Crop stem cutting is an inevitable process in harvesting,
and it is a process that can result in mechanical failure.
Although it depends on the structure and strength of the
plant material, the epidermis is the outermost protective
tissue of stem structure. The epidermis cells of gramineal
Napier grass contain a large amount of silica, so its surface
is hard, which affects the stem cutting significantly. As the
stem is mostly fibrous matter, the length of harvest period
affects the fiber hardness and moisture content of the crop.
The fiber fracture is an important part of the shear failure
process (Persson, 1987).