Farmers and Fishermen(p57)

If you are a farmer or fisherman, the following special rules for underpayment of estimated tax apply to you.

1. The penalty for underpaying your 2012 estimated tax will not apply if you file your return and pay all the tax due by March 1, 2013. If you are a fiscal year taxpayer, the penalty will not apply if you file your return and pay the tax due by the first day of the third month after the end of your tax year.
2. Any penalty you owe for underpaying your 2012 estimated tax will be figured from one payment due date, January 15, 2013.
3. The underpayment penalty for 2012 is figured on the difference between the amount of 2012 withholding plus estimated tax paid by the due date and the smaller of:
   1. 662/3% (rather than 90%) of your 2012 tax, or
   2. 100% of the tax shown on your 2011 return.

Even if these special rules apply to you, you will not owe the penalty if you meet either of the two conditions discussed under Exceptions.

See Who Must Pay Estimated Tax in chapter 2 for the definition of a farmer or fisherman who is eligible for these special rules.

Use Form 2210-F to figure any underpayment penalty. Do not attach it to your return unless you check a box in Part I. However, if none of the boxes apply to you and you owe a penalty, you do not need to attach Form 2210-F. Enter the amount from line 16 on Form 1040 line 77 and add the penalty to any balance due on your return or subtract it from your refund. Keep your filled-in Form 2210-F for your records.