield penalties for replacing a deep working knife point with a deep working undercut disc. Capital and running costs of disc machines are no greater than high-tech tyne seeders.

This triple disc opener allows fertiliser and seed separation.
(Source: Walkers Merredin, now supplied by Gessner, Toowoomba)

Soil disturbance (3 - 10cm) below the seed gives quick root growth and early vigour in sandy soils and can be achieved with discs or tynes. In clayey soils, shallow working points reduce draft, give better depth control, fewer clods, more even establishment and improve the ability of crops to compete with weeds.

Under-seed disturbance reduces rhizoctonia, which is a problem in some sandy soils. Point type does not seem to affect yields. Inverted T-points are not likely to increase yield over knife points in Western Australian soils and seeding conditions, as their action differs very little.

Rotary harrows improve soil cover over the seed and incorporate chemicals but also encourage more weeds to germinate. Press wheels reduce seed depth variation, and on moist clayey soils they often assist slot closure. Press wheels are useful on very sandy soils and on drying soils, especially where clods form, to assist with even seeding depth, improve seed-soil contact, and assist moisture flow through the soil to the seed, particularly on non-wetting soils. Harrows are now rarely used; most growers having invested in press-wheels, even though their benefits may not be apparent in all soils or years.