Dirt: The Erosion of Civilizations - Kootenay Local Agricultural Society

104
Despite such profiteering, by 1868 almost two hundred thousand acres of
the High Alps had been replanted with trees or restored to meadow.
Touring southern France before the Second World War, Walter Lowdermilk
found intensive farming practiced on both steep slopes and valley
floors. Some farmers maintained hillslope terraces like those built by the
ancient Phoenicians. Lowdermilk marveled over how in eastern France,
where terracing was uncommon, farmers would collect soil from the lowest
furrow on a field, load it into a cart, haul it back up the slope, and dump
it into the uppermost furrow. Centuries ago when this practice began,
peasant farmers knew that they had upset the balance between soil production
and erosion, and that people living on the land would inherit the
consequences. They probably did not appreciate how far they were ahead
of Europe’s gentlemen scientists in understanding the nature of soils.
At the May 5, 1887, meeting of the Edinburgh Geological Society, vice
president James Melvin read from an unpublished manuscript by James
Hutton, the Scottish founder of modern geology. The rediscovered work
revealed the formative geologic insights Hutton had gained from farming
the land, observing and thinking about relationships among vegetation,
soil, and the underlying rocks. In particular, Melvin appreciated the parallels
between Hutton’s century-old musings and Darwin’s newly published
book on worms.
Hutton saw soil as the source of all life where worms mix dead animals
with fallen leaves and mineral soil to build fertility. He thought that hillslope
soils came from the underlying rock, whereas valley bottom soils
developed on dirt reworked from somewhere upstream. Soil was a mix of
broken rock from below and organic matter from above, producing dirt
unique to each pairing of rocks and plant communities. Forests generally
produced fine soils. “[A forest] maintains a multitude of animals which die
and are returned to the soil; secondly, it sheds an annual crop of leaves,
which contribute in some measure to the fertility of the soil; and lastly, the
soil thus enriched with animal and vegetable bodies feeds the worms ...
which penetrate the soil, and introduce fertility as they multiply.” 12 Anticipating
Darwin in recognizing the role of worms in maintaining soil fertility,
Hutton also understood the role of vegetation in establishing soil characteristics.
The visionary geologist saw soil as the living bridge between rock
and life maintained by returning organic matter to the soil.
At the close of the eighteenth century—long before Melvin rediscovered
Hutton’s lost manuscript—Hutton argued with Swiss émigré Jean André
de Luc over the role of erosion in shaping landscapes. De Luc held that ero-
let them eat colonies