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pattern that was created, known as ridge and furrow, is generally associated
with mediaeval practice, but in fact the method was employed well into the
nineteenth century, by which time other means of drainage were becoming
available.
Soil drainage
Originally designed to turn the soil before seed bed preparation, the plough
has several other forms. Improvements in drainage can be achieved with a
conventional plough (see above), but also by creating a ditch with a plough
which has two mirror-image mouldboards attached side by side. In the early
nineteenth century a highly specialized plough was developed specifically for
draining clay soil. Clay, being plastic, can be moulded, and if a solid cylinder is
passed through it, a hollow tube will be formed which will retain its shape for
a considerable period, acting as a drain for excess soil water.
The mole plough, as it was christened, gained particular significance
because John Fowler, an engineer from Leeds in Yorkshire, began to
experiment with steam traction engines and winches to provide the power for
this work. By the 1850s he had developed a two-engine system which was to
provide a comparatively cheap and fast method of drainage, with the result
that hundreds of acres of cold wet land in Britain and elsewhere were brought
into productive use. Extending the idea further, he devised a system whereby
the mole would drag behind it a string of clay pipes, thus creating an instant
and durable drainage system. Although the materials may have changed,
plastic tubes replacing clay pipes, much of modern drainage is achieved in the
same way. Fowler took the process a stage further by creating a conventional
reversible plough with six furrows a side, which could then be pulled
backwards and forwards across the field, turning the soil at each pass.
Although these machines never ploughed huge acreages, part of the
significance of Fowler’s achievement was that his were the first successful
attempts to apply mechanical power to field operations.

SOWING
To maximize the yields from a given area of land, it is necessary to sow the
seeds as evenly as possible, so that each developing plant will have its own
source of nutrient without competition from its neighbours. It is also
necessary that the seeds are placed at a particular depth, so that the young
seedlings can establish themselves before emerging from the soil, but not so
deep that the nutrient reserves in the seed are used up before the new leaves
are able to start photosynthesizing. An even depth of seed will ensure an
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even growth throughout the crop, and this in turn will result in the crops
reaching maturity simultaneously. Any variation from these optimum
spacings will result in a fall in yield.
The easiest way to spread seed on to a prepared area of land is to broadcast
it. This method involves taking handfuls of seed and hurling them out in an
attempt to cover a given area as evenly as possible. After broadcasting the land
will be harrowed so as to cover the seed, and therefore make it less available to
birds and other pests. A major disadvantage of broadcasting is that it leaves
seeds randomly distributed, and it is therefore impossible to weed between the
plants. Whatever the skill of the broadcaster, the sowing will only be an
attempt at the optimum and will never achieve it, and almost since seeds have
been sown, methods have been sought for a mechanical means to regulate
depth and spacing.
The earliest known information concerning the design of a seed drill is to
be found in the pictorial representations carved on Sumerian seals dating to the
third millennium BC. These implements resembled the ard used in the area,
except that attached to the handle was a funnel and tube passing down behind
those parts which moved the soil. The seed was dropped into the funnel, and
was then deposited at an even depth and in as straight a line as the ploughman
was able to achieve. A similar device still exists in India, and indeed it was

noticed and commented upon by European travellers as early as the eighteenth
century. Despite various attempts to design a machine in Europe, it was not
until the late nineteenth century that the drill became a standard part of farm
equipment. This does not mean that the drilling of seed in rows was not
practised, but rather that it was achieved by other means. One method was to
broadcast seed immediately after ploughing, and then to cultivate the ground.
In this way the seed tended to roll down the steep sides of the furrow slice and
thus formed a row along the furrow bottom. This method may have created
straight rows, and may even have placed the seed at an even depth, but it was
still an expensive practice as far as the seed itself was concerned.
An alternative method was to use a stick to make holes at a set spacing and
at a set depth, and then to drop seeds into them by hand. Again this would
have produced the desired result, but this time the cost was in terms of labour.
By the third century BC the concept of sowing crops in rows was already well
established in China. This was accomplished either by sprinkling seed along a
ridge, or else the seeds could be individually planted by hand. The latter was
used in dry land corn farming and also for wet land rice production. A further
refinement to individual planting is that of transplanting, which although
generally associated with rice can also be applied to other crops. The earliest
references to this occur in literature dating to the second century AD. The
process is not only extremely efficient in terms of land productivity, but also
increases the yield from individual plants. It is utilized in highly intensive
enterprises such as market gardening and horticulture.
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FERTILIZERS
Since animal and plant exploitation have always been closely linked, it is
reasonable to suppose that the earliest agriculturalists noticed, if they did not
understand, the boost to plant growth that could be derived from animal
manure. Similarly the early farmers who were dependent on seasonal river

