Our Casebook feature is popular with Grainews readers, and it generates quite a bit o mail. But we have never had as much interest in a case as we had with our story about fairy circles.
Many of you have had experience with this. This question (and photo above) came to us from Warren Bepple:
I was interested in seeing a crop circle article in the February 21, 2017, Crop Advisor’s Casebook. Those circles look like what we call fairy circles caused by wild mushrooms.
The attached photo shows some circles we have in one part of a field. The photo was taken in 2016, from a drone at a height of 80 meters. The top left green portion is a new seeding of barley. Our farm is a small farm in B.C., outside of Kamloops, at an elevation of 1,100 meters, so we are not big time grain farmers.
The circles vary in diameter from one to five meters. When I first saw them I thought of the fairy circles since we do have them in some other fields, but there were no mushrooms evident here and the field had been plowed in the spring, which should have disturbed the circle.
I dug down about two meters across one ring but could not find anything that looked different than the surrounding soil. The dark vegetation in the circle was higher than the surrounding vegetation. The water table was at two meters.
Do you have any suggestions?
I checked in with the author of our Casebook story, Josefine Bartlett. Josefine, who works for Richardson Pioneer Ltd. in Fairview, Alta., had this answer for Warren:
Thank you for submitting your answer to the crop circle problem. I was also very interested in the crop circle scenario on your farm in British Columbia. From your photos, the rings in your crop look similar to those caused by fairy ring fungi, however, it’s difficult to diagnose this casebook from the photos for a few reasons.
For example, although you couldn’t find any mushrooms in your crop circles, if the region was experiencing drier weather conditions, mushrooms may not develop. Usually, under milder weather conditions and rain, mushrooms show up more prominently.
In addition, you mentioned when you dug down in the soil profile, there was no evidence of fungi, or anything else out of the ordinary. Mycelium, the vegetative part of fungi, has a whitish-coloured, thread-like network that should be evident in the soil profile. You also mentioned that you had plowed the field in spring. Plowing should have broken up and disturbed the mycelium, but not necessarily killed it.
Unfortunately, there is not much one can do to eradicate these crop circles. However, generally, they do not cause yield reductions.
There is limited research done on fairy rings in western Canadian crops. Thus, there is no data or advice on how to eradicate these rings. In the turf grass industry, more research has been conducted, however, fairy rings are still proving to be a greenkeeper’s worst enemy. Research indicates soil fumigation (which is very pricey) or excavation can eradicate the fungi. In addition, methodically watering and fertilizing turf may also suppress fairy rings. However, these methods are labour intensive, and no economic thresholds have been determined for the crops we are concerned with.
I hope this information helps you to uncover the origin of the crop circles on your farm.
Thanks to Warren and everyone else who got back to me with comments about this case. Personally, I’m still a little disappointed that Josefine couldn’t prove they were aliens.