The Dust Bowl of the 1930s was a vivid example of wind
erosionunprotected topsoil blackened the skies, and drifted into ditches and
along fence lines. The result was unproductive fields and ruined crops. Since
then, the agriculture industry has made great progress in controlling and
preventing wind erosion.
Nonetheless, agricultural land across Alberta is still
subject to periods of drought and strong winds, particularly on open prairies.
During the recent drought of the 1980s, wind erosion
damaged an estimated 900,000 hectares of agricultural soils in Alberta. Strong
and sustained winds along with dry, bare soils contributed to serious topsoil
loss. Valuable nutrients were also removed with the topsoil, reducing the soil's
ability to produce crops. Coarser materials left behind by the wind, a reduced
topsoil layer, a decrease in the root zone depth and in the soil's water holding
capacityall contributed to further reducing soil quality and productivity.
Factors that increase the risk of wind erosion include a
sparse or absent plant cover, large fields and strong winds, and a loose, dry,
smooth soil surface. Soil texture and structure also affect wind erosion risk.
Loams, clay loams and silt loams generally resist wind erosion better because
the soil clumps are harder to break down. Soils with more organic matter help
to hold clumps together.