seeding plough

A seeding plough combines two operations into one pass: it opens a furrow in the soil and simultaneously deposits seed into that furrow at a controlled rate. The plough body cuts and turns the earth in the normal way, while a hopper mounted above or behind the ploughshare feeds seed downward through a delivery tube positioned at the furrow bottom. This eliminates a separate sowing operation and reduces the time between soil preparation and germination.

The hopper is typically gravity-fed, with seed flow regulated by an agitator mechanism or a rotating disc that meters seed onto a delivery chute. Early designs used simple adjustable gates; modern versions employ seed wheels with pockets or fluted rollers that grip individual seeds to ensure more uniform spacing. Depending on the crop and soil conditions, seed depth is usually set between 25 and 75 millimetres below the finished surface, controlled by the plough's working depth and the angle of the delivery tube.

Seeding ploughs work best in relatively clean, prepared ground. They perform well for cereals, pulses, and other row crops where broadcast or strip sowing is acceptable. Performance suffers in stony or sticky soils: stones jam the hopper agitator, and clay clogs the seed tubes. Very small seeds (like those of turnips or clovers) often hang up in the delivery mechanism, so farmers typically use seeding ploughs for medium to large seeds such as wheat, barley, peas, and beans.

Variants and trade-offs

Single-seed drills slot seeds individually into precise positions, offering finer control but requiring slower travel speeds and more complex mechanics. Seeding ploughs sacrifice that precision in exchange for speed and simplicity: they can work at 8 to 12 kilometres per hour, typical of general ploughing. Some designs incorporate a small roller or press wheel behind the seed tube to firm the soil around the seed. Others attach a harrow or crumbler to break clods and level the surface immediately after seeding.

The term itself reflects function: the plough does its historical job of soil inversion, while the seeding mechanism is bolted on as an ancillary feature. This arrangement made sense when farms could not justify separate machines for ploughing and drilling. Today, seeding ploughs are less common in intensive arable rotations but remain practical for smaller holdings, newly broken land, and situations where a single implement pass saves fuel and labour costs. Their main weakness is lack of accuracy in seed spacing and depth, which becomes critical for high-value crops or precision farming systems.