Why Did Scattering Seed by Hand Waste Most of It? Put It in the Ground

Sowing by hand meant walking across a prepared field throwing seed in an arc, which distributes it unevenly by nature, and then harrowing to cover some of it. A large share was simply lost, being eaten by birds, left on the surface to dry out, buried too deeply to emerge, or landing where another seed had already landed. Estimates of the waste vary and are substantial in every account. Plants came up at random spacings, so some crowded each other while ground elsewhere stayed bare, and there was no possibility of working between them because there were no rows. The method had been essentially unchanged for several thousand years.

The operations are simple and doing all of them in one pass is the point:

• •A coulter or disc opens a narrow furrow at a controlled depth
• •A metering mechanism releases seed at a set rate rather than in a stream
• •A tube delivers the seed into the furrow rather than onto the surface
• •A following device closes the furrow over the seed
• •Several units work side by side at a fixed spacing, producing rows
• •Depth and rate are adjustable for different crops and conditions

Jethro Tull is credited in English accounts with inventing it around 1701, and the attribution needs qualifying in both directions. Machines for placing seed in furrows were used in Mesopotamia several thousand years earlier and are depicted on seals. Chinese multi-tube versions were in widespread use from around the second century BC and are far closer to the modern machine than anything in Europe at the time. Italian designs were described in the sixteenth century. What Tull contributed was a practical horse-drawn machine with a reliable metering mechanism, publicity through a widely read book, and a strong association with sowing in rows so that the ground between could be worked, which was the part that mattered most.

A machine saving most of the seed should have been adopted immediately and it was not, taking well over a century to become general in Britain, and the reasons are instructive about technology generally. Early machines were expensive, broke frequently and needed a skilled operator to keep the metering working, so a farm buying one gained nothing if it stood idle. They worked poorly on heavy, stony or uneven ground, which described a great deal of farmland. Seed was cheap relative to labour in many places, so the saving was not the decisive argument. Labourers resisted machinery that reduced employment, sometimes violently. And the benefit depended on also adopting row cultivation and horse hoeing, which meant changing the whole system rather than one operation.

Placing plants in straight evenly spaced lines changed far more than seed consumption. Weeding between rows becomes possible with a horse-drawn hoe rather than by hand, which was the labour bottleneck in arable farming and which Tull promoted as vigorously as the drill itself. Fertiliser can be placed where the plants are rather than spread everywhere. Crops can be inspected and treated selectively. Harvesting machinery, when it arrived a century and a half later, requires plants in known positions and would have been impossible otherwise. Modern practice has extended the principle to placing individual seeds at recorded satellite positions, so that every subsequent operation can be directed to the exact plant.

Broadcasting by hand lost a large share of the seed to birds, drying, burial and crowding, and produced no rows. A machine opening a furrow, metering seed into it and covering it saved the seed and placed plants at known spacings. Mesopotamian and Chinese versions long predate the English attribution to Tull, whose real contribution was a practical machine and the promotion of row cultivation.