flooding to provide soil moisture, would also have been aware of the fertilizing
properties of the silt contained in that water. Human manure was also known
for its fertilizing properties, and while its use tends to be associated with Far
Eastern farming, its value was well recognized in Europe, and it continued to
be used as a fertilizer well into the twentieth century, passing under the title of
‘night soil’.
Another practice with a long ancestry and wide distribution is that of green
manuring, whereby growing plants are ploughed back into the soil, and then
allowed to decompose. The plants ploughed in may be the weeds established
after harvest, or they may have been specifically sown for the purpose. The
Romans and Greeks favoured the use of legumes, recognizing their high
nitrogen content centuries before its existence was established, or the reasons
for its presence in these plants was understood.
Most of what society has viewed as waste has found its way on to the land
at one time or another. Animal and human manure have been joined by blood,
bone, rags and sundry other materials which were thought to be of benefit to
the soil. There was certainly an amount of artificially manufactured material
that joined this, though the references to it are limited. In a curious
premonition of future developments, the German chemist J.R.Glauber
suggested in 1648 that the methods used to produce the chemicals necessary
for the manufacture of gunpowder during the Thirty Years War should be put
to use for the benefit of agriculture.
For the most part the benefit of a particular material has been observed and
acted on, but scientific experiment was not part of the process, though the use
of trial plots was mentioned in Blith’s The English Improver, published in 1652.
Just how little the processes involved in plant nutrition were understood is well
illustrated in Jethro Tull’s The New Horse-Hoeing Husbandry, first published in
1731, which advocated frequent hoeing between the crop plants in the
mistaken belief that it would release nutrients from the soil. It was for this
reason that he advocated drill husbandry, rather than the reason for which it

was subsequently adopted, which was as a method of weed control.
By 1807 the chemist who had been appointed by the Bath and West Society
was offering soil analysis to farmers, utilizing a system devised by Humphry
Davy. In 1835 the first imports of guano arrived in Britain, and at about the
same time the first imports of nitrate of soda arrived from Chile. In the early
years of the nineteenth century coprolites found in Suffolk were being used in
the manufacture of superphosphates. The German chemist Justus von Liebig,
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published his discovery of a method for producing an artificial phosphate
manure in 1840. John Bennet Lawes is said to have discovered the same
method in 1839, but did not patent it until 1842. However with the profits
derived from this process he bought land and a house at Rothamsted in
Hertfordshire, where he was joined in 1843 by Joseph Gilbert. Together they
set up field experiments and laboratories and produced a standard of
experimentation which established Rothamsted as one of the major research
institutes engaged in soil research, a reputation it still holds today.
Sulphate and nitrate salts of ammonia were generated as by-products of the
manufacture of coal gas, and these were utilized as a rich source of nitrogen
fertilizer. However as early as 1898 the British Association was warning that
mass starvation would be caused by a lack of nitrogen fertilizers brought about
by the depletion of natural nitrate resources. At about the same time it was
discovered that atmospheric nitrogen and hydrogen could be made to react to
form ammonia, and in 1913 the chemical idea conceived by Fritz Haber was
being used, in the industrial process devised by Carl Bosch, to produce the gas
in quantity (see p. 223–4). The ammonia was used both for the manufacture
of explosives and also for fertilizer, thus finally realizing the suggestion made
by Glauber three centuries before.
Liquid fertilizers, in the form of town sewage or farmyard effluent, have
long been used and recognized as a source of fertilizer, and less obvious by-

products of manufacturing industry have been used on the land, such as the
ammonia solutions derived from gasworks. However the impurities contained
in such by-products, and the general bulk and difficulty in handling, precluded
the extensive use of liquid fertilizer until the 1950s. The production of highly
concentrated liquids such as urea and ammonium nitrate, and a better
understanding of the effects of application rates, have now made it an efficient
method in which to make the chemicals available to the crop plant.
The growing understanding of the plant nutrition cycle that was occurring
in the mid-nineteenth century was matched by a similar increase in the study
and understanding of the chemical and physical properties of the soil itself.
Some of the earliest work took place in the United States, as a result of which
the first soil map was produced in 1860, based on a survey of Maryland. The
careful study of soil and the matching of chemical application to the
requirements revealed by this study, is now an essential part of the process of
maximizing production from the land.
PEST CONTROL
It would have been obvious to both the early farmers and the contemporary
gatherers of wild plants, that if something ate or damaged the plants which
they themselves valued, then the returns they could expect from their labours
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would be reduced, whether the unwelcome intruder had been an elephant or
an aphid. The larger pests could partly be controlled by fencing, and evidence
for this appears quite early in the archaeological record. Insect damage, and
that caused by fungal parasites, is less easy to control, but would have been no
less apparent.
In the natural world there is a wide diversity of plants and animals living in
a state of approximate stability one with the other. This diversity is achieved by
the often very limited environment that any one species will tolerate, and this
will apply whether the relationship of species is of mutual benefit, of rivalry or

