A hay knife is an agricultural hand tool: a long-bladed knife which may have large rounded serrations on the edge, or a smooth edge used for sawing off sections at the end of a , stack or compact pile of hayor silage. In the England hay knives may have smooth edges. It was needed due to loose hay / silage being compacted in a stack. To remove it a hay knife is used to make a vertical cut so that sections can be removed easily as the intertwined stalks have been cut. The offset handle allows the user to work down a face. Once one section has been removed the worker starts again at the top creating another section to be removed