The Fate of Weed Seeds: Where Do They Go in a Combine?

Weed seeds vanish from our view when they enter a combine at harvest, but Virginia Tech researchers want to unmask the mystery of their fate. 

That’s what Eli Russell, a Ph.D. student working under Virginia Tech Weed Scientist Michael Flessner, is tackling. Together with his VT team members, Matt Spoth, Cynthia Sias, and Kevin Bamber, Russell has been gathering data on harvest weed seed control for two years in wheat and soybeans. 

In the search to document a weed seed’s wild ride through a combine, Russell and the VT team collaborated with Virginia farmer Kenton Moyer on his operation, Iron Gate Farms, in Powhatan. 

By feeding known quantities of weed seeds into a combine as it runs through a soybean field, the researchers can simulate the effect of combines running through weedy patches in a field. A tarp attached to the back of a combine catches the chaff fraction – which would normally feed into the integrated Harrington Seed Destructor, attached to the rear of the combine. Another, larger tarp catches the straw fraction of the residue, which is blown out across the field as the combine runs. Knowing which tarp catches more seeds can help researchers learn how well a weed seed destructor can work to keep a field weed-free after harvest. 

Watch how the VT research team executes this tricky field experiment and learn how they will measure where the weed seeds ended up – in the chaff, straw or grain tank.

For more on harvest weed seed control methods, see this GROW webpage:

Video by Claudio Rubione, GROW; Text by Claudio Rubione and Emily Unglesbee, GROW.