Agronomic Row Crops
Cultivator Shields

1. Rolling Shield
Round disks made of heavy-gauge sheet metal, plastic or of actual notched disk-harrow blades rotate vertically on a hub next to the crop. Mounted as a pair over the row or split on the cultivator gang between the rows. They are often notched or pegged along the edge to assure positive rotation to help them roll over residue. Use of some over-the-row mounts may be limited by crop height.
See: Hattaway, Spray

diagram of rolling shields

2. Rotary (Hoe) Wheel Shield
Spinning wheel on walking arm protects crop from flowing soil and residue. The wheels aggressively uproot small weeds next to row or in the row - depending on setting - without penetrating deeply enough to damage crop roots.
Source: 105

Diagram of a Rotary (Hoe) Wheel Shield

3. Panel Shield
Flat metal pieces 10" to 24" tall and 2' to 3' long can handle high-volume residue and soil flow. Various mounts either over the row or between rows, usually on parallel linkage to follow soil contour.
Source: Widely available

diagram of a panel shield

4. Tent Shield
Smaller sizes of these U- or V-shaped cover-the-row shields allow soil to flow up and over their tops. Taller models are basically heavy-duty panel shields joined at the top for strength and durability. Up to 3' long, 3" to 8" wide and 6" to 30" tall.
Source: Widely available
Thompson, Muller, Spray

diagram of a tent shield