The IRS considers you to be in the business of farming if both of these apply:
Farm income includes:
You use Schedule F (not Schedule C) to figure the profit or loss of your farm.
You're usually self-employed if you operate your own farm on land you either own or rent. Since you're self-employed, you get Social Security coverage by:
Your farm income might fall below a certain level. If so, you can use an alternate method to figure self-employment tax.
Since it's difficult to predict farm income, the estimated tax rules are different for farmers.
To learn more, see Publication 225: Farmer's Tax Guide at www.irs.gov.