Bring 20 Un'Goro Soil samples to Ghede on the Elder Rise of Thunder Bluff.
The soil of Un'Goro Crater is reportedly enriched with potent magical qualities. The Cenarion Circle wants to study this soil in large quantities; go into the wilds of Un'Goro and acquire enough of it for our continued research.
The rich soil will stick out in piles from time to time, and some of the beasts might have usable samples on their being. Take them all outside to Ghede; just look for the piles of dirt and the tauren barking orders. He means well, just don't get him riled up though!