Technically, you don't really need any, but you'll probably have more luck if you major in English in college or some such thing. It also depends what you want to write for.
you need to know how to rhyme....
To be a true writer you can choose to get degrees and go to college and all of that or you can be an ordinary person who actually doesn't have a college education. It is easier to be a writer with a lot of education, but it's nor really required. Pretty much anyone can write a book, but not everyone can write a good book.
how much education is needed to become a engineering psychologist
alot
alot.
about a high school education
What kind of education do you need to become a cartographers need?
lots
4 year degree in college
Answering "How much training do you need to be a song writer?"
You don't need any education to become a writer, but it helps. Since many writers end up teaching at colleges and universities then you'll probably need a B.A., M.F.A., and Phd. in English, all of which will take a total of ten years in college. If you are heavily published by the time you get your M.F.A. (this isn't the norm, but it could happen) then you might not need that Phd., which would save you three years.
You don't need training just creativity, you must obviously know how to write and use punctuality.