What causes a circle of dead lawn grass?

[Fuddyduddy1952]

I our front yard is a 20 foot diameter circle of dead grass, about 6" across. It may be hard to see in picture but you clearly see in foreground dead lawn and it's really almost a perfect circle.
I've had my soil tested by agricultural laboratory and it came back excellent except a little high in nitrogen. Rest of lawn (over an acre) is fine. Septic lines and tank is way away in back yard. No underground wires, phone, AC, pipes, etc.
Over the years any bare spot I lightly raked, seeded, then thin layer of potting soil, straw on top & it does great.
I've seeded this, doesn't help. Any idea what causes this? It's weird. (Aliens? ).

 

[/pine]

How long have you lived there?...it almost looks like there could have been an above ground pool there ?

 

[RjCorazza]

I've seen dark green circles that are caused by fungus growth on abundant organic matter. In my area they're called fairy circles. If there was ever a tree in that spot I would guess fungus, but the fungus will grow outwards in a circle regardless.
Also could be a buried structure? Maybe the foundation of an old silo?

 

[MossRoad]

There are fairy rings that are fungus, but they are usually greener than the grass, not dead grass.

My 1st guess would be someone turned around while dripping/spilling weed killer.

When we 1st bought our 20 acres back around 1989, it was a farm field. All sand. There was an almost perfect circle about 30’ in diameter where nothing would grow except one type of weedy grass. Outside of the circle, any and all types of weeds and grasses would grow. Inside that circle, only 1. It took a good 5-6 years before anything else would grow there.

Our conclusion was that the farmer over-applied weed control while turning a circle or two.

 

[Raul-02]

What causes a circle of dead lawn grass?​

20 foot diameter circle of dead grass,

Crane Flies their grubs more precisely Bayer Bioadvanced 24 hour grub killer plus

 

[Hay Dude]

Was there a farm on your property?
The circle looks slightly proud of the lawn.
My guess is a silo or maybe a circular pool/fountain foundation

 

[duffer]

At first glance I was going to say grubs too, but since it's almost a perfect circle, that kind of DQ's grubs. I'm leaning more in the camp of spilled weed killer, or a hydraulic leak while turning around.

How long has the circle been there? Just this year, 5 years, what?

If it's been there (and hasn't grown in size) for more than a year, I would get a probe and see if RJ isn't right with his "buried foundation" suggestion.

 

[bobmisi]

From my experience it is dollar spot or brown patch or something similar and you need to treat it with a fungicide. May take more than one treatment. It can be spread to other areas of your lawn by just mowing. I prefer liquid treatment to granular.

 

[grsthegreat]

You guys are all wrong

 

[MossRoad]

You guys are all wrongView attachment 758228