That looks to be a drain line and the part that is sticking out is called a cleanout. When the drain gets clogged you unscrew the cap and run a snake through the pipe to clear it.
All Blessings,
Bill
Bill, thanks for your response. Do you think starting a vegetable garden on this area can cause problem in future?
i was preparing my backyard for vegetable garden and found one pipe buried under. Can anyone help me identify what this is for? and can i make vegetable garden on this?
I have put the picture on below link
