With the push to become more energy and resource efficient, Controlled Traffic Farming (CTF) in cropping paddocks is becoming an accepted practice for many broadacre farmers.

The wheel tracks of machinery used for cropping are matched to allow them to run on the same permanent wheel tracks.

This technique is often part of a zero-till cropping system and uses a guidance system which can be as simple as a marker disc or as sophisticated as the various Global Positioning Systems available.

Research has shown that up to 50 per cent of a paddock can become compacted under normal tractor traffic by multiple passes required to prepare, sow, spray and harvest crops.

Using CTF, this can be reduced to 15pc.

Compaction in the root zone reduces the size and number of soil pores that can hold water and air; hence it limits root growth, reduces rainfall infiltration and soil biological activity.

Soil volume available to the crop remains the same; it is only the surface area that is affected by permanent tracks.

Despite the fact there is a reduced area sown to crop in the controlled traffic paddocks, yields increased by 15pc in non compacted areas.

There are other benefits with controlled traffic, including reducing the tractor power requirements by up to 50pc due to reducing wheel slip and eliminating the need to till compacted soil.

This will result in lower fuel consumption.

Improving the accuracy of all paddock operations reduces overlap of sowing and spraying which can decrease time and resource inputs by up to 15pc as well.

Another advantage is that tramlines can enable spraying for weeds and fungal disease problems to be done at exactly the right time, maximising chemical efficiency.

Many farmers start off in CTF by matching the seeder and sprayer wheel tracks; harvesters are more difficult to fit into the system and generally soil damage is minimal under dry harvest conditions.

However, a wet harvest can result in substantial soil compaction, so the benefits of having the harvester in the system would then become apparent.

Crops can be grown on wider row spacing on some soil types, which allows spraying down the rows rather than blanket sprays, saving chemicals.

Controlled Traffic Farming is not without its drawbacks, as it fits in best with a zero till system, on flat, open country, that uses continuous cropping and does not have livestock in the rotation.

Negotiating hilly paddocks, with scattered trees and rocks with a guidance system is quite a challenge.

The unplanted wheel tracks can also lead to weed invasion and are more susceptible to erosion.

So there is still some development work to be done to perfect controlled traffic farming.

For more information there is an Australian Controlled Traffic Farming Association; see references on the GRDC website or contact me on 02 6942 4957.