Hm.. unsure. I think it depends on how much they know about each other's weaknesses.
Terra has the ability to lift rocks into the air with her on them- therefore, she would be out of Toph's ability to see. That would be a major disadvantage, but Toph still has strong hearing abilities.
If Terra stayed on the ground, however, I have a strong feeling that Toph would dominate. Non-only could Toph see where she was, but she could detect if she's lying, and her behavior and feelings (like if she's getting nervous.)
Although, Toph can get really irritable, and just like Terra defeated Raven, she could work at Toph's anger. Terra is troubled, however, and Toph could use that to her advantage as well por pointing out Terra's mistakes and making her feel out of control again. ..Also, Toph can bend metal- therefore, she can create an armor for herself and use harder elements against Terra.
It's all depending.. I think they both stand a good chance against each other.
..And for those who don't know who Toph is, here's her picture.
