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avoid transporting weed seeds

Weeds can be introduced to new areas from a variety of natural and human-influenced sources. Seed transport on vehicles or equipment can be a very important mechanism of spread.

Montana State researchers measured the number of seeds picked up by a variety of vehicles and the distance traveled before the seeds fell off. Among their key findings:

Recommended Prevention Techniques

As an added measure of protection, land managers in areas where high-risk invasive species are growing are advised to close the area to traffic when the ground is wet. Doing so will dramatically reduce the risk of transporting weed seeds to new sites and also reduce future weed management costs.

Montana State researchers evaluated the ideal duration and number of washes needed to remove weed seeds. Vehicles washed once for six minutes or two to three times for three minutes each were judged to be the most seed-free. Five portable commercial wash units were tested, and each performed similarly, regardless of the water pressure or the amount of water used. Four of the units had undercarriage washers as well as pressure hoses, which made removal of dirt from the underside much easier.

Prevent spread of resistant weeds
Waterhemp is an example of a potentially herbicide-resistant species that may need to be contained, especially when it is out of control in only a few fields on the farm. Palmer amaranth and bur cucumber are examples of two species that may be either new or in few enough fields that it is valuable to prevent them from spreading further. These species are especially difficult to manage, and preplanning harvest can help reduce problems in future years.

Prior to harvest, scout fields for escaped weeds since weeds are easier to see after crops have matured. This is important to identify problem fields or areas for next year. Your notes about weed problems are critical to choosing effective management tactics for next year, so make this a priority before harvest.

WEED SEED SPREADER: Harvesting equipment can carry a significant amount of material, including weed seed, between fields.

Clean out combine between fields
Finally, take steps to minimize movement of weed seed between fields on harvest equipment. In the future, new technology like the Harrington Seed Destructor will make weed management at harvest simpler, but until then, relying on good cleanout practices is necessary in some situations.

In some situations, scattered weeds could be removed from the fields prior to harvest. It is much easier to manage weeds before they drop mature seed or before that mature seed goes through a combine.

Harvest is just around the corner for many Iowa farmers, and now is a good time to consider options to reduce movement of weed seed between fields with harvest equipment. Combines are extremely effective at transporting seed from field to field. A few precautions leading up to harvest and during harvest can help manage any escaped problem weeds.