The effect of controlled traffic on soil physical properties and tillage requirements for vegetable production

• The use of heavier machinery has increased soil compaction.
• Controlled traffic is an effective means of managing soil compaction.
• Controlled traffic improves soil physical properties and reduces tillage operations.
• Benefits are difficult to maintain with current vegetable industry machinery.

Demands for increased work rates and more timely operations in vegetable production have led to the use of more powerful and heavier machinery over the past 20 years. Increased vehicle weight, frequency of tillage, and capacity to work soil at sub-optimal moisture contents has increased soil compaction, and the tillage effort required for remediation. Despite conclusive evidence from other industries that controlled traffic systems improve soil conditions, reduce inputs, and overall improve productivity, such systems have not been widely adopted in vegetable production. Trials were established on red ferrosols in northern Tasmania to determine the effect of controlled traffic on soil compaction and penetration resistance, and the number of tillage operations required to prepare a seedbed for vegetable production. Potential mechanical, logistical or agronomic barriers to adoption of controlled traffic systems in vegetable production were also identified. Controlled traffic treatments demonstrated improvements in soil physical properties, and 20–60% fewer tillage operations, compared to conventional production systems. However, the measured benefits of controlled traffic were variable over the duration of the research studies due to limitations of current mechanisation. Adoption of controlled traffic in the vegetable production sector is currently limited by track gauge and working width incompatibility across the diverse range of equipment used, and machinery tracking issues associated with undulating topography.