So far I'm leaning towards a part of some 18th century "or later" farm equipment.. here is a device invented by Jethro Tull in the 1700's called the seed drill.
It planted seeds in rows much quicker than sewing by hand.
Two things about your piece hint at 19th century to me.
#1 the "blade" portion appears to be braised to the narrow portion.
#2 the threaded end on that narrow portion.
The blade is 2 1/4 wide and 7 inches long. The handle appears to be made from a carriage bolt a d nut. The other side of the nut curl is broken off. The Chief of the Yeopim tribe lived on this property and afterwards became a plantation in 1760.