For folks who tend food producing gardens, and who are also owned by cats, the following may be of intense interest.
People who garden without the assistance of felines may just want to look away at this point. This will also probably not be of any interest to people who are able to keep their cats indoors.
I have 2 cats, my neighbors on all 3 sides have a cat each and there are probably 3 or 4 cats from the neighborhood that visit regularly. So this means that my planted areas need to be protected from... ahem... unpleasantness. The reason is that feline feces may contain a parasitic disease called toxoplasmosis. It is transmitted by eating infected meat or by eating the feces of an infected animal. It can also be transmitted form mother to fetus, which is why pregnant women aren't supposed to clean cat litter boxes. Although it seems unlikely that one would ingest feces by scraping down the box, especially if you hold your breath, like I do.
Anyway, you can read lots more about toxoplasmosis if you like. For me, this is only 1 of the reasons I don't want cat feces in my garden.
Cats like to dig, and digging usually leads to, well, you know. I express my displeasure with this activity be shouting, clapping, scolding, cajoling, etc, all of which are only slightly and temporarily effective. I've been more successful with barriers.
Lots of chicken wire, which is great over bare dirt or seedlings. But once the plants start to grow through the wire you have to make a decision; either let the plants grow through it or remove it and find another barrier. Sometimes it's possible to place smaller pieces of wire around established plants.
Floating row cover works too, unless the animals find a way inside and then they just think you have made a tent for them to play camping in.
Since cats seldom respond to expressions of what you don't want them to do with anything other than more of the unwanted activity and defiant stares, I like to try to sell them something else. Enter the genius idea from my friend Martina, whom I consider a genius in many things besides feline lavatorial deterrence. Her idea is simple, ingeniously simple; provide a more inviting out door cat litter box than your garden. Et Voila.
It took a while before I got my first customer, but now I get at least 1 deposit per day, and that's 1 less poop in some other part of the garden. I have plans to make it even more inviting by filling it with sand and occasionally sprinkling catnip in it. Wish me luck.