Bonanza farms were farms were huge farms in the western United States. In the late 1800's, companies and the wealthy bought thousands of acres and established wheat farms. they hired people to work the land for them, much like a factory.
Since they could produce large quantities of wheat, it drove down the price of the product. Small farmers couldn't compete with the lower price point. They were not making enough money from their crops, if they had to sell them at the lowered cost set by the bonanza farmers.