is parasitic. Agriculture reduces this diversity, and therefore reduces the land’s
ability to withstand environmental changes without significant effect on the
human economy. A plant species normally found scattered over a wide area is
more difficult to harvest than one which is cultivated in a defined location.
Unfortunately, it is also much easier for other species whose existence is
detrimental to that crop, to spread within it when it is sown to the farmer’s best
advantage.
There are a number of ways in which plant pests can be eliminated, or at
least their damage limited. Chemical control is the most commonly used in
western agriculture, and although there is evidence even in classical times for
its use, its true significance is very recent. The first method of control used by
the early farmer was the attempt to limit the availability of the crop to its pests,
whilst trying to maximize it to their own use. This could be achieved by
practising a swidden, or slash and burn, regime, so that a given area of land
would be exploited on a monocultural basis for only a short period and was
then left to revert to its natural state. In this way the crop pests were not given
long enough to build up their population to an extent that was potentially
dangerous to the farmer. However, where the human population was too large
to allow this continual movement from one piece of virgin land to the next, a
different approach was necessary.
Chemical control of pests was initially limited to substances that could be
derived from natural sources, such as plants themselves. Certainly used in
classical times, it was not until the mid-eighteenth century that experimentation
led to an understanding of the principles involved. Early workers in France,
recognizing that the tobacco plant was toxic to aphids, initially used the
ground-up plant as an insecticide. Later it was recognized that the chemical
nicotine contained in the plant was the responsible agent, and this knowledge
led to the identification of a number of other useful plant derivatives which
could be used in the same way.
Of the chemicals used for insect control one of the most significant was

dichlorodiphenyltrichloroethane, isolated in 1939 by the German chemist Paul
Müller. Though DDT has now passed out of use because of its more recently
discovered and damaging effects within the food chain, its use in the control of
insects which act as carriers of disease in domestic and agricultural animals,
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but more particularly in the control of the carriers of human diseases such as
malaria, had a profound effect in many regions of the world. This has not only
been to improve the health of those populations living in affected areas, but has
also allowed the settlement and exploitation of land previously unusable
because of the insect pests within it.
One of the earliest documented successes against fungal attack also
occurred in France, when in the 1840s a mixture of sulphur and lime was
found to be an effective agent against a powdery mildew which attacked grape
vines. Thirty years later lime was to appear with copper sulphate in a mixture
which effectively controlled the fungus which caused potato blight. This
particular combination, known as Bordeaux mixture, had originally been used
to spray on plants at the edge of vineyards in the hope that the violent colour
would put off prospective pilferers. Its fungicidal properties were recognized
when it was noticed that the crops at the edge were healthier than those deeper
into the vineyard which had been affected by downy mildew.
Although chemical pesticides are economically the most important,
biological control can sometimes be more effective. In 1762, Indian mynah
birds were introduced into Mauritius in a successful attempt to control the red
locust, the first of many examples in which a pest in one country has been
controlled by the introduction of a potential predator from another. One of the
major successes of this method was the introduction of a South American
caterpillar into Australia to control the prickly pear cactus. It has been claimed
that up to 25 million acres of previously unusable land was reclaimed in this
way. While there are great advantages in this method the dangers of a poorly

researched project are all too apparent, and it is inevitable that there have also
been disasters. Another type of biological manipulation that has been used in
recent years has been the introduction of sexually sterile insects into an insect
population in order to reduce, if not completely check, its breeding. There is a
political advantage to be gained from the application of pest control schemes
which have the appearance of being natural, but in fact any attempt to
eradicate a particular plant or animal species will alter the ecological balance
and therefore carries with it the dangers of unexpected and often spectacular
side effects.
WEED CONTROL
One of the essential differences between an agricultural economy and one
based on the collection of wild plants is that the former is dependent on the
successful harvest of a very limited number of plant species. Any unwanted
plants that grow within the crop are a threat to the nutrient supply of that crop,
and by the nature of things weeds were often more suited to the newly
prepared ground than were the crops themselves. The practice of fallowing,
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that is, leaving land free from crop exploitation every alternate or third year,
was partly because of the need to re-establish fertility after a crop, but it was
also used to attack any build-up of weeds. Fallowing did not mean that land
was left unattended, but was in fact a period when the land was continuously
ploughed and cultivated so as to create an ideal environment for the weeds to
germinate and develop slightly, before being destroyed by the next cultivation.
In this way the number of weed seeds remaining in the ground when the crop
was sown would be much reduced.
Fallowing will serve to limit the build-up of a weed population, but it will
also limit the time in which a piece of land is in productive use. An
alternative would be to choose a crop which will smother the seedling weeds,
while also being of value to the farmer, and alternating this crop with those

