@nern you have a client, a farmer, whose husband has died....

So, who was the farmer?  The deceased husband, or the living wife?

If the deceased husband was the farmer and he has been filing as a sole proprietorship on a Form 1040, Schedule F, it is possible [depending upon the state you are in] that he was the owner of 100% of the farm machinery and it gets a 100% step-up in basis.  If she is not the farmer and is the beneficiary and she sells all of the farm machinery soon after her farmer husband's death, there would be no gain. 

If she keeps the farm machinery for a period of time. say into the succeeding year, these items begin the depreciation cycle anew.  Enter all of the farm machinery items onto the wife's new Schedule F with an acquisition date of the DOD of her deceased husband.  

If the deceased husband was a sole proprietor cash basis farmer there is also a step-up in basis of the growing and stored grain and forage inventory, bedding, breeding livestock, feeder livestock, etc.  Real Estate. if in joint tenancy, would likely receive a 100% step-up in basis on the deceased farmer's 1/2 only.  The surviving wife's 1/2 would retain it's original basis.  This would also be the case of all farm real estate improvements [buildings, tile, etc]. Enter onto her new Schedule F as of DOD and depreciate anew.

You need to discuss this all with the estate attorney.  He is a legal expert for your state laws.