After you resolve the matter of the shipment of oranges, Gurcant has a farming task for you.
Requirements
This quest is only available if you started the game in Limsa Lominsa, you have completed the quest Double Dealing, and have reached level 9.
Starting the Quest
You can start the quest by talking to Gurcant at Summerford Farms in Middle La Noscea.
Speak with Rhotwyda
Rhotwyda will be marked on the map. She is just outside of an orchard west of Summerford Farms.
Obtain the Blackloam
The next quest destination is marked with an orange circle on the map. It's across the Agelyss River, so go north and cross the bridge, then go west. You'll see a hill between you and the orange circle on the map. Go to the west side of this hill to find an opening.
There are level 8 Wounded Aurochs in this area. They have a yellow/orange symbol next to their names, which means that they will attack you if you get too close. You need to check on the sparkles in this area, so either walk behind the Aurochs to try to sneak past, or try to fight them one at a time if you can't avoid them.
Check on the three sparkles in the area to get the three blackloam.
Take the Blackloam to Pfrewahl
The next quest destination is to the northeast, at a wooden building. Talk to Pfrewahl to deliver the blackloam.
Next Main Scenario Quest
After completing the quest, you can talk to Pfrewahl again to accept the next quest: Plowshares to Swords.