You are most probably confusing the properties of Ferromagnetic Substances in relation with the Earth’s magnetic field.
And to be honest, I think the question isn’t that much clear in the sense.
Well, I’m answering to the query “Why doesn’t earth pull iron strongly as compared to other objects if it is considered as a big magnet?”.. if that is what you mean.
First of all lets start with Earth’s magnetism:
Factually, the strength of the field at the Earth’s surface ranges from less than 30 microteslas (0.3 gauss) in an area including most of South America and South Africa to over 60 microteslas (0.6 gauss) around the magnetic poles in northern Canada and south of Australia, and in part of Siberia. (source – Wikipedia)
And a small bar magnet has a magnetic field of 0.01 Tesla !!
See the stark difference?
I think this much is self explanatory.. but if you still haven’t got it.. let me elaborate a bit.
Its true that earth has a magnetic field and we find its application in finding the direction through a compass.. but it isn’t that much strong to pull iron to the core tearing down the ground.
Also, Gravitation is a separate thing which is universal so don’t put it here just because it is about attraction.
If anyone finds something wrong in my answer then please mention it.
Hopefully now you have got it.