which were necessary for survival, but which created conditions suitable for
the establishment of weed populations. For example the thick, spreading top
of turnip will cover anything which germinates at the same time, and if the
crop is then fed to livestock by fencing them on to a small area each day, the
tight pressure of hooves will further clean the land. By introducing the turnip
into a rotation, a check on weed plant intruders can also be controlled
mechanically, by weeding, and this very labour-intensive method was all that
was available to most farmers in the past, and is still utilized within many
present economies.
Chemicals will also kill plants, but to be of any use to the farmer they must
kill only those plants which are unwanted. Early experiments on weed control
made use of the fact that the major crop plants were grass derivatives, and
therefore had long narrow leaves, while the major weeds were broad-leaved. If
a chemical mixed in water is poured on to the former it tends to run straight
off, but on the latter it will form into droplets on the hollows and angles of the
leaf, and therefore remain in contact long enough to do damage. Experimental
work in France at the end of the nineteenth century identified iron and copper
sulphates and nitrates as suitable chemicals for use with cereals.
Since the end of the Second World War the research and application of
herbicides has relied less on mechanical selectivity and more on the differences
in chemical and particularly hormonal activities which occur in different plants
at different stages of their development. The earlier complicated chemicals,
which have become known by their abbreviations such as 2,4-D or 2,4,5-T,
have now given way to a whole cocktail of chemicals which are available to
farmers. These chemicals have become vital to the achievement of high yields
from continuously cropped land, and with a reliance on single species
enterprises. A new move in chemical control is to utilize natural amino acids
found in plants to exaggerate processes that take place naturally. By the careful
selection of the correct amino acid for a specific weed, it is hoped that a new
generation of herbicide will be developed which will be environmentally safer

than those in present use.
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CROP ROTATION
A single crop grown repeatedly on the same area of land allows the expensive
back-up facilities of capital and machinery to be spread over a number of
years, but does raise problems of loss of fertility or build-up of pests. This
singleminded approach can be tempered by the use of a sequence of enterprises
which are mutually beneficial.
A rotation is devised to suit a particular set of circumstances and
requirements. At its simplest it is to be seen in the slash and burn technique. As
simple, but more productive, is the system known as alternate husbandry, in
which an area of land is used for a short time for arable production, and then
sown to grass and grazed for a number of years, the animal manure making a
significant contribution to the fertility of the land. There is increasing evidence
for the practice of crop rotations even in the very earliest settlement areas, but
the first references to alternate husbandry appear in the agricultural writings of
Columella in the first century AD. It was later practised by the Cistercians in
France, where as early as 1400 they were advocating five years of grass,
followed by two years of corn and then reseeding with grass.
More complicated rotations were created to resolve more difficult problems
and in Europe all the traditional constituents of rotations were known and
being used at least as early as the Roman period. Legumes, turnips and corn
were all documented if not widely grown. In mediaeval East Anglia extremely
complicated rotations of fourteen-year duration have been recorded. It
therefore seems likely that formal rotations were in use over a much wider
area, and at a much earlier period than the seventeenth-century English writers
would suggest. By 1880 leguminous crops were an established part of the
farming regime throughout Europe, and they represented a significant
proportion of the total arable acreage. This situation is significantly different

from that of a hundred years earlier and is an indication of the recognition of
the nitrogen fixing properties of this crop. Over the same period the reduction
in the acreage left fallow is significant and highlights the benefits derived from
the change of rotation made possible by the additional use of legumes, not only
in terms of increased yield per acre, but also in terms of the increase in the
numbers of productive acres.
HARVESTING
Reaping and binding
By the careful preparation of the land, and the attention paid to the plant from
germination to maturity, the farmer will come to harvest, which is perhaps the
most critical stage of all. One of the most common finds in an archaeological
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context is that of microlithic flint blades which are thought to have been used
in the construction of sickles. These thin, sharp pieces of flint were mounted
into a handle and fixed with pitch or similar material. They occur with early
Ubaid pottery at Eridu, in Iraq, and have been dated to the sixth millennium
BC. In these cases the handle and blade holder is made of clay, the blades
being made up from a series of small flakes of carefully prepared flint. The
presence of these flints, or the complete sickles themselves, is frequently cited
as one of the vital pieces of evidence for the transition from the hunter gatherer
economy to an agricultural one, together with pottery and grinding stones
forming the traditional agricultural package, but in fact each could also have
been of value to the gatherer. Under the microscope these flint blades
frequently show a particular gloss which is certainly of plant origin, but may as
easily have been caused by the cutting of grass or reeds for roofing materials as
by the cutting of corn stems, and therefore their presence on a prehistoric site
should not be seen as automatic proof of a sedentary farming existence.
The wild cereal species are very brittle just below the ear, and recent
experiments have shown that it might be easier to pick this corn by hand,

