What causes a circle of dead lawn grass?

[JWR]

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.

Yep, agree. Fairy rings exist on my farm in a couple of places and are weird to see for the first time! I have never seen a fairy ring as small as the one pictured. Like Moss I'd guess that some chemical was spilled in that circle and probably seeped deep enough in the ground to adversely affect grass. Maybe grass killer in large concentrations or something BUT that stuff ordinarily wears off after a while. Maybe some previous owner worked with a machine there with oil or fuel spills that soaked deep?

 

[MossRoad]

Since the OP said he’s been there a number of years and it just popped up now, I’d lean towards his diagnosis of a fungus issue.

 

[Bruno0201]

I had similar semi circles in my pastures several times. It would take about a year for them to produce grass again. I found that when I filled my tractor up with diesel and made left turns, fuel would leak out of the fuel inlet around the cap and kill everything it touched. Not saying this is your problem but it took me a while to figure it out.

 

[Teck]

I have these on my place too. I usually get them under or next to my red oaks, but not always. This Consan 20 (see Pic) works for me. 1 TBSP per gallon. Don't get near a pond or other water ... It'll kill fish.

 

[John Atkisson]

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? ).View attachment 758212

 

[John Atkisson]

I had something like this in my front yard and it turned out a large tree was removed from that spot a few years earlier.

 

[lilranch2001]

I’m guessing back in the 1800’s someone stored pallets there…….

 

[stuckmotor]

A few weeks back, I found a dead spot in the grass up near a utility pole. After puzzling over it I remembered it was on the exact spot where I'd snagged the gas tank on a guy wire and knocked it off the gas tank on the previous mowing. My Snapper Rear Engine Rider has a lift out gas tank and when it came off it pulled the fuel hose loose.

 

[stuckmotor]

I've noticed fairy ring mushrooms several times. Only saw a definition for fairy rings when I looked them up just now.

 

[beenthere]

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? ).View attachment 758212

Suspect grubs might be doing that. Can you grab some of the dead grass and lift up a patch? If so, look to see if there are grubs eating the grass roots.