Harrows

Harrows are agricultural implements used to break up and smooth the surface of soil after plowing, to disrupt weed growth, and to incorporate crop residues. They can also be used to firm a seedbed and create a consistent tilth. Harrows operate by combing, cutting, or dragging the soil surface with attached tines, discs, or chains.

Several styles exist. Disc harrows employ rotating concave discs that cut and crumble clods and mix surface material as the machine is pulled. Tine or spike harrows use sets of metal teeth to comb the surface, uproot weeds, and roughen or level the soil. Spring-tooth and chain harrows are more flexible, with hinged or linked elements that break up clods and lightly till the surface. Chain harrows are commonly used for grooming pasture, seedbeds, or leveling uneven ground.

Use and operation: Harrows are typically drawn by tractors or draft animals and used after plowing or pasture renewal. The aggressiveness, depth, and speed depend on soil moisture, residue, and crop requirements. Overly aggressive harrowing in moist soil can cause compaction or clumping; in dry, hard soil it may not effectively loosen the surface. Proper adjustment is important to produce a uniform seedbed and to minimize weed disturbance.

History and context: Harrows have been in use for centuries, evolving from manual to powered forms. Today, they are common in mechanized agriculture and are chosen based on soil type, residue, and desired seedbed conditions.