Cats are territorial, you have to take a bigger shit on top of theirs to show dominance.

Robot lawnmower.. Damn

motion activated sprinkler

predator pee scent in your lawn

hot pepper flakes around your lawn

put trap boxes out with bait inside, catch the cat

A motion activated or retomely deployable sprinkler system would work wonders. No need for drenching the critter, just interrupt or annoy the cat. After a few forced baths, the cat would associate shitting on your lawn with getting wet and just move to safer grounds.

Sprinkle catnip all over a neighbor you don't like (the owner?) yard.

Accept that animals shit outside.

@PlutoniumAcid i’m 64, i’ve lived in over a hundred different places, including rural and suburbs with lawns. literally never ever had this problem. not even when i owned cat! so it seems you’re cursed. you need to find the witch or wizard you offended and make amends.

i’m really amazed this would even happen, as cat prefer to bury their waste so they like places they can dig miles more than lawns. i wonder: did your u maybe see one cat, once, poop and now you think all poop is cat poop? because dogs are a lot more likely to be doing this regularly than cats.

All these psychopaths saying kill the cat or catch it and relocate it are fucking deranged. Talk to the owners if you know who it is... firstly, I'm sure they would at least be receptive to the problem and if they're not then maybe look into legal outlets. If you've gone out of your way to post on lemmy you're technically savvy enough to look up local laws. people have also posted actual remediation methods that aren't terrible and could actually improve your lawn in some scenarios as well so maybe try those out if you're into them.

I'm positive that no one wants to lose a pet in any capacity. Just some simple communication with the owners could solve this, and if not, there are other options.

Sorry you're going through this though, shit sucks. Pun intended.

Place a box with sand near the area you want to protect. Move it further away a feet or so by day. In 10 days that cat will be shitting wherever you guided it to. Leave the box and or the sand. Done.

Low cost. Low effort. No animal cruelty. No dealing with neighbor. Effective.

Go with it, not against it. Make a small sandbox. Cat would favour that as a toilet over anything else.

Are you sure it's cats?

Have you seen the cats pooping or just sniffing the poop?

Depends where you are, but foxes would be a more likely bet. Fox poop stinks too - really foul stuff. Cat poop generally is quite inocuos once it drys out, although a lawn mowing bot slicing it up would make sense for making it worse.

I have never heard of cats pooping in the middle of a lawn before. Normally they like private and safe spaces to poop as they're vulnerable when pooping, and normally they're fastidious about burying it where possible.

iF it really is cats, then maybe get a gravel section next to your lawn that they might prefer to go in? A litter box essentially.

Get a dog

Put in a sand pit somewhere you are ok with them shitting. Training domesticated cats is an undertaking that in my limited experience comes down to giving them an option they'd prefer over their current behavior. Trying to dissuade a feral cat from shitting where they please humanely seems like a loosing battle.

We bought a couple of plants that have a smell that allegedly repels cats and other animals and had good results planting them around our patches. But we also left the dog in the garden more often which might have helped even more. The plants are called plectranthus ornatus ... but there are others which might also work: https://horticulture.co.uk/cat-deterrent-plants/

motion detection water sprinkler?

• might be the most harmless and probably affordable

Easy. Get rid of the lawn. Animals live outside. If it's not this cat, it'll be something else.

Plant non toxic cat repellant plants:

https://pondinformer.com/plants-that-repel-cats/

Plant some lemongrass.

When that shows to only be partially effective, accept the fact that you can't control the ongoings of the world in every fashion.

I have a section of dirt next to my driveway. All the other suggestions here worked for a few days max, but the solution ended up being laying chickenwire fencing on the ground. Cats won't do that on ground they can't dig.

My parents used to have this problem with dogs (our neighbors loved to let them shit everywhere but their own yard) and had a great amount of success with lining the perimeter of the property with moth balls.

Find the owner and tell them the cat is shitting on your property. If they tell you to pound sand, call city/county animal control to see what your options are. Alternatively, pick the shit up before your robot lawnmower runs it over.