Geoscience Reference
In-Depth Information
the importance of soil texture to water movement and successful drainage. Clay tiles
were in common use by then, and infield or under-drainage made great progress, es-
pecially under the influence of Bailey Denton. In 1855 Denton made a country-wide
survey of drainage need, and concluded that nearly 15 million acres in England and
Wales could be improved. Modern estimates suggest that 12 million acres were in fact
drained by 1880, a little under half a million a year.
Twentieth century technology, and the scientific study of soils, opened the flood-
gates to experimentation and change in crop husbandry. Fertilizers were a major force
as they offered a release from the centuries-old necessity for rotational cropping as
the means of maintaining soil nutrients - though the early farmers would not have
thought of it in such terms. The need to maximize food production during and after
the second world war provided new stimulus to realize greater productivity from soils.
Machinery provided ever more agricultural muscle, tractors and combines first allow-
ing farmers to cultivate and harvest larger areas more quickly, and then requiring field
sizes to be enlarged to match their maw. The ploughing up of pastures once again, the
explosive growth of the pesticide industry, and the dramatic return to an almost pre-
enclosure landscape in eastern England, all followed in a few decades.
This very brief historical perspective brings us back to modern times. It provides
just the barest outline of the forces that have acted upon the agricultural soils of this
country, and we must now consider some of the factors in more detail. We will then
be better able to gauge whether the changes wrought by agricultural 'extensification'
in the future will involve anything truly novel, as far as the soil is concerned, or are
merely part of a longer cycle of changes which have been experienced before.
C ULTIVATION
Ploughing is one of the oldest agricultural operations and has altered relatively little
except in speed since medieval times. The ploughman's skill in turning a straight and
even furrow was tested in the annual ploughing competitions that formed a regular
feature of village life until recent times. How much more of a challenge this must
have been when the plough was drawn by oxen or horses, and when every plough was
hand-made.
Drilling seed into the soil, on the other hand, instead of broadcasting it, only
dates back to the 18th century - about the time that the first factory-made ploughs
were produced in Scotland. A simple drill was invented by Jethro Tull who also con-
ceived a theoretical basis for cultivation. In his Essay on the Principle of Tillage and
Vegetation in 1731, he put forward the idea that the sown plants competed with each
other and with weeds for nutrients in the soil. Cultivation, he thought, was beneficial
not only by reducing weeds but by increasing the 'pasture' upon which the roots of
Search WWH ::




Custom Search