Controlled traffic for pyrethrum production in Tasmania - potential benefits and constraints

Controlled traffic keeps all paddock traffic in the same wheel tracks, thereby separating compacted traffic zones from soil used for growing crops. Although controlled traffic research has spanned many countries and decades, the Australian grain and cane industries are the most advanced in commercial adoption of the practice. Research and commercial experience has demonstrated a range of benefits including more efficient energy, water and fertiliser use, and improved soil structure, timeliness and productivity. As a short-term perennial crop, the traffic intensity of pyrethrum production is much lower than vegetable cropping, which generally occurs in rotation with pyrethrum in Tasmania. Therefore, it might be considered that pyrethrum production does not have sufficient traffic intensity to gain benefits from controlled traffic. However, once the crop is established, the annual traffic regime of spraying, windrowing and harvesting is very similar to the traffic regime of zero-till grain production, which has gained many benefits from controlled traffic farming. Constraining wheel traffic to defined tracks should provide more friable soil in the inter-track areas, which should lead to better infiltration and drainage, and may provide conditions which are less conducive to soil borne diseases. It is not known if the concentration of harvest traffic in the same tracks will have a detrimental impact on plants in those areas.