The Spaniards then looked to agriculture to turn a profit and began growing sugar cane, which had been introduced to the Caribbean on Columbus's second journey.
Sugar cane was a profitable crop for the Spaniards. 
mnli hypothesis: Sugar cane was a profitable crop for the Spaniards.  premise: The Spaniards then looked to agriculture to turn a profit and began growing sugar cane, which had been introduced to the Caribbean on Columbus's second journey.