Heavy cropping machinery is a major cause of surface and subsurface compaction in agricultural soils. Subsurface compaction reduces plant root access to water and nutrients limiting grain yield. 

Controlled traffic farming is a long-term strategy for minimising the impact of compaction on crop yield. The aim is to match the operating width (or multiples of, i.e. 12m header, 36m sprayer and 12m seeder) and wheeltrack width of all cropping machinery confining compaction to internal roads and leaving untrafficked root beds for crops. For heavy clays soils that have natural shrink and swell characteristics simply removing traffic can be enough to allow the soils to self repair the damage from compaction. However sandy textured soils may require some mechanical removal of the hard compact layer using deep tillage.

The average Australian no-till system drives over40-60% of the paddock in one season. If eighty percent of compaction occurs in the first pass then the benefits of removing are quickly undone. A fully matched CTF system has a trafficking percentage of 9-12%. CTF also offers other benefits including improved in-crop access, better soil aeration and drainage of heavier textured soils (loam or clay) in wet conditions, less fuel use and reduced greenhouse gas emissions.

Matching machinery can be challenging if there is little matching in the farm fleet. Developing a plan for CTF and implementing it in line with the farm machinery replacement schedule is a good strategy. Many successful CTF farmers have taken 6-10 years to have a fully matched CTF system. See the Controlled Traffic Farming Manual for more information.


This calculator has been produced by Department of Agriculture and Food WA's GRDC funded project DAW00243 Minimising the impact of soil compaction on crop yield. It was developed from the Wheeltrak Calculator produced in 2015 by Precision Agriculture Pty Ltd and funding partners including the Australian Controlled Traffic Farming Association, Southern Precision Agriculture Association, CTF Alberta, Beyond Agronomy, Condamine Alliance, Fitzroy Basin, Department of Agriculture and Food WA and the Grains Research and Development Corporation. We would also like to acknowledge the guidance and support provided by the Queensland Department of Agriculture and Fisheries. 

Software Engineering was undertaken by DHM Environmental Software Engineering Pty Ltd.