How can be stopped cat to pooh in the garden?

Men's urine!

It doesn't always work, but the scent will sometimes stop cats from trying to claim the territory.

Hi Shan. There are some natural remedies that people use and they claim it work. I am including two websites that you should find useful. Please read through them carefully. One of them has multiple questions and answers about cats so you need to find the one that applies to your problem.

Keeping Cats Out Of The Garden (http://www.thefrugallife.com/catsout.html)

Questions On Cats (http://www.ext.nodak.edu/extnews/hortiscope/pests/cat.htm)

I hope you find this helpful. Good Luck!