Agricultural Productivity

Between 1750 and 1901 the population of Britain rose from around 5.7 million to somewhere near 37.5 million. There therefore needed to be a considerable increase in agricultural productivity, before people could be taken off the land to become the workers of industrialisation. Historians posited a couple of agricultural revolutions, one some 12,000 years ago, in the neolithic age, and another between the 17th and 19th centuries. Whilst agricultural productivity was completely transformed, timewise it was exponential evolution, rather than revolution. Agricultural productivity was following the same exponential growth pattern as population and, later, industrialisation.

The neolithic change from hunter-gatherer to farmer was a patchy, on and off transition. Many of the early attempts to cultivate cereal plants were abandoned, probably because repeated planting of the same crop without fertiliser, rapidly leads to unproductive soil as essential elements are taken from the soil by the growing crop. Farming also provides a less nutritious diet, and the height of people declines as a result. So why give up hunting for farming? For some people, hunting had become more like gathering. They had learnt that waiting at a river crossing for migrating herds, or trapping migrating fish, could bring them all the protein they needed, so they became sedentary and could, therefore, accumulate wealth. A hunter-gatherer can only accumulate what he could carry. A pastoralist, only what his small cart, pony, or camel could carry. A man with a hut can just keep adding rooms to it and accumulate more junk. Diet became restricted mainly to a few cereals which can be stored. This table is taken from Luke Kemp’s book Goliath’s Curse.

In Britain, agricultural productivity is slowly driven up by enclosure, which creates bigger fields, crop rotation, which replaces nitrogen in the soil, and the introduction of better farming tools, such as the metal mouldboard for ploughs. As we saw in the introduction, cereal yields show a slow but steady increase from the 13th till the 18th centuries. The curve then starts to change shape as growth becomes exponential.

Enclosure

At the time of the Norman conquest, British agriculture was practiced using an open field system. The land was divided into small strips each of about an acre, worked independently from other strips. Enclosure changed this to large fields bordered by a hedge, fence, or wall. Enclosure was primarily driven by the wool trade. English wool was a desired item in Europe from the 13th through 15th centuries. It could be woven into a virtually waterproof cloth. There was a Roman reference to English wool being "as fine as spider's silk" and a later Italian reference to its fineness. For whatever reason, English wool was prized, and the wool trade blossomed. Sheep need large areas of grass that they can roam over, grazing as they go.

Crop Rotation

Planting the same crop repeatedly in a plot of land without adding fertiliser leads to soil degradation, as nutrients are leached out of the soil by the growing crop. One way to avoid this is by crop rotation. After the main cereal crop is harvested, then the plot can be left fallow, to allow regeneration from ploughed in weeds, or a crop such as clover can be sown which, when it is ploughed, will increase the nitrogen content of the soil. The most efficient crop rotation pattern is the Norfolk four field system. Wheat is followed by turnips, then by barley, and finally, by clover. This provides a main cereal crop, a root vegetable crop, for animal feed and a hedge against main crop failure, a secondary cereal crop for both human and animal consumption, and a crop to replace nutrients, when it is ploughed under.

Farming Tools

The two farming tools which made the most difference to agricultural productivity were the metal plough and the horse collar. Originally, ploughing had been done by dragging a wooden spade shaped blade through the soil, hauled by oxen. This created a groove but did not really disturb the soil very much. The curved plough blade, which both cuts the soil and then turns it over, brought new soil to the surface and buried weeds where their decomposition could replenish the plot. Oxen are not strong enough to pull a steel plough, but the oxen yoke, if used on a horse, would restrict its windpipe. The horse collar solves the problem. The collar rests on the horse’s shoulders and the animal's massively strong back legs propel it forward. Two horses can pull as much as six oxen.

Another Slow Evolution

There are two ways to measure agricultural productivity. Yield per area or yield per farm worker. It was the growth of the latter that freed workers from the farm to man the factories during industrialisation. It took some 800 years to reach the necessary level of agricultural productivity, even with the extra push given it by the Black Death in the 14th century. But, by the middle of the 18th century, we had enough people and enough agricultural productivity to move industrialisation up onto its exponential growth path.