This comes from an article by Wes Jackson in YES!
The article is mainly about how to restore the prairies, or rather how to re-invent perennial systems of farming. He concludes:
"As civilizations have flourished, many upland landscapes that supported them have died, and desert and mudflat wastelands have developed. But civilizations have passed on accumulated knowledge, and we can say without exaggeration that these wastelands are the price paid for the accumulated knowledge. In our century this knowledge has restorative potential. The goal to develop a truly sustainable food supply could start a trend exactly opposite to that which we have followed on the globe since we stepped onto the agricultural treadmill some ten millennia ago."
Clearly soil erosion has caused the collapse of many civilizations. As I write in Garden Earth:
Environmental degradation has followed man since his first attempts to farm, well even before farming. Also hunters caused substantial degradation e.g. by the extermination of large mammals in North Americas or many bird species in the Pacific. Soil erosion is one of the most prevalent and also one of the most harmful kinds of environmental degradation. It was an issue of concern for rulers of ancient Greece as early as the sixth century B.C. The lawmaker Solon proposed a ban on cultivating hillsides in order to prevent erosion. The ruler Peisistratos rewarded peasants for planting olive trees instead of cutting down forests and grazing livestock. Two-hundred years later, Plato wrote of land devastation taking place in Attica:
“...in the primitive state of the country, its mountains were high hills covered with soil, and the plains, as they are termed by us, of Phelleus were full of rich earth, and there was abundance of wood in the mountains. Of this last the traces still remain, for although some of the mountains now only afford sustenance to bees, not so very long ago there were still to be seen roofs of timber cut from trees growing there, which were of a size sufficient to cover the largest houses; and there were many other high trees, cultivated by man and bearing abundance of food for cattle. Moreover, the land reaped the benefit of the annual rainfall, not as now losing the water which flows off the bare earth into the sea, but, having an abundant supply in all places, and receiving it into herself and treasuring it up in the close clay soil.” (Plato Critias)
If not dramatic collapse, so at least the slow decay of most civilizations can be traced back to soil erosion and wasteful agricultural practices. It is a sobering insight that there are very few agriculture systems that actually have proven to be really sustainable, and for many of those it is thanks to external factors that they are sustainable, not thanks to the ingenuity of humans. The fertility of the Nile valley and other flood plains is mainly a result of erosion up stream bringing every year new soil and new nutrients downstream. David Montgomery states in Dirt, the Erosion of Civilizations, that most historic cultures lasted between five hundred and one thousand years. They start off with fertile soils created by natural processes. Fertile soils in hills with good rainfall are brought into cultivation as population increases, but soil erosion makes fertility fall. Marginal lands are taken into cultivation where fertility plummets rapidly and finally the whole civilization collapse, the area is depopulated until nature replenishes the soils again. He shows that Schwarzwald (Black Forest, today dominated by forests as its name indicates) in Germany has gone through three such cycles (Montgomery 2007).
I have written several posts about soil and erosion. And even more about agriculture