Dirt: The Erosion of Civilizations - Kootenay Local Agricultural Society

As agriculture spread north and west, people opened the first clearings
in Europe’s ancient forest to cultivate small plots for a few years at a time.
Ash from burned vegetation fertilized newly cleared fields, helping to
maintain initial crop yields until soil fertility declined enough to make it
worth the hassle of moving on. The practice of abandoning worn-out fields
periodically left fallow land to revegetate, first with grasses, then shrubs,
and eventually back to forest. Ground cultivated for a few years then lay
fallow for decades as the recolonizing forest gradually revived the soil,
allowing clearing and planting again decades later.
Lake sediments, floodplain deposits, and soils record the postglacial
evolution of the European landscape. From 7000 to 5500 bc stable environmental
conditions left little evidence of human impact. Pollen preserved
in lakebeds shows that Neolithic farmers opened clearings in dense
forest as agriculture spread north from the Balkans. Cereal pollen shows
up in soil profiles and sediment cores about 5500 bc in central Europe.
Sediment cores from lakes provide the first incontrovertible evidence of
substantial human impact on the central European landscape as massive
amounts of charcoal and increased sedimentation—evidence for accelerated
soil erosion—coincide with pollen evidence of extensive forest clearing
and cereal cultivation around 4300 bc, when postglacial temperatures
in Europe were at a maximum.
Farmers had arrived, but Europe was still wild. Lions and hippopotamuses
lived along the Thames and Rhine rivers. While scattered bands of
people foraged around Europe’s lakes, rivers, and coast, a rich soil developed
beneath huge oak, elm, and beech trees that stabilized loess-mantled slopes.
Germany’s first farmers were drawn to the forest soil developed on silt
dropped by glacial winds between the Rhine and Danube rivers. Several
centuries later a second wave of related arrivals settled across northern
Europe in a band stretching from Russia to France. Soon farmers grew
wheat, barley, peas, and lentils on the region’s fertile loess. Hunting and
gathering thrived outside the loess belt.
Neolithic farmers kept livestock and lived in large longhouses near fields
along rivers and streams. Houses were occupied for the several decades that
the surrounding fields were kept under continuous cultivation. As isolated
longhouses began coalescing into small hamlets, farming spread beyond
the loess. More land was cleared and cultivated more continuously. By
about 3400 bc hunting for survival was history throughout central Europe.
German soils record periods of agriculturally induced soil erosion from
hillsides followed by periods of soil formation lasting roughly five hundred
let them eat colonies 85