If the dinosaurs were really large once was the earth more fertile then?

Answer 1

Not necessarily. The Earth may have been more fertile back then (there is a lot of organic material buried in the ground now, the solar system does change its position in the galaxy over the millenia, and the earth continues to slow its rotation, etc.)

But the size of the dinosaurs probably had little to do with the fertility of the soil. It had more to do with the evolutionary advantages of being bigger than your brothers and sisters or your prey or preditors.

On the Galapogos Islands, many bloodlines of animals are much larger than their mainland counterparts just because of the ecological differences in preditor-prey relationships. It has little to do with the fertility or infertility of the soil.

Answer 2

There was more carbon dioxide in the atmosphere which resulted in plants being much larger than they are now. This resulted in much larger herbivores and so the carnivores needed to be much larger to eat them.
As carbon dioxide levels reduced, the size of plants was reduced and so smaller herbivores had an advantage etc etc.

Answer 3

maybe you mean more nutriment for the earth ,right? , but now the earth is longer in time collecting or digest some ore in it too

Answer 4

I'D SAY DINOSAURS WERE JUST GOD PRACTICING.