How do you get brown concrete?

It's not surface dyed as far as I can tell.retaining wall. Is it in the aggregate color? Dye mixed?

As you can imagine I am being tasked with adding a section. Would like it to match.

It's not surface dyed as far as I can tell.retaining wall. Is it in the aggregate color? Dye mixed?

As you can imagine I am being tasked with adding a section. Would like it to match.