I think it just really depends upon where it was found. Used longer in the South I imagine as the North had the steel and factories with the exception being Birmingham ,Ala. I see it is in the what is it section. They are very good there on I,d's.
Back in the olde log cabin days, you may have needed to hang an item from the wall, and I believe that the flat (knife shaped) part was inserted into/between the logs. Thus you would be able to hang something from it, or there may have been another placed on an opposite wall, and a rope tied between the two for hanging/drying clothes on a rainy day.
Just a possible use for your item.
I'm gonna say farming implement as well, the blade was made with that twist to throw up the dirt or turn in over as it was dragged. A straight blade would have just cut into the ground.