306 ANNUAL KEPORT SMITHSONIAN INSTITUTION, 19 38 



wind erosion are repeated in Saskatchewan and Alberta (pi. 1). I 

 have myself seen the soil on the move on the great plains, drifts of 

 sand piled up against fences or any other obstruction, choking the 

 sunk roads, a most depressing phenomenon, especially when ac- 

 companied by swarms of grasshoppers, smaller but little less destruc- 

 tive than the locusts of the Old World. We have similar accounts 

 from Central Asia of the dust storms and encroachments of drifting 

 sand in the neighborhood of Bokhara. It has been stated that only 

 the Caspian Sea has prevented the march of the sand into the fertile 

 regions of the lower Volga. But of recent years the Soviet engineers 

 have discovered a means of getting a cover of vegetation again and 

 so stabilizing the soil. 



The causes of this terrible wind erosion are easy to discern. It 

 arises only in comparatively arid districts where the rainfall is below 

 the 20-inch level, and (in America, at any rate) where the fundamental 

 subsoil is of a rather sandy type — a recent glacial drift. Before white 

 settlement these regions were clothed with grass and were the natural 

 home of the buffalo. Some of the land was good grazing, with a fair 

 depth of black soil rich in humus, but in the drier parts the sod was 

 thin and there were only a few inches of soil. The black soil regions 

 were fertile and were the first to be broken up; the poorer land was 

 kept for ranching, healthy for either cattle or sheep if not too closely 

 stocked. The plow, however, began to encroach upon these thin 

 soils, with great rapidity when prices of cereals went soaring up from 

 1917 onward. At first all went well, for the cultivation began in a 

 cycle of good rainfall seasons, and there was some stock both of humus 

 in the soil and of accumulated rainfall below. The system of farming 

 that prevailed was of a wasteful type, a succession of cereals, or wheat 

 and maize with occasional timothy grass in the better lands of the 

 Middle West, but wheat and oats year after year in the Canadian 

 Northwest. The straw was burnt, no stock was kept; a few years of 

 such mining in the soil with no recuperative crop was enough to 

 exhaust the limited stock of humus. Then years of drought came 

 when the original subsoil reserve of water had been used up and the 

 light soil, no longer bound together either by vegetation or humus, 

 began to drift in the fierce winds that sweep over those great plains. 

 The plow had destroyed the binding power of the soil; the wind is 

 then able to remove the whole of the fertile top layer of soil and leave 

 nothing but the denser subsoil which is too infertile to carry a crop. 

 Nor has it been the case that the good soil is merely transferred from 

 one farm to the next; as a rule in Canada it has been swept right away 

 into the Great Lakes or the barren lands to their north, or even into 

 the Atlantic itself. 



It is sometimes represented that agriculture has been public enemy 

 No. 1, as destructive an exploitation as lumbering and more rapid in 



