Is the word subject correct in this phrase?

[iodim]

The newspaper has an interesting subject about nature

[Mohammed Abu Risha]

I think you should say "topic" instead of "subject".

[Raymott]

The newspaper has an interesting subject about nature

"article" would be the most common term for this.

[colloquium]

Another alternative is piece.

Piece: something which has been created by an artist, musician or writer:
an orchestral/piano/instrumental piece
a skilful piece of work/research
Did you read that piece (= article) in the newspaper?

Cambridge Dictionaries Online - Cambridge University Press

However article, as Raymott suggested, is the most common (and specific) term.

I am not a teacher.