Managing The Effect Of Wheel Traffic On Forage Yields

Table of Contents

1. Effects of Wheel Traffic
2. Recommendations To Reduce Wheel Traffic Damage

Effects of Wheel Traffic

Hay fields have to be driven on to harvest a crop. Unlike haylage systems, where the forage is completely removed a day or 2 after cutting, dry hay harvest results in a great deal of wheel traffic that often occurs 5 days or more after cutting. Additional traffic activities include raking, baling and bale removal with a front-end loader tractor and wagons. Research began in 2000 in numerous U.S. States by Dr Dan Undersander (University of Wisconsin) and others, to investigate the effects of wheel traffic on alfalfa yield.

This research showed that there can be significant yield losses as a result of wheel traffic damage, and that some alfalfa varieties are more susceptible than others. Driving over the plots reduced subsequent yields (second- and third-cuts) by an average of about 25 to 30% in the wheel tracks. Typical operations of cutting, raking, baling and hauling results in about 25 to 30% of the field being in at least one wheel track, but this could be as high as 60%.

Traffic damage yield reductions are largely a result of the breakage and damage to new shoot regrowth. Soil compaction may play a much smaller role. Regrowth typically begins 5 days after cutting. The longer the delay after cutting, the more regrowth and the more damage results. Weakened plants may also result in a carryover effect to the following year.

Dr Steve Bowley, University of Guelph, investigated wheel traffic using some of the Ontario Forage Crops Committee variety plots at the Elora Research Station in 2003. This research showed a negative yield response to wheel traffic in grass species, as well as legumes.

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Recommendations To Reduce Wheel Traffic Damage

There is still much to learn about the significance of wheel traffic damage in dry hay harvest and management practices that can help to minimise it. Here are a few obvious recommendations:

• Harvest as soon as practical after cutting.
  
• Use smaller tractors where possible. For example, don’t use the big loader tractor to rake.
  
• Avoid unnecessary trips across the field.
  
• Collect large bales and remove them from the field as soon as possible after baling.
  
• If manure is going to be applied, traffic damage is another reason it should be done as soon as possible after cutting.
  
• Use “traffic tolerant” varieties when they become identified by research.
  

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