rather than cutting it with the primitive sickle; ethnographic evidence
suggests that in light sandy soil it may have been harvested merely by
uprooting. Less fragile strains were to be developed as domestication and
selection occurred, and a cutting blade became more necessary for the
harvest. The flint sickle gave way to one made of bronze, and then of iron.
Examples of this implement in use can be seen in the Egyptian wall
paintings, and later still in Roman mosaics. Innumerable examples have also
been discovered in archaeological sites.
Mosaics and actual examples also provide evidence for the existence of the
scythe by at least the Roman period, but there is no indication that it was
used on corn. The scythe consists of a blade of about a metre (3ft) in length,
attached to a long handle which allows for its use in a more upright posture
than is possible with the sickle. It is potentially a more effective tool for
harvesting corn than the sickle but, in Europe at least, their widespread use
seems to have been restricted to the cutting of grass until the nineteenth
century. However in China by the Han period, between 200 BC and AD
220, an implement was in use which should perhaps be called a scythe,
although its form differed considerably from the European equivalent.
Resembling an upturned walking stick, it has remained an essential harvest
tool to the present day.
The earliest application of the scythe to corn in Europe is of unclear date.
To gain the full advantage from the long blade it is necessary to attach a basket
or cradle to the handle. This cradle will collect all the corn cut in one sweep,
and allow it to be deposited out of the way of the next sweep, and conveniently
placed for the workers following, whose job it was to bind the corn into
convenient sheaves. The earliest representation of a scythe and cradle is in a
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thirteenth-century illustration, and it is also to be seen in Brueghel’s Spring,
dated to 1565.

The sickle was slower to use than the scythe, but it was much cheaper and
could be afforded by the harvest labourer. The more expensive scythe was
generally purchased by the farmer, and it has been suggested that this situation
changed the status of the harvester from one in which he was essentially a
contractor, to one in which he became purely a hireling, and that this produced
a resistance to its introduction in certain parts of Britain. Even today, in those
parts of the world where the corn is cut by hand tool rather than by machine,
there is great variety in the distribution of the two types of implement.
Speed is a necessity of the harvest more than any other aspect of the
farming year. A mechanical means to bring in the corn has therefore been a
matter of interest for centuries. The earliest references to a successful device
can be found in the first century AD writings of Pliny, and also those of
Palladius about three centuries later. Both authors referred to a harvester
which was supposed to have been used in northern France at the time in which
they were both writing. The machine consisted of a two-wheeled barrow, along
the front edge of which was a metal comb. When it was pushed into the
standing corn, the stalks passed between the teeth, and the ears of corn were
plucked off and fell back into the container. Until quite recently this
description was thought to have been fanciful, or at least describing an oddity
without very much practical use. However in recent years four stone relief
carvings have been found or identified which carry a clear representation of
the device that the writers had been describing.
No further evidence for this machine or any developments from it exists.
However, centuries later on the other side of the world something based on a
similar line was to appear. Whether John Wrathall Bull read the classics or had
a knowledge of the Roman texts is unclear, but in 1843 he submitted a model
of a harvesting machine to the Adelaide Corn Exchange Committee in the
hope of winning a prize being offered for a harvester suited to Australian
needs. Sad to relate, neither Bull nor any of the other competitors won the
prize, but a miller and farmer by the name of John Ridley saw the model and

built himself a fullscale example based on the same principles. Having proved
to himself that the idea worked, he took out patents and began production.
This basic design was continuously improved, and in 1885 the stripper-
harvester was produced (see Figure 16.1). This machine was capable of
harvesting, threshing and winnowing the corn in one operation. It has been
suggested that this Australian invention had such an effect on binder sales in
the Australian, Argentine and American markets that the two major
manufacturers, International Harvester and Massey Harris, were forced into
combine harvester production. By 1909 the first self-propelled example had
been built, using an internal combustion engine, though it was not to become a
production reality until twenty years later.