According to the IRS: "You are in the business of farming if you cultivate, operate, or manage a farm for profit, either as owner or tenant. A farm includes livestock, dairy, poultry, fish, fruit, and truck farms. It also includes plantations, ranches, ranges, and orchards and groves."
The key word is "business". Or another way to say it is: you farm to make a profit and not just as a hobby.
You may then be entitled to the QBI deduction of up to 20 percent, subject to various limitations.
For additional information, you can review the Schedule F Instructions.