Some have down pressure features to increase the action and control bounce of the harrow frame. Heavy harrows can also satisfy the incorporation requirements of some herbicides. Power requirements are usually 200 hp and up. Oscillating harrows, although no longer common, often provide the best action for spreading evenly settled straw, but warm, dry conditions are important for efficient equipment operation. The aggressive action of these harrows makes shallow incorporation of granular herbicides possible.
Rotary harrows are ideal for shallow incorporation of herbicides into the soil.
These harrows rarely plug up and they leave the residue on the soil surface. However, they do not spread straw. Take care not to harrow too much because the loose straw left on the surface may be blown away by strong winds. Power requirements for both are relatively high, but they produce a more uniform residue cover. A balance is needed between standing stubble and chopped residue on the surface.